5 Steps to Make Your Vox AC15C1 or AC15CC Sound Amazing

images The current production Vox AC15C1 by Korg is one of the most popular tube amplifiers being used among P&W guitarists today. At $599 USD for a new 1×12 combo it is undoubtedly one of the best bang-for-the-buck amplifiers readily available through major music retailers. Though these Chinese made PCB amplifiers have many strengths, they also have a few common weaknesses that are widely recognized among those who own them. Notably, poor bass response, grainy mids, and ice pick highs. In my experience working with AC15C1 and AC15CC owners to help them improve their tone I happened across a non-invasive formula that takes these little amps from good to great. Every one of these AC15 owners has thanked me for helping them bring out the mojo in their amp. I recommend trying these upgrades in the order listed. If you find a point where you are completely satisfied with the results, stop. Continue to the next step if you decide you want to take it to the next level. We usually don’t use our articles to sell product. However, a couple of the items recommended in the article are items we offer. We encourage you to purchase these products from whomever you please and support local businesses whenever possible.

1. Don’t clip the bright cap yet! ($0)

Most guys don’t realize that the Chinese Alnico Blue or Greenback is the reason for the shrill top end on these amplifiers. Clipping the bright cap removes the chime that made the original AC15 famous.

2. Install a Bad Cat Celestion Speaker ($189) *minus whatever you sell the original speaker for.

There are many speaker options that will yield a sonic improvement in these amps, and the Bad Cat Celestion is a proven example. So much so, my customers and friends have deemed it “The AC15 Saver”. This custom designed speaker is the secret weapon for balancing the tone on these amps. Developed for Bad Cat by Celestion to combine the percussive low end of a G12H30 with the creamy cone response of vintage Bulldog alnico, this 65w/ 100 db speaker gives the AC15C1 and CC solid bass, pulls the mids together, and puts a smooth layer of cream on the top end. Once this speaker is installed you may be glad you didn’t touch that bright cap. If it’s still too bright for your taste after this speaker upgrade, then you may want to give the bright cap mod a try. It’s an easily reversible mod if done correctly.  galery_image_126_724

$189.00 USD

Buy Now Button with Credit Cards

3. Replace the Speaker Cable & Plug ($15)

Believe it or not that short little cable can make a slight difference. If you decide to order your Bad Cat speaker from the “Buy Now” option above or our website http://tonesmiths.com/collections/amp-lounge/products/12-celestion-speaker  we will solder on a premium speaker cable with a heavy duty 1/4″ pancake plug or 1/4″ female jack  for absolutely free upon request.  This is the same cable, plug, and jack used by Bad Cat. This addition will ensure strong solder joints, proper phase connections, and save you time on the install too.

4. Install a New Set of Tubes ($60-$75)

There are many brands to choose from when your looking to retube your amp. JJ, Electro-Harmonix, and Groove Tubes are the most popular since they’re easily available at most music store chains. But there’s a  brand heralded by hi-fi enthusiasts that will absolutely change your life. These tubes are produced by legendary tube designer Peter M. Watson’s company PM Components. The crazy thing is they’re only a couple dollars more than JJ.  I recommend their 12AX7HG for the V1 position, 12AX7A for reverb (not needed for the CC), a 12AX7LM for the phase inverter, and a matched pair of their amazing EL84s. All I can say is prepare to be awed at the increase in output and fidelity these premium tubes provide. They’re so good I dedicated an entire Tonesmiths Report to them The Best 12AX7 on the Market. PM Tubes are only available through a couple US sources.  My friend Israel at http://www.tubeboutique.com is the fastest and most reasonable. He offers matched tube sets for every version of the AC15, has great prices, and ships fast.

Here’s a YouTube demo of an: AC15C1 with PM Tubes

5. Upgrade the Output Transformer and Choke ($260 parts/ $200 labor)

This is the most costly and labor intensive upgrade. At this point you will be into your amplifier a total of $850 if you purchased it new at $599. Upgrading the OT and choke to a Mercury Magnetics drop-in replacement will push your investment into the $1,300 range if you have to pay a professional to install them. You could buy a used boutique amp or an AC15HW for that! I would only recommend this upgrade if you are 100% convinced that you need more bass and touch sensitivity after the upgrades and you are planning to keep this amp for a very long time. *Note: With the exception of the transformer upgrade these mods have also been performed on the AC15HW with great results.


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137 Responses to 5 Steps to Make Your Vox AC15C1 or AC15CC Sound Amazing

  1. Matt says:

    Does it work with a Vox ac30 handwired ?

    • levil says:

      huh? you bought a AC30 handwired and want to mod it? what’s wrong with it?

      • tonesmiths says:

        The Bad Cat speaker improves the bottom end on these amps and PM tubes help considerably with headroom. These aren’t really modifications, just slight upgrades. Unfortunately Bad Cat only makes an 8 ohm version of their speaker, so it only works with 2x12s capable of running at 4 or 16 ohms.

  2. Alvin says:

    Could you put up a video of how one may sound totally upgraded?

  3. kevin says:

    yeah right, an AB test would be appreciated

    • tonesmiths says:

      I have countless testimonies and thank you emails from guys who have performed the speaker and tube upgrades with excellent results. They take these affordable AC15s into boutique territory with a minimal investment. Most amps require a retube as some point anyway, so you’re only out $159 if it doesn’t float your boat. I really discourage anyone from investing in a full transformer upgrade on a PCB amp as the benefits don’t justify the cost.

  4. Peter Busatto says:

    Hi there, I am new to tube sourcing and swapping and want to make my new AC15C1 more pedal friendly and replace the stock tubes. I have checked out the tube replacements you recommend above and they are affordable but I can’t afford to replace my greenback at this time. Do you think these tubes will make the stock amp more pedal friendly?

    • tonesmiths says:

      Simply upgrading to PM tubes will produce a more harmonically rich tone with increased headroom. Please be sure to put a 12AX7HG in the V1 position and a 12AX7LM in the phase inverter position. A used G12H30 will get you 90% of the way there until you can afford to upgrade to the Bad Cat Celestion.

    • tonesmiths says:

      The 12AX7HG in the V1 position will definitely increase headroom thereby making it more pedal friendly. The other PM tubes will also decrease the noise floor which tends to increase when coupled with overdrives.

  5. i really like this article.. some good information… im wanting to change my Chinese tubes.. I like the tones and crunch they deliver but i know i could have some better ones.. Are the PM’s you recommend gonna drastically change the overall vibe of the amp or is it still gonna be able to deliver that nice classic rock Crunch?

  6. Dean D. says:

    I performed steps 2 and 4 above. I did plan to do step 3 ( replace speaker cable) but the cable that came with the speaker was not long enough to reach out of the back of the AC15C1 and reach the extension speaker jack. So I had to reuse the stock wiring for the Bad Cat speaker. I haven’t had a chance to play in a real setting yet (will next week) but so far it sounds pretty good. I think the bass response is much improved.

    • Chris Wallop says:

      Re the frumpy bass, some of that will be the inherent personality of both the Vox AC and 15 watts in general. I have used the Greenback, a WGS Reaper and a Celestion Blue in the amp. All get a bit frumpy when driving the amp, esp on the Normal channel. My best solution has been an EQ, in my case the Earthquake Devices Tone Job. When i push the amp, I hit the EQ set for bass at 9-10 o’clock, the mid at 10 or 11 and drop the treble some too. This works. So my setup is to use the ABY switch, with the ToneJob in the Normal channel. When I either a.) drive the normal channel and/or b.) play both channels together, I use the EQ.

      • tonesmiths says:

        Unlike the V30, Greenback, and Alnico Blue, the Bad Cat Celestion completely cures the flabby bass. The 100db sensitivity maximizes the output of the AC15 and 65w rating keeps the low end clear and punchy.

  7. Chris Wallop says:

    Re the Bad Cat Celestion, it sounds like an excellent suggestion but I’m curious that it is only available in the 8 ohm version, when the AC151C has a 16 ohm out. Can you comment on how that mismatch might affect the tone and optimization of the 8 ohm speaker? Thanks a lot.

  8. Davide says:

    I can’t find badcat speakers in my country, only celestion and eminence speakers are easy to find. Wich speaker do you suggest as alternative choice with the same result? Thank you in advance.

  9. Brandon says:

    I’m debating between the Bacat speaker vs a Celestion Blue, which seems to be the more popular choice. What’s the difference in the two?

    • tonesmiths says:

      I’ll be the first to tell you that a vintage AC15 with an original Bulldog Alnico optimizes tonal perfection. However the Bad Cat Celestion pairs much better with the modern Vox AC15 much better than the modern production Alnico Blue. The Bad Cat speaker produces a percussive low end, tighter mids, and smooth top end that are the antithesis of the modern Alnico Blue’s saggy low end, grainy mids, and propensity for cone cry.

  10. Lukas says:

    i just received my PM tubes but im not really sure which one goes where i have a AC15CC. Anyone have the answer for me?

  11. Chris says:

    Are the PM tubes worth the extra money over Mullards?

  12. mrubin454 says:

    Reblogged this on Six Strings & Beyond and commented:
    This a great article for AC15 owners everywhere, that tube replacement might happen for my C1 Custom

  13. Rick says:

    I have an AC30-CC1 (yes, 1!) – do you think these same changes would benefit me like they do on the AC-15’s?

  14. Acres says:

    When you put in the matched PM EL84s did you have any new hum issues? I’ve read the AC15C1 is a self-biasing amp (even for the power tubes) but both matched pairs of PM EL84s I bought both develop an audible hum within 20 mins of being plugged in. What do you recommend I do? The stock tubes are completely silent.

    • tonesmiths says:

      After helping scores of AC15 owners retube their amps with PM tubes we’ve never had any produce those symptoms. A tube that isn’t making a proper connection either externally or internally will produce the mechanical him you’re describing. Please confirm that your new tubes are properly seated. If that isn’t the cause then confirm that all tubes are lighting up equally. It’s possible that a tube may have been damaged in shipping.

      • Acres says:

        Just letting you know my issue was that I left the back panel of the amp disconnected while I was testing out the new tubes. It turns out the back panel is lined with metallic material that makes contact with the rest of the amp circuitry when connected, “closing the loop” as it were. Similar to the layer of metallic tape on the back of a pickguard. Once I reconnected the back panel the hum went away. Thanks for your time!

  15. Diego says:

    Hello. Very interesting article. Here’s my dilemma. I have a regular ac15 c1. It takes pedals decently and eventually, i’ll try most of your mods. However, i own a roger linn adrenalinn3 which i mainly use for its modelling. Its manual says that it needs a full range flat response amp or at least an amp with an effects loop with line/instrument output selector or attenuator to bring out the best amp simulation. Is there a mod to put an effects loop in the ac15? Is it worth it? Is it a good idea? Which is your advice if i want to have faithful amp simulator and effects in the vox? (Of course, Apart from having the option of using the sound of the vox). Thank you very much for your time and blog. Cheers from Argentina.

    • tonesmiths says:

      I used an Adrenalinn III for quite awhile, so I’m very familiar with it’s features. The only way to effectively use the amp simulator without colorization is directly into a class D power amp. I wouldn’t recommend running it into your AC15 even if it did have an effects loop. A Blackface, JTM, or JCM amp sim would never sound right through a pair of EL84s. You would be better off running the AIII with the amp simulators turned off like I used to. If you like the AIII then I recommend giving the Strymon Mobius a look. They are higher quality and have a much lower noise floor.

  16. Nathan McGee says:

    Thank you so much for this helpful article. I am definitely looking into performing some of this mods. Real quick, I bought an AC15 LE with cream cab and Creamback speaker. I’m pretty pleased with the bass response of the speaker, but the highs can still have that ice pick quality to them. I want solid bass response, solid mid range, and chimey highs without the piercing ice pick. I too am debating between an Alnico Blue and the Bad Cat. The Alnico Blue is advertised as evening out the tone and bringing that bell-like chime to the top end without sounding piercing. I’m not sure what the bass is like however. And since the Bad Cat is advertised as having the bass of a vintage celestion, and the chime of the Alnico Blues, at half the price, I am wondering if that is the better option. When I read your comment about the Creamback being the closest to the Bad Cat though, that had me slightly worried. Essentially, I am looking for punchy, solid low end, pulling the mids together, and retaining the chimey bell like highs without piercing through Mt. Everest. I might have the opportunity to get a Blue pretty cheap, so I’m most worried about quality over cost. Although I would be very pleased to hear the cheaper Bad Cat is the way to go! I am only worried that the Bad Cat loses chime or does not break up at a good volume. What is your and your friends’ experience with this and what would you reccommend for me?

    Thank you!

  17. Pablo says:

    This has been a very helpful article! I have been wanting to upgrade the tone in my AC15-C1 for quite some time now. A few years ago, I purchased a retube kit from EuroTubes, and that improved the tone of the amp (especially the overdrive) considerably. One issue I’ve always had with the amp though is that the low end sounds very rumbly and muddy (especially when doing power chords with an extended 9th on the lower strings). I would prefer a much tighter lower end while still retaining that classic chime. That being said, it may be the case that the BadCat speaker is the way to go for my AC15-C1. How well does the BadCat speaker handle the AC15’s overdrive? How early does the speaker break up (do you have to crank the top boost channel)? Would you say this speaker favors clean tones, or dirtier ones? Does it handle both adequately? Generally, I always play with some crunch, but for Edge-like delay stuff I like a nice clean tone. In any case, I hope this speaker would be a solution to bringing together the muddy bottom end up the amp. Any feedback would be greatly appreciated!

    • tonesmiths says:

      The beauty of the Bad Cat Celestion is how it combines these three elements; 100 db sensitivity, 65 watt power handling, and a free moving cone design to deliver a smooth, yet touch sensitive, response at any volume.

  18. Drew says:

    I have a vox ac15c1 and it’s my first amp. I’m new to amps in general so forgive my lack of any solid knowledge on amps. I was looking into replacing the speaker because it seemed to have a sort of sagging bass (I don’t know how else to say it). I would like to get that bad cat speaker but what does that pancake plug or female jack do? Do I even need those?

  19. Pete says:

    I also have an AC15C1 which I would like to upgrade and would be interested in Tonesmith’s opinion when comparing the Bad Cat speaker and the Weber Blue Dog (which has been suggested to me by others).
    I am interested in which will get me closest to that early 60’s Vintage Vox sound (The Shadows) and I suspect that the speaker upgrade would be a good first step plus different valves down the track.
    Look forward to your comments

    • tonesmiths says:

      Both are great speakers. The Weber will get you the more traditional Vox sound with the grainier mids and softer bass response. The Bad Cat Celestion has more of a modern voice. The ceramic magnet has a percussive low end and super tight mids. The Blue Dog would be better for those clean surfy tones the Shadows were known for. If you’re really after the Hank Marvin sound you will need a top boost AC30 and plenty of spring reverb. After all Hank is the reason the AC30 came into existence!

      • Pete says:

        Thanks so much for your comments. As far as the AC30 goes, it was a consideration when I invested in the AC15 but just “too heavy” to cart around for me so hopefully following your suggestions will improve the sound. Would you still suggest upgrading the valves etc.
        Pete (from OZ)

  20. h0xl3y says:

    Do any of these upgrades work on the the Cambridge Reverb 30 Twin: V9320 that was released in 1999?

  21. Isaac says:

    would you suggest the speaker swap even to V112HTV with alnico blues in it?

    • tonesmiths says:

      IMHO modern Blues don’t truly capture the sweetness of the original Vox Bulldog speakers. The Weber Silver Bell is much closer. I recommend those if you’re set on alnico

  22. Pingback: Vox AC15 hand wired opinions? - MyLesPaul.com

  23. Brian says:

    What is the value of the choke used to replace the 1k resistor box ac15cc1

  24. Mike says:

    To anyone who comes across this article
    Just do it
    Did the tubes and the badcat speaker and wow. Complete new world.
    Dry, no pedals, high gain, low master volume, AND THERE IT WAS, that SOUND. BEautiful, creamy and fulfilling. Major full blown thank you to the folks at tone smith
    I am MORE than happy and giddy with my sound.
    If you have a ac15 just do the speaker and tube mode, you will find yourself in a new tonal world.
    Thanks again.

  25. Rick C. says:

    So why buy this amp if it needs so many changes?

    • tonesmiths says:

      That’s a good question! There are a lot of great boutique versions of the AC15. The Magic Amps Brit MKII, Gabriel Voxer, and Valvetech Hayseed 15 are three of my faves for unmodded vintage JMI tones. The downside is they are all close to $1k more in price than the Korg PCB offerings. The $159 Bad Cat Celestion and $100 PM Tube set does a great job of taking the $500 Korg/VOX AC15 into boutique territory for only a total investment of $760 for a 1×12 combo. I haven’t found anything else that comes close for that price.

    • jbo.z says:

      Exactly, I have a blue and it sounds amazing if you want big bass get a 4×12 cab and a head … Ac15 is a great bed room and recording amp… I cant find one comparison on a bad at speaker… And they are not on Celestions web site ?

  26. will says:

    I have an 8 ohm switch on my ac15 single 12. So the bad cat should work right? A little confused that your saying it will only work with 2 12’s

    • tonesmiths says:

      The Bad Cat Celestion will work with any 1×12 or 2×12 that has an 8 ohm tap. Though the 8 ohm setting on a modern AC15s is designed for running a 16 ohm speaker in an extension cab in parallel with the internal 16 ohm speaker at 8 ohms, it works fine with just an 8 ohm speaker. The wired speaker cable and outputs are wired together, so it doesn’t matter which one you use as long as the ohm switch is set correctly.

  27. Ivan K says:

    Hello Donny. I´ve just bought a new Bad Cat. Wondering if the correct way to install it is:
    1.Plug it through the internal cable
    2.Switch the impedance to 8ohm

    Is it that correct? thank you

  28. Music Mike says:

    Here is what I think after following steps one through four on a 15c1.

    First off, IMHO its totally worth it. Now, i will ramble for a bit…

    The sonic character of the amp is incredibly improved. The blog post is correct in saying that the bottom is tighter, mids are more focused and highs are less shrill. The sound is exponentially fuller, more focused and more powerful. My old settings are no longer relevant. It took me a day of shaking the house to realize that I needed to dial it back. I use the normal channel exclusively so i can’t comment on the top boost. In the basement I run it with the master up full and the channel gain at 9:00 with the master tone at like 4:00. I play a Nashville deluxe power Tele and the tone is incredibly smooth and rich in any position. This past weekend I played it for a couple hours at the club. The only change I made was to dial the channel gain up to just past 12:00. The amp had no problem hanging with a loud aggressive drummer and full band. At one point i asked the sound man how much of the amp he was putting through the mains. He was piping through a lot for two reasons: Although the amp was cranked on stage it wasn’t interfering with the FOH mix and secondly, the tone coming out of the amp was so sonicly rich that it was holding the rest of the band together. It was an open mic situation so i was not playing it all night. I got to listen to a great player with a vintage tele using it and it was awesome. Afterwards the guy pulled me aside to say that i really had the amp “dialed” and that he thought it paired perfectly with a tele.

    So before i did the upgrade i was frustrated that I could not get this amp to fit into the mix with my combo band, which does classic country. It was just too shrill, chimey, unfocused and everything you’ve experienced if you’re reading this. Although I have not taken it out with that particular band, its obvious to me that this amp can now hang and even conduct in any classic rock, rock, country type situation.

    Regarding the speaker: The speaker is obviously well made and it mounts perfectly. The improvement over the greenback can not be understated. If you’ve read the blog and posts you’ll see mention about the bad cat vs. a blue. I’ve never used a blue but the reasoning for going bad cat sounds well thought out and hearing this set up I can’t help but think i’d be disappointed with anything else. Shipping was instant and well packed. The Bad Cat is a little heavier. I believe the cabinet is now 50.6 pounds.

    Regarding the PM tubes: Get them. I will never use anything else. The tube compression is absolutely fantastic. The harmonics they put off are incredible. Words can’t express it. At one point I thought the tubes were going bad but it turns out it was just harmonics interacting with the stock reverb tank. They are so incredibly well done its ridiculous. I sent Israel an email. The tubes were tied up in customs for a few days. Once they got them, the shipped same day.

    Regarding the install: Once i got into the amp i was a little disappointed with the build quality. There is glue and crap all over the internal circuit board. Also, I was confused about how the speaker cable would come. I didn’t understand that the stock amp does not use a quarter inch plug for the speaker. Rather, the stock speaker is connected on both ends by simple slip on crimped wire clips. The Bad cat speaker showed up with a quarter inch switchcraft pancake connector on one end with the wires soldered cleanly and properly to the speaker. Once you install the speaker in the cabinet you plug it into the external speaker jack and switch the selector switch to 8ohm. When you re-install the back panel you will find that there are small notches cut into the panel to allow the speaker wire to run to the jack. Once you plug the new speaker in you will notice that the other output jack and the ohm selector switch are now covered. This tells me that vox expects buyers to put a different speaker in the amp. Its a very well thought out design. The bad cat speaker cable length was perfect.

    It still sounds like a Vox. In researching I read a board post that said if you don’t like the sound of the amp you shouldn’t sink money into it. I now completely disagree. The ice pick highs didn’t totally go away but you can command them better. The modified set up makes the amp so much more musical. Actually, it just plain makes it musical, as before it just sucked (which I didn’t know at the time-i liked it initially). It actually makes my tele a better instrument, it sings now.

    I posted some pics on my instagram @MusicMikeRocks. I hope to post some before and after recordings on my reverbnation page @ MusicMikeRocks – we’ll see.

    Thanks guys for the advice and the service. Top notch. Peace

  29. Stephen says:

    Do you guys recommend these mods for an AC15C2?

    • tonesmiths says:

      Yes, we’ve had a few C2 owners perform these mods with excellent results. The tube set is identical, but the 8 ohm Bad Cat speakers must be wired in series to match the 16 ohm output of your amp. They come stock with two 16 ohm speakers wired in parallel at 8 ohms.

  30. Chris says:

    How do I order the pm tube re-kit? The website says it’s sold out . Thanks

  31. Morgan O'Brien says:

    I am ready to start the mods. My guitar teacher, a life-long jazz guy, recommends Canabis Rex, which he just put in his Blues Junior. Have you tried this or compared to the Bad Cat? His BJ does sound great, but I know it is a completely different circuit. CR is half the price, though.

    • tonesmiths says:

      I like the C-Rex for mid-scooped American Blackface circuits with inherent flubby bass. It worked really well with my old Rivera Era Fender Blackface amp. The UK made Bad Cat Celestion pairs much better with British circuits since they tend to be more pushed in the mids. I also recommend moving away from Vox inspired amps if jazz is your primary genre. Blackface circuits work much better for jazz.

      • Morgan O'Brien says:

        Thank you for the quick reply. I’m learning a huge amount about techinique and voicings from this teacher, but I’m a lbues and folk rock guy at heart (and ability level). Sold my Fender Supersonic 60 to finance the AC15 and the mods recommended here. The C Rex suggestion was his, so I thought I’d ask. But I love the Vox in ways the SS60 just didn’t do for me. So, I’m on my way. Thanks again.

  32. Thomas says:

    I have the purple AC15 that I actually got new in a unopened box for $500. I am going to do the speaker upgrade but what really bugs me about this amp is the reverb. Its bad. Any suggestion? I have the AC15C1. Thanks.

  33. Thomas says:

    I wanted to ask one more thing. Do these mods sound good at bedroom volumes? Some people seem to think that these are great amps but not small room amps. Before I wanted to invest the money I wanted to get your opinion. Thanks.

  34. Stephen says:

    Do you recommend these upgrades for the VOX AC15C2?

  35. Chris says:

    OK, I did the speaker upgrade for my Vox AC15C1. The results were fantastic! Here is what I
    discovered. My original Vox came with the Chinese Alnico Blue which ramped up the price of the
    amp quite a bit. I was able to score an open box price though. In retrospect, I would have picked
    up a used Vox(which you can get for excellent prices) and done the full upgrade with tubes,speaker and reverb tank. You can save a ton of money buying a used vox then doing the upgrade. I appreciate anyone that reads my humble opinion, I am no expert on amps etc…but I am a tone freak. I play a limited edition American special strat with Texas specials.
    I put at least 100 hours of guitar time on the amp before the upgrade just to make sure I did or
    did not like the tone of the Chinese Blue.

    Here are the results from the original amp with the Chinese Blue Alnico:
    1. At bedroom levels: average tone,lows very muddy and the highs were not nice and chimey. I
    had to bring the volume way up to get the nice chimey tones. I had to tweak the pedals a lot
    more in order to compensate for the shortcomings of the amp.
    2. At higher volume levels,master and top boost at 12’o clock the amp was pretty darn loud.
    The lows were a little better but the highs were tinny and I found out what the “ice picky
    tone sounded like.
    3. Overall The blue wasn’t bad but the previous things that were said about them were true.

    Here is the results after the upgrade to the Badcat speaker only. I haven’t done the tube
    re-kit yet.
    1. At bedroom levels: Excellent tone, warm and creamy lows,the highs came through
    nice and smooth. The nice chimey tone was pretty darn good but at bedroom levels not optimal.
    the pedals sounded really good. I had to do a lot less tone tweaking to get nice tone with
    the pedals.
    2. At higher volume levels,master and top boost at 12’o clock:
    The closest thing to tonal heaven! The results were night and day. Like I said earlier
    I’m not an expert but my ears don’t lie! The tone was fantastic. How much closer to perfection
    can you get without spending $4000 for a super high end boutique amp. The tones were
    incredible. After putting hours on the Chinese Blue then upgrading to the Badcat, it was
    worth every penny. My wife who has to put up with me playing incessantly for hours noticed
    the difference. Super warm creamy tones perfect chimey highs and mids. Those subtle notes
    played on the guitar that are lost in the usual wall of sound were refreshing to the ears.
    I’m glad I did the upgrade. It pays to get quality gear. I’ve already ordered the PM tube re-kit
    and reverb tank and am looking forward to installing them.

    3. Regarding Donny and the Tonesmiths:
    Donny was excellent to work with, he walked a newcomer like me though the process of
    gathering information and purchasing. Donny answered every e-mail I sent and gave
    me excellent level headed advice. From questions about installing to general questions
    about the upgrade, Donny was a cool cat. I never felt he was trying to sell me a product.
    But Donny is a fellow tone freak is well informed! And above all he’s a nice dude!

    This my humble opinion and thanks for reading anyone. It is well worth upgrading your

  36. Chris says:

    Anytime Donny, I’m glad I did it. Now I can punish my wife with hours of great tone!

  37. Justin says:

    I recently replaced the greenback in my AC15 with the badcat. It is amazing, made everything i loved about the amp even better and fixed the few problems I did have with the tone. I plan on changing to the tubes that were suggested in the article as well when the time comes to replace them. Just wanted to say thank you.

  38. Mik777 says:

    Would the badcat speaker work for my Morgan Ac20? And would you recommend the PM tubes as well?

    • tonesmiths says:

      The Bad Cat Celestion is the perfect speaker for any AC15 inspired amp. I wish I would’ve made that discovery before I traded away my AC20 for a 65 Amps Soho. The ASW KTS70 was a little too strident with the AC20. After an extensive A/B session I swapped the G12H30 in my Soho for a Bad Cat Celestion. I love that speaker!

  39. Stephen says:

    I replaced my stock tubes with PMs as recommended. It sounded great! But the PM EL84’s started producing weird staticky, morse code-ish, crackling sounds after the first use. I ignored it for a couple weeks, but eventually swapped out the PM EL84s for the stock, which fixed the problem. Has anyone ever approached you with this issue before?

    • tonesmiths says:

      During the time I sold PM Tubes. I only had a handful of tubes that were bad out of hundreds shipped. Unfortunately even premium tubes like PM are subject to damage during shipping. I recommend contacting the dealer you purchased them from. You’re in luck if you purchased them from http://www.tubeboutique.com. They have excellent customer service and I’m sure Israel will replace them at no cost for you.

  40. Daniel says:

    What about upgrading the cabinet? I found out today that the cabs on the ac15c1 are mdf. Would a pine or voiceless birch ply cab make any notable improvements? Maybe slightly different dimensions or ports instead of open back to improve bass response?

  41. Trenton says:

    In your opinion is it best to do these upgrades or just invest into a better starting amp? What’s more worth the money? I love the Vox sound and would love for this to take my amp into pro/boutique sound quality, which it sounds like you believe it will, but would it be better to just invest in a Vox HW, or some sort of Fender? The new Bassbreakers look pretty great. I’m just looking to invest into pro gear finally.

    Also, what are your thoughts on Scumback speakers? How would the Scumnico’s compare to the Bad Cat?

    • tonesmiths says:

      I generally discourage guys from trying to “turn a VW bug into a Porsche”. Speakers and tubes are performance enhancing parts like tires that must be replaced in time anyway. These affordable upgrades definitely take the AC15 CC1 into boutique tone territory. However the Korg made Vox amps are nowhere close to the quality of a hand built amp. Even their “handwired” HW amps use the same cheap Chinese components as the cheaper versions. If you feel ready to step up to the next level, I recommend trying some amps in a local music store that carries boutique amps. If you find something you like then try to find one on the used market. That’s a good way to get your toes wet since most boutique amps depreciate 30-40% once you take them home. Please refer to my Tonesmiths Report entitled “10 Questions to Ask Yourself When Purchasing a Tube Amplifier” before you go shopping.

      • Trenton says:

        Got it! Thanks! If I decide this is the right way to go for me, what upgrade should I do first? Should I start with the tubes or the speaker? I already have installed a G12H30, but I think it can get better.

        And, by the end of upgrading the components would you say the amp gets boutique? Technically those upgrades still make the Vox amp cheaper than actual boutique amps.

      • Trenton says:

        And what would you recommend for getting really deep bass, but retaining the Voxy highs, mids, and saturation?

  42. tonesmiths says:

    This is exactly what I was searching for when I landed on the Bad Cat speaker. It was the only speaker that retained the chimey highs while thickening up the bass.

  43. Dave says:

    I just bought an AC15 on black friday for $400 and I am very interested in making some upgrades.

    Question 1: Are you planning on doing an A/B test video so people can hear the difference between a stock AC15 and your upgraded version?
    If the differences in the video are noticeably better than the stock AC15 (with a Greenback) I’d order the Bad Cat speaker and PM tubes in a heartbeat.

    Question 2: There’s a Bad Cat 4×12 cab at my local guitar store and AC15’s. If I were to run the Bad Cat cab via the AC’s external speaker output would that give a good idea of what upgrading to the Bad Cat speaker would sound like in my AC15? Of course the guitar store’s Vox would have the stock tubes though.


    • tonesmiths says:

      Although I have testimonials from quite a few excited customers that performed my suggested speaker/tube upgrade (some are in these comments), none who have promised to shoot an A/B video have delivered. Though the Bad Cat 4×12 may give you a basic idea of the frequency response of their speakers the closed back construction is going to add a lot more low end and provide a much tighter feel than your open back combo. But it’s worth a shot!

  44. It’s a honor to have the possibility to read your article about how to get the VC15 sound best .

    I have one of these new made in china, in particulary the limited red edition with the V-Type Speaker. And now that I played a couple of hours with te amp at my house I noticed what you mentioned: “poor bass response, grainy mids, and ice pick highs. I feel a little sad because of this, but it’s what it is.
    For now I’m trying to make the right decision. I sell it and buy maybe a fender blues deluxe ressue or buy a Bad Cat and put in the VC15. I definitily need more bass and some headroom.

    The problem for now is that I can’t find the Bad Cat here in my country (Portugal)

    My needs are a great clean and bass response at the same time.
    Unfortunaly I can’t get the twin reverb or a deluxe reverb, they are very expensive, but it’s my kind of spirit.

    Thanks for your attention and sorry because of my poor english.

    • tonesmiths says:

      Thanks for reading the Tonesmiths Report. It will cost you a little more and they don’t include the speaker cable with plug, but Bad Cat may be willing to ship one to you in Portugal. If they are willing to ship a speaker to you, you can sell your old speaker to help recover some shipping costs. Email brian@badcatamps.com and let him know that Donny from the Tonesmiths Report referred you. He might make an exception since they don’t have any dealers in your country.

  45. Tom says:

    I have done the tubes and they sound great, the speaker is next!

  46. Steve Goldstein says:

    Hi, great article!!! Big Edge fan from U2 here. If you have any specific suggestions other than what is in your article for getting his sound, please let me know. Replacing the tubes first. It’s all I can afford right now after purchasing a brand new AC15C1. Will JJ tubes work well for an upgrade to my Vox AC15C1? Everyone is telling me JJ tubes are the best. If so, do you happen to know which ones to get? Also, for home recording I purchased a load box. Do I need to remove all the screws on the back of the amp to access the speaker cable? Many thanks!!!

    • tonesmiths says:

      I’m a big fan of the Edge too. This Music Radar interview with Dallas Shue is the most definitive resource I’ve found about his gear:http://www.musicradar.com/news/guitars/u2-exclusive-the-edges-stage-setup-revealed-223342.

      Re: Tubes
      JJ tubes have a rigid sound that comes nowhere close to the harmonically rich and naturally compression sound produced by PM tubes. Unfortunately they are more known amongst hi-fi enthusiasts than guitarists. JJs also have a high failure rate.

      Re: Speaker Cable
      I recommend disconnecting the existing speaker cables at the back of the speaker, covering the tips with shrink wrap, and fabricating a new cable that will reach the jacks on the back of the amp. This will allow you to reroute through the load box. Just be sure to leave enough slack to reach the load box while it sitting atop the amp. Any of the speaker outputs will do as long as the ohm switch is set to the proper load.

  47. Steve Goldstein says:

    Many thanks! Will check out the PM tubes. Excellent article you referenced, too. It seems Shue emphasized the importance of breaking in a new speaker…putting mileage on it, in other words. Any tricks for breaking in a new speaker to speed up the process? Also, good news. According to the Vox website, the new AC15C1’s have an ‘EXTERNAL SP: This speaker jack will mute (disconnect) the internal speakers and you can hook up either a 16 Ohm or 8 Ohm cabinet.’ Which means I don’t have to remove the back of the amp, thankfully. A simple speaker cable from the load box into the External SP will do. Eventually, I’ll have to remove the back of the amp to replace the tubes…but not for now. Thanks again!

  48. Erik says:


    I’m thinking of getting a vox ac30 hardwired head and then purchasing a 2×12 unloaded cab from Janice. Would you still recommend the Bad Cats over the Alnico Blues for this set up?


    • tonesmiths says:

      In my humble opinion, modern Alnico Blues sound nothing like the original Vox Bulldog speakers from the 70s. But, then again, nor does the Vox HW series sound anything like the originals. This is likely due to Korg using the same low quality components they use for the Chinese version. That’s the reason the HW version only sounds about 10% better than the one costing half as much. Therefore I would recommend not only purchasing Bad Cat Speakers, but Bad Cat’s take in the original Vox top boost circuit, the Cub III 30. This amp offers footswithable 12AX7 and EF86 modes and lead boost, their patented K Master attenuator, and comes with a transferable lifetime warranty. Remarkably, they only cost a couple hundred dollars more than Korg’s AC30 HW.

  49. Xwpis ONOMA says:

    You are basically saying spend as much you paid for the amp (and maybe more) to make this better. No, I am not buying it. VOX could have made it a better amp, but they didn’t. Not worth it.

    • tonesmiths says:

      My article actually discourages the more costly transformer upgrades. The most dramatic improvements come from the recommended tube and speaker upgrades. Tubes need to eventually be replaced anyway and the Bad Cat speaker ($187 shipped) is less than a $100 investment after you sell your old speaker for $100. $87 is a very reasonable investment for the drastic improvements you’ll hear. It’s just a shame Korg doesn’t ship them this way.

  50. Steve Goldstein says:

    Unfortunately, the PM tubes you recommend are out of stock at the moment, so, I just replaced all the stock Chinese tubes in my AC15C1 with some brand new JJ’s. I did it more out of curiosity than anything else. I can’t hear any difference. I am baffled.

    Any thoughts???

    • tonesmiths says:

      JJ tubes aren’t what they used to be. Having worked with a major amp maker I got to witness how many JJs got removed and thrown away in the quality control process. PM tubes on the other hand have proven to be very reliable with less than a 1% failure rate. Their reproductions of NOS designs are also far more musical than the ones produced by JJ’s industrial approach. The PM 12AX7HG I recommend in my article is also a very critical component to increasing the headroom. It’s an original design that by definition contains too many internal elements to be a true 12AX7. However the added stabilizer elements are what allow for 20% more current without the risk of increased microphonics. I recommend at least upgrading the V1 to this tube once Tube Boutique has them available. The Bad Cat Celestion also makes a massive difference if you haven’t done that yet.

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