Rickresource Rickenbacker Forum

With so many companies(Fender,Epiphone,Crate,Peavey etc) competing in the small(5 watt) tube amp market it would be cool if Vox were to reissue the AC-4.Think it will ever happen?

Probably. Korg's done a really good job with the Vox reissues as well as some interesting new Vox amps since they've held the reins.

If you send them an email, they might reissue the amp even sooner than if left to think of it on their own.

Thanks,do you know their email address?

http://www.korg.com/service/contactus.asp

Korg USA, Inc.
316 South Service Road
Melville, NY 11747-3201

US Customer Service (631) 390-6500
US Product Support (631) 390-8737 or [email protected]


I would also love to see an AC-4 reissue. I still kick myself for selling the one I had about 8 years ago, it was a nice little amp!

doctorwho wrote:http://www.korg.com/service/contactus.asp

Korg USA, Inc.
316 South Service Road
Melville, NY 11747-3201

US Customer Service (631) 390-6500
US Product Support (631) 390-8737 or [email protected]


I would also love to see an AC-4 reissue. I still kick myself for selling the one I had about 8 years ago, it was a nice little amp!

Thanks Gary.I rarely see AC-4's on Ebay and when I do they go for alot more than I would want to pay.

Hey Guys,
I just had an amp made by Terry at D-Labs amps based on the AC-4 schematic (with a few changes), and I absolutely love it! He made me the chassis to spec to fit in an old 40's table radio cab that I loaded with a Weber alnico Blue Pup, and he only charged $275 shipped! It's all PTP wired with NOS USA transformers & Sprague caps. Stunning tone!!!!!

Just thought you might like to know.
Chris

Thanks for that info, Chris!

There's already a JMI version, I am sure it's not cheap though.

If Vox does make one, it would probably not have the same features (controls, tremolo, for example) though, same as their AC30s and AC15s, which don't seem to have the original Vox vibrato and the same control layout.

I always wanted Vox to make a reissue of this little amp. So at the end, I had an AC4 replica built from a small custom amp maker. It's based on the original AC4 circuit, we had a 60's Vox JMI AC4 example at hand when we started the project, but we made some changes (i.e. fitted a 10" silver alnico speaker, a ohm selector switch...). I absolutely love it, it's a perfect home playing amp. You can push it to the top to get its best, works really good with overdrive stompboxes.



Just a couple of months ago, I checked a JMI4, but it is a different creature, not exactly an AC4 replica...

Ahh, the AC4. I heart the AC4. Would love another one someday.

rickyvox wrote:I always wanted Vox to make a reissue of this little amp. So at the end, I had an AC4 replica built from a small custom amp maker. It's based on the original AC4 circuit, we had a 60's Vox JMI AC4 example at hand when we started the project, but we made some changes (i.e. fitted a 10" silver alnico speaker, a ohm selector switch...). I absolutely love it, it's a perfect home playing amp. You can push it to the top to get its best, works really good with overdrive stompboxes.



Just a couple of months ago, I checked a JMI4, but it is a different creature, not exactly an AC4 replica...

Great looking amp. Seems like it would be a really cool amp to have around!

Plus, there can be no argument that these VOXes aren't Class A!

- Scott

Plus, there can be no argument that these VOXes aren't Class A!

- Scott

Yah the AC4, being single-ended will be Class A, but the AC15 and AC30 are not.

Greg

Actually to be truly pedantic it's even debatable whether this (and most other single-ended guitar amps) are quite Class A. They are usually not biased correctly to center the operating point - in fact most are biased a bit too hot for it - and so they clip at the forward end of the waveform before they cut off. So really they're a sort of 'reverse quasi-Class AB single ended' . I really don't know why the Class A thing has become so entrenched anyway, since by definition it only applies to UNDISTORTED signals, which is pretty much missing the point as mostly these lower-powered amps are prefered exactly because they can be easily pushed into power stage distortion!

I've worked on a few original AC-4s and owned two, and all I can say is that I hope any reissues are not strictly historically accurate! I thought they were weak, ratty-sounding little amps that are nothing at all like their big brothers, even thought they look as cool as anything. I know a lot of the problem is the tiny ****** speaker. But there's also a design flaw in the original circuit - the feed to the OT is taken from the second node of the B+ chain, not the top one. For 'hi-fi' (where it was almost certainly borrowed from) circuits, this is normal and is considered a good thing because the second node is better filtered so hum is reduced, and these amps are never pushed hard enough for it to be a problem. But it also reduces the maximum power available, and in a guitar amp which will be pushed into distortion, it's a very bad thing because it then causes the plate voltage to fall below that of the screen when the power tube clips, which makes the screen act as a surrogate plate and draw much more current than it can handle safely, which shortens the tube life as well as not actually sounding very good (it produces a nasty, 'parpy' breakup). Luckily the fix is simple - move the OT feed to the top node, which means just changing one wiring connection on the cap can. I've done this to every AC-4 I've serviced after trying it on my first one, and it makes a big difference to the tone quality as well as making the amp noticeably louder.

Sort of good news/bad news ... Korg/Vox introduced the AC-4TV at the NAMM show last week, but it's not the same circuit as the original AC-4. I'll post a picture later tonight.