Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: neon333 on July 03, 2012, 01:05:42 pm
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Does anyone know of any mods for the newer ac15c1 (replaced the cc1). Not that the amp sounds bad, just looking for any tweaks to improve it. Not a lot of info on this amp on the web.
Thanks
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I don't know that amp or any mod for it, however
http://acapella.harmony-central.com/showthread.php?2649137-New-AC15C1-2010-Mods-Pictures-and-description-Clips (http://acapella.harmony-central.com/showthread.php?2649137-New-AC15C1-2010-Mods-Pictures-and-description-Clips)
K
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I find this other
http://www.diystompboxes.com/smfforum/index.php?topic=93904.0;prev_next=next (http://www.diystompboxes.com/smfforum/index.php?topic=93904.0;prev_next=next)
(http://i.imgur.com/4kRCt.jpg)
K
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Doug has schematics for a select number of the VOX AC15's. a few other 15s.
Do you happen to have a schematic of your amp, If so, please share.
No I don't. I was thinking about contacting vox for one.
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The AC15C1 is a true two channel amp. Each channel has one input. The first channel incorporates the preamp circuitry from the original AC-30 "Normal" amp while the second channel featured the Vox AC-30 "Top Boost" circuit. Three ECC83 tubes power the preamp.
The AC15C1 also has tremolo and a spring based reverb.
So the amp seems an old AC30 + reverb
This increases my interest to see a real AC15C1 schematic
Unfortunately my research on the net are negative
K
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I believe the best one can do is look at the pics on VOX's site, and look at the vintage schematics, then make guesses. (With the statement 50 years of experience I would look at the 1960 era schematics.)
The trem and reverb are IC-driven. It was also shown from the linked thread on mods for this amp that there are added bright- and dull-caps that were not present on any 50's-60's vacuum tube Vox.
If the originator of the mod thread is correct, there is at least one deviation in the Top Boost channel's tone circuit from the Vox original. Which is believable because the original was wired funky, but it also contributes to its unique functionality.
The modern AC15C1 has a bridge rectified B+, as shown in the mod-thread pictures. We can presume other power supply changes to support the sand devices.
It should be as simple as looking up the vintage schematic, but users have been griping about Vox amps bearing the AC30 and AC15 names since the 80's at least. Seems the AC15CC1 was particularly hated among folks who love vintage Vox amps, because the circuit bore no resemblance to its namesake. At least the prices were relatively low.
A real early-60's AC15 was very much like a 2-output tube AC30, especially if you look at the AC15 Twin (with 2x12 speakers).