AC30 cranked

therose789

I have had my ac30 for a long time now and never really get the chance to crank it,

Was playing it tonight at rehersal in stereo with a Jackson Britain amp cranked in isolation rooms and my goodness it sounded soooooooo gooooood!

I always knew amps need to be cranked to sound good and it really is true with ac30s! Sounds like a totally differnt amp when you get it working.

Lovely stuff!

lustycourtier

Yup, but at that volume totally unusable live! Cant beat a good Vox.

impmann

/\ WHS... but I like AC30s just before they start overdriving properly. That harmonically rich sound that growls if you hit strings hard (a la Peter Buck)... but even that can be a little loud for a pub!

skay

Put a Rangemaster in front of a cranked AC30 and run!! Man, what a sound, but how loud!

Yeah Voxes do change considerably when you open them up, it's just that the opportunities to do that anywhere seems to becoming less and less 

maw4neu

A good Vox AC30 wound up to the max is an absolute joy to behold :-) The sheer volume is astonishing from such a relatively small amp . . . and, coupled with that amazing smooth creamy soulful drive its enough to vibrate every single bone in your body . . .  I love it when you can actually feel the volume and sense the air moving . . . . Thats probably why Im going deaf :-)  Another favorite of mine is the Fender Bassman . . . Thats another cracking amplifier when its at full tilt . . . Just light the blue touch paper and stand well back . . . I remember that I could genuinely feel the volume with my Bassman . . . Happy days :-) 

vasselmeyer

A cranked AC30 is one of the best reasons to use an attenuator. I had a 1967 AC30 for a while and rarely got the chance to crank it. But when I did...

ICBM

The problem is that they don't like attenuators! The only one I've tried that seems to give even tolerable results is the Airbrake, and even that takes away some of the magic. I think the reasons are both the power stage design - no negative feedback, so it's more sensitive to the load characteristics than most amps - and that a big part of the sound is the speakers, which are obviously being thrashed seriously hard when the amp is cranked unattenuated. And I suspect then has the double effect of altering the response of the amp even more - more than any other amp I can think of, the AC30 and the Blue speakers are a 'system', and neither sounds quite as good without the other.

Some amps take attenuators well, some attenuators work better than others with different amps, but getting both at the same time with the AC30 seems very difficult.

siraxeman

What model of ac30 does the OP have?
.my ac30 hw2x sounds great with my attenuator. ....at keast at gigging volumes. But crap at home levels. ....no surprises there then!

xscaramanga

I've got an AC30 clone that I bought secondhand so I don't know much about it (don't even know who made it), and it has Power Scaling.

For obvious reasons, I've never had a chance to run it at full blast, so I can't compare the tones, but all I know is it sounds good with the power scaling even at low volumes. If you've got an AC30 that isn't worth a fortune it might be worth investigating having that retrofitted.

ICBM's comment about the Blue speakers reminds me that I've never even got a properly Voxy tone out of my amp. I've used it with a Vox Nightrain cab, a Cornford 2x12, and a Zilla V30 cab. I got good sounds out of all three, but never the classic AC30 tone. Wish I had space and money for a matching cab. 

thermionic

I've said this before, but I had a 1962-ish AC30 when I was a student that was as clean as a Fender Twin. I had opportunities to crank it but it never growled. Nice sound, but no real distortion.

 

There were numerous reasons that could have been contributing to this - it was a non-Top Boost model, so lacking an ECC83 gain stage, the Blues were long gone and replaced with G12-80s, and it had been neglected and sorely needed a good service (poor student etc).

impmann

Wow - there was something wrong with that one...! I had a 62/63 AC30 that I ran with Greenbacks and no top boost - that growled like a demon over 1 o'clock on the volume control. Glorious amplifier...

therose789

I have one of the new c2 models, it has a master volume which is ok but once you get it past 4 o clock it just opens it up!

ICBM

thermionic said:

I've said this before, but I had a 1962-ish AC30 when I was a student that was as clean as a Fender Twin. I had opportunities to crank it but it never growled. Nice sound, but no real distortion.

There were numerous reasons that could have been contributing to this - it was a non-Top Boost model, so lacking an ECC83 gain stage, the Blues were long gone and replaced with G12-80s, and it had been neglected and sorely needed a good service (poor student etc).

I like G12-80s, but I can't imagine they would sound great with an AC30.

A big problem with old AC30s is that many or even most of them have had a long history of repair work and sometimes modification, and if this hasn't been done well  - or well but by someone who doesn't  really understand what an AC30 is meant to sound like - then the results can leave a lot to be desired. Quite a few people get put off them entirely by that sort of experience.

Years ago a friend of mine had an AC30 which a well-meaning electronics engineer had "improved" by changing the biasing arrangement with individual resistors, caps and trimmers so that each valve could be biased separately and accurately - which might be a good thing if you're trying to make a hi-fi amp - instead of the original single shared resistor and cap.

It sounded lifeless and weak. I removed the chap's work - which was a shame in some ways since he'd made a very nice job of it - and put back the "crude" single resistor and cap, and got instant great AC30 tone.

And another one where someone had made a simple mistake when replacing the 100-ohm screen resistors, by using 100*K* ones. The amp sounded fine at low volume. But that's as loud as it went - about 2 or 3 watts. And yet whoever did this (again, very neatly so I suspect a professional) can't have realised that there was still something major wrong...

57Deluxe

...did it make your hair grow long and cork-screwy and your sleeves excessively voluminous??

Voxman

Generally speaking I go along with ICBM re AC30s not getting on with many attenuators. But one that works beautifully with it is (somewhat ironically!) the Marshall Powerbrake.

ICBM

Voxman said:

Generally speaking I go along with ICBM re AC30s not getting on with many attenuators. But one that works beautifully with it is (somewhat ironically!) the Marshall Powerbrake.

Not ironic if your AC30 was built by Marshall . (90s-early 2000s.)

I normally really like the Powerbrake with Marshall-type amps and some others, but I found the Airbrake much better with an AC30 - at least vintage ones.