Favorite AC30 tone ?

[Chuck H]

Well dog my cats... but dam' if that isn't some identifiable VOX tone anyway.

I thought the same thing. There's a little dynamic response missing (I think) but compared to other recording of the era it's no great shakes. Just another example of how good musicians can "find" the music with whatever they happen to be using at the time. I (apparently) think that Mike Campbell playing his Broadcaster through a 5E3 sounds like an AC30!?! Who knows WHAT they did in the studio in either case.

[soundmasterg]

Well dog my cats... but dam' if that isn't some identifiable VOX tone anyway.

As far as other amps, studio photos do reveal a cream Bassman piggyback rig, and later on a variety of Fenders as you mention.

Also, as an owner of two fine Vox amps, both 60's AC50 and AC100, lots of terrific tone to be had there as well.

Does "Recording The Beatles" show Geoff Emerick's revolutionary method of using a bass speaker as a microphone? Adds some lowdown lows to bass and maybe kick drum tracks too. That guy was full of kool tricks.

Yes that whole UL period (Revolver, Pepper, MMT) has a very identifiable sound, and it is mostly Vox for guitars and bass.

I absolutely love vintage JMI AC50's and AC100's! Count me as officially jealous . I built myself an AC100 clone but haven't duplicated the AC50 yet. I have a Korg AC30 with Celestion Blues and owned it since new (1993). Its currently out of order but it works well and sounds good, though not on the same level as a vintage one.

I did mention there was a piggyback Bassman in use pretty early on, and yes you will see it in many photos. George Harrison apparently loved the amp and inherited it after the breakup.

"Recording The Beatles" doesn't show pictures of the bass speaker as microphone technique, but they do mention it in there. It is one of the best books I've ever gotten with so much interesting info in it about the equipment used, microphones, sessions, gear, personnel, etc. Definitely worth the price, as is the book on Vox amps.

Vox Amplifiers: The JMI Years

That one is probably the most complete book ever written on any amp manufacturer.

Greg

[soundmasterg]

I thought the same thing. There's a little dynamic response missing (I think) but compared to other recording of the era it's no great shakes. Just another example of how good musicians can "find" the music with whatever they happen to be using at the time. I (apparently) think that Mike Campbell playing his Broadcaster through a 5E3 sounds like an AC30!?! Who knows WHAT they did in the studio in either case.

Yeah I've heard Mike Campbell used his Broadcaster and a vintage 5E3 on a lot of their stuff. I can hear that in those tones you mentioned. I have a real 1956 5E3, and a Jap reissue Tele with a Stephens Design broadcaster set....and I think it is probably a similar sound to that one you describe. Mike Campbell is such a tasty player too...very much in the same house as George Harrison as far as fitting into the song, having good tone and chops, etc.

Who knows what anyone uses in the studio or what effects are added from the studio gear, but the ones I mentioned about the Beatles are pretty well known and documented in many places. I had heard that Tom Petty and the Heartbreakers used Vox Super Beatles on some of those early recordings too....they did use them on tours, but I can't imagine using them in the studio....they are f***ing loud and pretty sterile.

Greg

[Leo_Gnardo]

Yes that whole UL period (Revolver, Pepper, MMT) has a very identifiable sound, and it is mostly Vox for guitars and bass.

I absolutely love vintage JMI AC50's and AC100's! Count me as officially jealous .

I was officially lucky.

I built myself an AC100 clone but haven't duplicated the AC50 yet.

Hope you allowed plenty of extra breathing space for the output tubes. On the original item - AC100 - what were they thinkin'? Way small box to stuff 4 output tubes into. I run mine typically 1/2 to one hour at a time. Long enough for a Beatles concert back in the day. No way either amp can out shout a stadium full of screaming girls.

[Chuck H]

I absolutely love vintage JMI AC50's... but haven't duplicated the AC50 yet.

Yeah, you might want to get on that I built a customer order that switches between a BF preamp and an AC50 bright channel preamp into a pair of el34's in a 2x12 combo (using a pair of G12H Anni's). Add a reverb and bias wiggle trem. I tease this guy that he owns nicer amps than I do and I'm building them! The "Vox" channel is truly great to play through. It's not even "my" sound and I could just noodle with it all day. Totally worth building one if you want one.

[tedmich]

The AC30 is a versatile amp, always dug this sound, teamed with a 69 Les Paul Custom

Always loved how the solo just drops in and out

[Helmholtz]

My first amp was a second hand AC50 + original cab, bought around '68. I thoroughly compared it to the 1970 AC30 before I traded it. Never looked back.
I mean the AC50 was loud and powerful, but my strat leads just wouldn't sing no matter what I tried (Fuzz Face clone, treble booster). Might have been partly due to the speakers (Fane?).

[pdf64]

...I built myself an AC100 clone but haven't duplicated the AC50 yet...

When you do, make sure to get the OT spec right, not just a regular EL34 50 watter. They're massive, the stack is 50% thicker than that of a Marshall.
I've got the dimensions somewhere but can't put my hand on it at the mo
I guess that they may be full power rated down to 40Hz, with a G12H loaded 4x12 they certainly sound excellent for bass.

Re the AC30, I'm now pretty sure that the JMI schematics have an error, as the actual JMI's have C41 as 47nF rather than 0.005uF (V8 vib/trem mixer circuit) https://el34world.com/charts/Schemat...x_ac301960.pdf
The Marshall design/built 90s Korg RI even copies the schematic error into the actual circuit! https://el34world.com/charts/Schemat...x_ac3093pr.pdf
I guess that most every 'clone' does so too.

Ironically, although it was something of a low point for the brand, the schematics from the Dallas-Arbiter and Rose-Morris era at least got that cap value right https://el34world.com/charts/Schemat...x_ac30dals.pdf
https://el34world.com/charts/Schemat...x_ac301989.pdf

[Chuck H]

When you do, make sure to get the OT spec right, not just a regular EL34 50 watter. They're massive, the stack is 50% thicker than that of a Marshall.
I've got the dimensions somewhere but can't put my hand on it at the mo
I guess that they may be full power rated down to 40Hz, with a G12H loaded 4x12 they certainly sound excellent for bass.

I used a 30W rated OT from a Fisher stereo amp. The amp puts out all of 50W but it's a guitar amp after all and the bandwidth is much more limited. Seems to be working great so far. Certainly not as burly as you describe. Not even as burly as a 50W Dagnall either. But sounds just fine. Then again, I don't have an actual AC50 on hand to compare it to. I don't know the Primary Z for the AC50 but the OT I used is the ubiquitous 6.6k.

[Helmholtz]

I don't know the Primary Z for the AC50 but the OT I used is the ubiquitous 6.6k.

Watch out for the screens with 6.6k. 2xEL34s are fine with a Zaa between 3.2k and 4k. Real pentode screens are more at risk than beam tetrode screens at high load impedance.

[Chuck H]

Watch out for the screens with 6.6k. 2xEL34s are fine with a Zaa between 3.2k and 4k. Real pentode screens are more at risk than beam tetrode screens at high load impedance.

Indeed and thank you! A phenomenon I became familiar with some time after that build. I can't remember now, but it's possible I moved up one on the OT secondary taps and have it wired for 3.3k. I can't say when I may get that amp back on the bench, but I will be checking for that when I do.

[pdf64]

My notes are that this MkII dual channel AC50 (GZ34 rectified) OT had 175 (!) laminations in a 2.5" thick stack, 3.75x3". The ratio was 1:21 from the 8ohm tap, 1:15.2 across the full 15ohms, so a ~3k4 primary.
By comparison, a Dagnall 784-139 used in 50 watt Marshalls has 72 laminations in a 1.44" thick stack, 3.75x3.14".

[soundmasterg]

Hope you allowed plenty of extra breathing space for the output tubes. On the original item - AC100 - what were they thinkin'? Way small box to stuff 4 output tubes into. I run mine typically 1/2 to one hour at a time. Long enough for a Beatles concert back in the day. No way either amp can out shout a stadium full of screaming girls.

Yes I built it into a Sovtek MIG 100U chassis and head box. I kept the Sovtek PT but used Heyboer OT and choke...and they are very nicely made and much like the originals. I made it have a 2nd channel with much higher gain, and the first channel is stock with 12AU7's etc. I put the preamp voltages in between the AC100 MK2 and the 80100, and made it switchable cathode boas and fixed bias. I had to change to larger wattage cathode bias resistors twice as I underestimated, and I had to change the values twice to get the bias current low enough that it wouldn't kill the power tubes over time. They ran those things hot! I had to redesign a couple things I did, and got distracted by car repairs and some other things, so it is still sitting on the bench waiting for me to finish it. It sounds just like an AC100 in the cleaner channel though!

Yeah, you might want to get on that I built a customer order that switches between a BF preamp and an AC50 bright channel preamp into a pair of el34's in a 2x12 combo (using a pair of G12H Anni's). Add a reverb and bias wiggle trem. I tease this guy that he owns nicer amps than I do and I'm building them! The "Vox" channel is truly great to play through. It's not even "my" sound and I could just noodle with it all day. Totally worth building one if you want one.

That sounds like a cool amp! Is it a BF PI and power amp also? When I do an AC50 I'll keep their complete design...preamp, PI, and power amp. Or maybe I'll take a trip to England and see if I can find a used one...haha.

When you do, make sure to get the OT spec right, not just a regular EL34 50 watter. They're massive, the stack is 50% thicker than that of a Marshall.
I've got the dimensions somewhere but can't put my hand on it at the mo
I guess that they may be full power rated down to 40Hz, with a G12H loaded 4x12 they certainly sound excellent for bass.

I am pretty sure Heyboer makes a great clone. Their AC100 clone OT was fantastic, and much better and bigger than a similar Marshall or the Sovtek that was on the chassis prior.

Greg

[tubeswell]

https://youtu.be/g9SSw6o3sOY

[Leo_Gnardo]

https://youtu.be/g9SSw6o3sOY

Oh yeah! Hank Marvin: the reason so many up & coming UK guitarists just had to get a strat. A bright red one, preferably. Great pick! Don't know if that's what he's using on this track, but he sure caught everyone's notice with that outlandish streamlined modern looking guitar in the very late 50's and early 60's.

I was lucky to get to meet the man, twice.