Tell me about the Ampeg VT 40

althekiller

Supporting Member
Messages
1,120
Thanks for all the great info everyone. I order a tube replacement set to have on hand from fliptops and a new reverb tank.

The amp sounds great but it has been picking of radio stations (very loudly) in my house like an old fuzz pedal. Especially on the 0db input settings. I have a lot of pedals that do this but only in my house. I’ve tried to cut off all the power and usual suspects for that kind of noise but nothing helps. The mountain behind my house has a bunch of cellular or radio towers on them and I’m wondering if that is the cause...super annoying for when I want to jam on it at home.

Anyone else experience this with these amps? None of my other amps do this, only certain pedals.
 

Richard Guy

Member
Messages
1,182
It's a V4 squeezed into a 2x12 combo. Get hearing protection. Regarding the Stones, they used SVTs', not V4 stacks. Ampeg; Linden NJ were first, then Magnavox sold them under the Ampeg name in mid '70s'.
 

althekiller

Supporting Member
Messages
1,120
https://www.aikenamps.com/index.php/technical-q-a
Scroll down the page. There is a section on picking up radio signals.

Make sure you pick up some spare 6k11 tubes. They're not too difficult to find but they aren't made any more and that's your midrange circuit - which is where the magic is in these amps IMO.
Thanks I’ll check it out when I get home tonight and troubleshoot. Lots of good info on that link!
 

zombiwoof

Supporting Member
Messages
5,761
Yeah that's definitely true about many tubes. I think what happened in my case is that the amp was biased under the assumption that they were the same as the old 7027A tubes, which are 35 watt - but the new Sovtek ones I had in there were 30 watt. Somewhat misleading to call it a 7027A if it's essentially a 6L6GC.

As for other tubes, what are you using in the first two preamp slots? As in the two 12AX7s that are next to each other. I've had noise issues with those at times. The ones that seemed best were the JJ ECC83S, but those were my least favorite for sound. Eventually settled on some Sylvania short plate 12AX7s.

Unrelated, but who in NYC are you using for your amps? I generally send mine to someone a bit further away, but ones like the VT40 are a bit of a hassle.

Also, regarding fliptops, they're definitely worth checking out. I actually needed a new cabinet for mine as the original got damaged - they didn't even offer it as a standard option at the time, but they set me up with a really nice (and accurate) replacement. Last time I checked they also had the oddball tubes, but the only one that's not currently made is the 6K11 really.



Nice one - that's definitely a good price, especially if it's been serviced.

As far as tubes go, if you don't plan to use the reverb, I probably wouldn't worry about spare tubes for that part of the amp. I recall it uses one of the three 12AX7s and the 6CG7 tube. But as far as the others go, they don't really burn through them quickly - I've had 12AX7s become a bit noisy (popping/crackling) or microphonic but no problems with the others as far as I remember.

Here's the full list of preamp tubes anyway

12AX7/ECC83 (x3)
12DW7/ECC832
12AU7/ECC82
6K11
6CG7/6FQ7

I'd suggest getting all of those as JJs (with Electro Harmonix for the last one) if you go for new production tubes. The 6K11 isn't made anymore, so check fliptops for NOS options or substitutes
If you read the article from Triode Electronics I posted above, the 7027A in reality has the same wattage specs as the STR 6L6GC tubes from the same manufacturer. Specs on spec sheets were basically exaggerated to sell the tubes.
Al
 

TinFingers

Member
Messages
38
The amp sounds great but it has been picking of radio stations (very loudly) in my house like an old fuzz pedal. Especially on the 0db input settings. I have a lot of pedals that do this but only in my house. I’ve tried to cut off all the power and usual suspects for that kind of noise but nothing helps. ...

Anyone else experience this with these amps? None of my other amps do this, only certain pedals.
This happens to me. I routinely pick up bizarre voice broadcasts. Like Caribbean pirate radio preachers. No pattern to when it happens.

This happens with both the VT40 and my DRRI, though, so I don't think it's endemic to the Ampeg's design. Brooklyn is just a weird place.
 

harvey j

Member
Messages
1,274
Ampeg reverb is different from Fender Reverb you might really like it. Sometimes techs don't change the little electrolytics used for cathode bypass caps, sometimes they should. If a different tank doesn't get it working check that, I'm assuming the tube is good.
Also i think Ampeg uses a large capacitor to drive the tank instead of a transformer, it could be bad.
 

TinFingers

Member
Messages
38
Regarding the Stones, they used SVTs', not V4 stacks.
My mistake. On their 1969 tour, they were using SVT prototypes. They used VT22's on some tracks on the "Exile" sessions and I jumped to the conclusion that they had fully embraced the SVT's smaller (only 100W!) siblings. But you're right. The onstage pics I can find from 1972 clearly show the SVT's 4-input faceplate behind Keith.
 

zombiwoof

Supporting Member
Messages
5,761
My mistake. On their 1969 tour, they were using SVT prototypes. They used VT22's on some tracks on the "Exile" sessions and I jumped to the conclusion that they had fully embraced the SVT's smaller (only 100W!) siblings. But you're right. The onstage pics I can find from 1972 clearly show the SVT's 4-input faceplate behind Keith.
They also used the rarer guitar version of the SVT, the SVT-9 (9-10" speakers for some reason). I know they had at least one of those. Has anyone ever seen one in the wild?.
Al
 

TinFingers

Member
Messages
38
They also used the rarer guitar version of the SVT, the SVT-9 (9-10" speakers for some reason). I know they had at least one of those. Has anyone ever seen one in the wild?.
Al
These come up on NYC Craigslist from time to time (https://newyork.craigslist.org/que/msg/d/maspeth-ampeg-v9-bass-guitar-tube/6990943782.html). I have never seen a V9 with either the early blueline or the 1971-74 blackline cosmetics of the amps the Stones used onstage in '72. It looks to me like there's a mid-'70s "V9/SVT" version with the standard SVT knobs and 4 inputs, and there's a late '70s V9 with 2 inputs, distortion and reverb.
 

StompBoxBlues

Member
Messages
19,936
Actually I think Ampeg claims 60/120. I had a V2 I should never have let out of my grasp. With modern attenuators it would have been a lot more practical.
Al
as I recall you are right.

I kept trying to figure out if mine was a VT 20, or 40, but am pretty sure now it was a 40 (though I have this nagging feeling I called it a 22 at the time!)

anyway it was my first amp, bought with money I earned working in a lumberyard. In the seventies, and I was around 17-18.

the amp was HEAVY, and LOUD, and fantastic, I played an ES 335, and at band practice it was no problem but at gigs where I cranked it up, it was like riding a tiger, because it would feed back so with the semi hollow body. But TONE, my god. I haven’t experienced the same since. It was a 4x10” combo. Had a locking mechanism for the reverb tank. Had a polarity switch that I learned very quickly I had to test touching guitar strings with one hand and back of my hand to the mic (back of the hand so I wouldn’t have the reflex to grab and be stuck to the mic) and when I got a shock, switch polarity.

I really miss that amp, but nowadays wouldn’t be able to crank it anyway so...
 

amphog

Member
Messages
4,091
They also used the rarer guitar version of the SVT, the SVT-9 (9-10" speakers for some reason). I know they had at least one of those. Has anyone ever seen one in the wild?.
Al
I have one, V-4 pre amp, SVT power section. There were Dumble Steel String Singers based on the SVT power section.
 

drewl

Member
Messages
8,562
Great amps, crank it and it just screams "Can't You Hear Me Knockin"

Got one for $50 a while ago.
Repaired and restored it and used it for some gigs.
Heavy, loud little beast!
 

derekeugene

Supporting Member
Messages
738
You may have already seen this but its a great video for QOTSA tones using a VT-40.

For some reason, he keeps calling the amp a B15, but you can see its a VT40.

I only have personal experience with the V-4 and VT-22, but they're super similar. Tailoring the EQ and sensitivity to your liking can be difficult, especially the midrange. Its difference for each guitar and volume level, but once you get your mind wrapped around it you'll love it. They're clean up until ear splitting levels and take pedals well. I use the SSBS Mini and it's great for drive. A PoT sounds great too. I've never loved TS-style pedals through the V4, but that could be personal preference. I've tried a lot of different power tubes and found the Tung-Sol 6L6GCs to be my favorite. I was using the JJ 7027 and 6L6 for a while, but the TSs sounds excellent.
 




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