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Ampeg V4-B: Any mods to make more output?
- Thread starter Groover
- Start date
I use just a regular V4 b/c I couldn't find a V4B, but anywho, it sounds amazing and I always have enough volume for my needs. I use it with an Ampeg SVT-410HLF or a V4 4x12 loaded with Basslite S2012's. It sounds great! I think it's louder with the 410HLF being that it's a more efficient cab being ported.
I had the stock Sovteks replaced out of my V4B-AV head, with JJ tubes. I am unsure what they put in, but it made a significant difference. I have the original tubes in the boxes the JJs came in.
I am unsure if this helps, but on the JJ Electronics box, the 5881 tubes were replaced with "6L6 GC" tubes (4 ea.), 12AU7 was replaced by a "ECC 82" (1 ea), the 12AX7's were replaced with "ECC 83 S" (3 ea.)
I am unsure if this helps, but on the JJ Electronics box, the 5881 tubes were replaced with "6L6 GC" tubes (4 ea.), 12AU7 was replaced by a "ECC 82" (1 ea), the 12AX7's were replaced with "ECC 83 S" (3 ea.)
The 70s V4-B is wider than an SVT. The SLM V4-B and later V4-BH were the same size as an SVT-CL. The old ones were wider because they were sold with a 2x15 cab. They hang over the edges of any 4x10 or 8x10 cabs I've used. The SLM version sounds completely different from the 70s version, but still a great amp. Different is not always a bad thing.
They're plenty loud. If not, there's something wrong with it. I used mine at outdoor shows all the time and had no problems keeping up with two gtr players using a Hiwatt and a JCM-800 half stack. The V4B sounds FANTASTIC when you push it into power tube distortion, which happens at a lower volume (obviously) than an SVT.
I'd agree with the previous posts... don't mod the amp, buy a cab with really efficient drivers. If you still think it's not loud enough, get an SVT. If that's not loud enough, get two.
They're plenty loud. If not, there's something wrong with it. I used mine at outdoor shows all the time and had no problems keeping up with two gtr players using a Hiwatt and a JCM-800 half stack. The V4B sounds FANTASTIC when you push it into power tube distortion, which happens at a lower volume (obviously) than an SVT.
I'd agree with the previous posts... don't mod the amp, buy a cab with really efficient drivers. If you still think it's not loud enough, get an SVT. If that's not loud enough, get two.
I played a show tonight with a loaner 70's V4B as my Classic 400 **** the bed again. I also had problems w the power strip I run my pedals off of ...just a tuner, an English Muff'n, a Tonefactor Envelope Filter, Maestro Phaser and Ibanez Delay Champ. I wound up plugging my 75 Rick strung w/Chromes straight into the V4B. There was a bit of an adjustment period but I wound up not missing the other stuff ie the Classic 400 or the pedals at all. It was an eye opening experience.
It is loud. This head felt so powerful. I actually had to turn down twice and the volume was only at about 10 or 11 oclock.
A Rick 4001 into V4-B running at 4 ohms connected to a SWR Big Ben and an Avatar NEO 212 felt very zen striking the perfect balance of mids heavy grind and power.
The band got all kinds of compliments afterward both for our songs and the sound ie how the bass blended with the drums and the guitarist's tone and volume spec. a Fender Jaguar played through a Hot Rod Deville 410 w a zvex fuzz factory w a hard hitting drummer playing a 70's Ludwig Ringo kit
The hunt for a V4B begins....I won't call it G.A.S....I am on a vision quest.
Edit: I posted to this thread because the V4B was so loud. It was stock too. I can't foresee too many circumstances where I would need any more volume/output than what it had on tap.
It is loud. This head felt so powerful. I actually had to turn down twice and the volume was only at about 10 or 11 oclock.
A Rick 4001 into V4-B running at 4 ohms connected to a SWR Big Ben and an Avatar NEO 212 felt very zen striking the perfect balance of mids heavy grind and power.
The band got all kinds of compliments afterward both for our songs and the sound ie how the bass blended with the drums and the guitarist's tone and volume spec. a Fender Jaguar played through a Hot Rod Deville 410 w a zvex fuzz factory w a hard hitting drummer playing a 70's Ludwig Ringo kit
The hunt for a V4B begins....I won't call it G.A.S....I am on a vision quest.
Edit: I posted to this thread because the V4B was so loud. It was stock too. I can't foresee too many circumstances where I would need any more volume/output than what it had on tap.
The V4 pulls and distributes so much current and is so tonefully loud when it's stock, that I think trying to juice some more loudness would be kinda redundant. I'd try some different cabs or go get one of those widow making, dragon slaying, fire breathing old SVT's.
6L6GC has a heater draw of 0.9A - x4 = 3.6A
6550 has a heater draw of 1.5 - 1.6A = 6 - 6.4A
That is one hell of an increase in draw for the power transformer to supply above what it was designed to provide. You could add a separate supply but you will be diminishing the value of your vintage amp. You will get almost no increase in power output.
Paul
Ive used V-4s for the past 25 years. The reason to switch to 6550 output tubes has more to do with tone than output. To my ears, the V4 with 6550s sounds more like an SVT than the V4 with 7027s. I have all three. The SVT really isn't much louder than the V4. Keep in mind that to get twice as loud requires 10 times the power. To get twice as loud as a V4 you would need a full 1000 watts! The 300 watts of the SVT is a far cry from that.
Its important to understand that there are at least 3 different circuits called V4 from the Linden NJ days. The major difference between the early versions with the 6k11 tube and the later without relates to the screen supply. The earliest versions used 470 at 2 watts ala fender. If you want to run 6550s you really should increase the screen resistors ( r41,r42,r47, and r48) to 1000 ohms at 5 watts. Its not a bad idea regardless of your tube choice. You may need to change the bias network resistors to reduce the idle current. Ampeg reduced the idle current from the earliest ones as well.
The later versions don't have the 6k11 tube and added a 6an8 tube that the earlier ones don't have. They also have a very different screen supply. Rather than using a current limiting resistor on the screen they have a separate winding for the screen on the power transformer which drops the voltage down to about 340 from 530. Reducing the voltage on the screens reduces the gain of the tube slightly but greatly increases reliability. For the later amps, Ampeg them selves listed the 6550 as a direct plug in alternative to the 7027. I've been told that some even shipped with 6550s when 7027s ran low. I repeat, IF THE AMP HAS A 6K11, TUBE YOU SHOULD NOT USE 6550 TUBES WITH OUT MODIFICATIONS.
As the the issue of the extra draw for the filaments, On the later amps, they were clearly designed to handle the extra draw of the 6550s filament. I own 3 V4s and they are all early versions with the 6K11 tube. One is totally stock with 7027s, one uses 7027s but has had the screen resistors upped to 1000 ohms at 5 watts, and one has the upgraded screen resistors and is setup to run 6550s. I bought the one with the 6550s about 10 years ago and its my favorite of the bunch. Its my main amp. It was modded before I got it. I can tell you from first hand experience that the power transformer doesn't run any warmer than the two with 7027s.
Ampeg in the seventies loved to overbuild everything. I have no doubt that the power transformer can handle the extra draw. I don't know of another guitar amplifier that has a big enough output transformer to be useful as a bass amp. As transformers saturate, they loose low end. History is full of "bass" amps that work better as guitar amps because they have smaller transformers. ( Fender Bassman comes to mind ) but, only one guitar amp uses the same output transformer as the bass version and thats the Ampeg V4. The V4 and the V4B use the same transformers. They have the biggest transformers on a 100 watt amp I've even seen. Over kill. Its part of why they are so dog gone heavy. If your worried about the extra draw. just add a small transformer to power the filaments. thats what I did on a conversion of a deluxe reverb from 6V6s to 6L6s.
Just my 2 cents
Archie
Its important to understand that there are at least 3 different circuits called V4 from the Linden NJ days. The major difference between the early versions with the 6k11 tube and the later without relates to the screen supply. The earliest versions used 470 at 2 watts ala fender. If you want to run 6550s you really should increase the screen resistors ( r41,r42,r47, and r48) to 1000 ohms at 5 watts. Its not a bad idea regardless of your tube choice. You may need to change the bias network resistors to reduce the idle current. Ampeg reduced the idle current from the earliest ones as well.
The later versions don't have the 6k11 tube and added a 6an8 tube that the earlier ones don't have. They also have a very different screen supply. Rather than using a current limiting resistor on the screen they have a separate winding for the screen on the power transformer which drops the voltage down to about 340 from 530. Reducing the voltage on the screens reduces the gain of the tube slightly but greatly increases reliability. For the later amps, Ampeg them selves listed the 6550 as a direct plug in alternative to the 7027. I've been told that some even shipped with 6550s when 7027s ran low. I repeat, IF THE AMP HAS A 6K11, TUBE YOU SHOULD NOT USE 6550 TUBES WITH OUT MODIFICATIONS.
As the the issue of the extra draw for the filaments, On the later amps, they were clearly designed to handle the extra draw of the 6550s filament. I own 3 V4s and they are all early versions with the 6K11 tube. One is totally stock with 7027s, one uses 7027s but has had the screen resistors upped to 1000 ohms at 5 watts, and one has the upgraded screen resistors and is setup to run 6550s. I bought the one with the 6550s about 10 years ago and its my favorite of the bunch. Its my main amp. It was modded before I got it. I can tell you from first hand experience that the power transformer doesn't run any warmer than the two with 7027s.
Ampeg in the seventies loved to overbuild everything. I have no doubt that the power transformer can handle the extra draw. I don't know of another guitar amplifier that has a big enough output transformer to be useful as a bass amp. As transformers saturate, they loose low end. History is full of "bass" amps that work better as guitar amps because they have smaller transformers. ( Fender Bassman comes to mind ) but, only one guitar amp uses the same output transformer as the bass version and thats the Ampeg V4. The V4 and the V4B use the same transformers. They have the biggest transformers on a 100 watt amp I've even seen. Over kill. Its part of why they are so dog gone heavy. If your worried about the extra draw. just add a small transformer to power the filaments. thats what I did on a conversion of a deluxe reverb from 6V6s to 6L6s.
Just my 2 cents
Archie
Agreed... the Transformer on my V4 is nearly twice as big as the transformer on the "130w MusicMan HD212" i'm repairing. The Ampeg is huge.
and i couldn't resist posting this pic again:
...[love noises]
modded my v4 for 6550's...a slight increase in output, but tonally it was very much worth it. with the 6550's its sounds much wider and more open, which happened to be the sound i was looking for. if you're into more volume, definitely get more cabs, it makes a HUGE difference.
but here's my completely blasphemous question to anyone who might know. i'll preface this by saying that i don't care about preserving the vintage integrity of my amp (seeing as i've already modded it extensively, stripped off all the tolex and writing, and painted it bright blue) and i wouldn't be able to sell it even if (god forbid) i ever wanted to. here we go:
while doing a bit of researching, trying to decide if i wanted to go for the 6550's, i came across some forum for hi-fi systems where someone mentioned that 2 6550's could be wired/biased to run at 100 watts. so now i'm thinking...i've got 4 of em. is it at all possible to mod the power section of my v4 with 6550's to run at 200 watts? maybe even some sort of stereo set up, 100 per side? would i need new transformers to handle that? is this the worst idea you've ever heard, or could it hold water? would it even be worth it if is possible?
...just speculation at this point, but if anyone has an opinion on that i'd be happy to hear it.
billfitzmaurice
Commercial User
- Sep 15, 2004
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- Owner, Bill Fitzmaurice Loudspeaker Design
It's pretty much moot, as doubling power will only get you another 3dB of output, which is not worth the effort.
I have over 35 years experience in designing and building tube amps. I was trying to see if he was just being flip. Doing it right is a major undertaking especially if the original PT is not quite up to snuff.
