Modding a V4B to have master gain control?

rnilson · #1 08-31-2010, 02:23 PM

Is modding a V4B to have a master gain control a bad idea?
I can get one for a really good price, but the lack of master gain is really an issue for me. I want ampeg grind, but I don't want to go deaf. I know a good tech who said he could do the mod under $100 buck, but will that ruin the value of this vintage amp?

beebassdude · #2 08-31-2010, 02:30 PM

honestly V4's and V4B's arent that valuable, so i wouldnt worry about ruining the value. these amps in great condition go for around 800 bucks, so a mod like this might make it less appealing to a collector but if you plan on using this a lot then go ahead and do the mod.

i have a V4 that i had the 6550 mod done to and it was definitely a good idea for what im doing. and any mods you do, you can usually undo them if you really need/want to.

eyeballkid · #3 08-31-2010, 02:34 PM

why would you do this?.. the V4B gets ampeg grind starting at about 11 oclock.. that is at a TOTAL usable volume... in fact most complaints ive heard about the V4B is that the overdrive starts too soon and folks want more clean headroom...

pick up the amp and try it out.. i bet you find you dont need the mod.

johnk_10 · #4 08-31-2010, 02:34 PM

i definitely woudn't recommend it. IME, they get plenty dirty quick enough on their own without one. i'd use a VT pedal if you want it dirtier at low volumes.

IMO, now that people are realizing just how well they're built and good they sound, they are becoming collectible and a vintage amp is only original once.

eyeballkid · #5 08-31-2010, 02:36 PM

+100 on that

ps john.. Dont be tellin everyone how awesome they are...

BassmanPaul · #6 08-31-2010, 02:40 PM

Quote:

Originally Posted by beebassdude

and any mods you do, you can usually undo them if you really need/want to.

Not if you've drilled a 3/8" hole trough the front panel. The modification is indeed easy to do BUT this is a classic amp. The "grind" that I think you are looking foe comes from the output tubes and their interaction with the output transformer. A hundred watt amp is not that loud by todays standards and I feel that you'll cut the value of a nice amp for no real reason.

Paul

derridiandrift · #7 08-31-2010, 02:47 PM

I vote for not doing the mod. I owned one and agree that they don't have tons of headroom. A cheaper solution is to put a VT pedal in front of the amp. They sell for around $100 used. You might be hard pressed to find a tech to do that mod for less than that.

beebassdude · #8 08-31-2010, 03:01 PM

Quote:

Originally Posted by BassmanPaul

Not if you've drilled a 3/8" hole trough the front panel. The modification is indeed easy to do BUT this is a classic amp. The "grind" that I think you are looking foe comes from the output tubes and their interaction with the output transformer. A hundred watt amp is not that loud by todays standards and I feel that you'll cut the value of a nice amp for no real reason.

Paul

thats true, if hes adding another knob that becomes a problem. but the mods ive had done on mine (tube swap, added bias control) are all changeable.

JimmyM · #9 08-31-2010, 03:03 PM

if you want master/gain, get a v4bh or a magnavox v4 from the mid 70's.

BassmanPaul · #10 08-31-2010, 03:12 PM

Quote:

Originally Posted by beebassdude

thats true, if hes adding another knob that becomes a problem. but the mods ive had done on mine (tube swap, added bias control) are all changeable.

Certainly, all you've done is inside the amp and won't detract that much. To a collector it would be a world of difference.

Paul

rnilson · #11 08-31-2010, 03:36 PM

Well the guy said the tubes have been modded so I don't think it matters anyway...still for $350 bucks it might be fun to have around.

billfitzmaurice · #12 08-31-2010, 08:14 PM

Quote:

Originally Posted by rnilson

Is modding a V4B to have a master gain control a bad idea?
I can get one for a really good price, but the lack of master gain is really an issue for me. I want ampeg grind, but I don't want to go deaf. I know a good tech who said he could do the mod under $100 buck, but will that ruin the value of this vintage amp?

You can put the volume pot into an existing unused hole in the chassis, such as a second input jack, so it can be undone if desired. With todays PC board amps you can't do so, but with old point to point wired tube jobs it's a snap. I did so on dozens of Fenders back in the 70s.

Alex1984 · #13 09-01-2010, 01:43 AM

Don't do it! I thought the non-master volume may be a big deal breaker on my SVT-II before I pulled the trigger, but Jimmy convinced me otherwise.

After playing the SVT-II, I'd say the V4B volume should be more than manageable.

coreyfyfe · #14 09-01-2010, 06:08 AM

Quote:

Originally Posted by johnk_10

i definitely woudn't recommend it. IME, they get plenty dirty quick enough on their own without one. i'd use a VT pedal if you want it dirtier at low volumes.

IMO, now that people are realizing just how well they're built and good they sound, they are becoming collectible and a vintage amp is only original once.

+1 to all of this. Or you could get one of later 70s models which had master volume.