200 Watt SVT? How to do it?

fu22ba55 · #1 08-31-2010, 09:36 PM

I've heard horror stories about people yanking two of the power tubes out of their SVT (the leftmost, and the rightmost) in an effort to get a 200 Watt SVT... but this method is apparently bad for the output transformers.

Would it be possible to get a 70's SVT with a bad transformer, and source two NEW transformers to make a 200ish watt SVT?

How would you bonfide amp techs go about doing it?

Please don't point me to Traynor, or Reeves, or Orange or HiWatt or Boogie. I'm talking about a 70's SVT pre, with a 200 watt 70's Ampeg output stage. (or whatever you'd get with only 4 6550s in an SVT.)

(I know I could just get two V4B's, but humor me.)

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EDIT for future readers: Thanks for all the great suggestions on alternate 200W amps, fuzz pedals, and speaker attenuators, but that's not the question I'm asking. I'm curious if it's possible to MOD an existing 300W SVT down to 200 watts, or mod a 100W V4B up to 200W. Read on for the mod suggestions!

Ben Clarke · #2 08-31-2010, 09:41 PM

What's the point? The difference is 1.5 dB.

JimmyM · #3 08-31-2010, 09:48 PM

ya, if you want a 200w amp, just get a 200w amp. it could be done i spose, but i'd be too afraid it would futz with the character of the amp.

taurus1 · #4 08-31-2010, 09:49 PM

don't be a scaredy cat, just yard a couple of those 6550's out and go for it. SVT's are designed to keep running when tubes fail. an old traynor could handle it.

Ben Clarke · #5 08-31-2010, 09:55 PM

The only stress I can see (and I am not an expert) for the OPT if pulling output tubes is that the output impedance of the amp would go up (I think - Google around to check me), so you would need to be mindful of that.

fu22ba55 · #6 08-31-2010, 10:08 PM

Quote:

Originally Posted by Ben Clarke

What's the point? The difference is 1.5 dB.

I'm a power-tube distortion kind of guy.

Sound men hate me. I hate them back.

120 Watt amps (Sunn, Orange, etc...) aren't loud enough.

Even my Boogie D-180 doesn't seem loud enough at times.

The Reeves 225 is in the sweet spot if you want to dime the amp and not get hauled off by the decibel police...

But I love the dimed 'peg sound. How to get the dimed SVT sound at 2/3rds the volume?

(This is really just a thought experiment. I know fuzz pedals exist.)

Ben Clarke · #7 08-31-2010, 10:23 PM

Gotya. Just get power tubes that break up earlier. 1.5 dB is really barely noticeable. Another alternative would be to get slightly less sensitive speakers.

fu22ba55 · #8 08-31-2010, 10:33 PM

Quote:

Originally Posted by Ben Clarke

Gotya. Just get power tubes that break up earlier. 1.5 dB is really barely noticeable. Another alternative would be to get slightly less sensitive speakers.

This is intriguing. I've always been baffled when it comes to tubes. I've been putting St. Petersburg winged C's in there for a while now.

What power tubes (or preamp tubes) would you recommend for more breakup sooner?

And I have noticed a difference depending upon speaker cabs.

So this is a failed thought experiment? Changing out the output transformers would not work? Or be cost prohibitive? (Again, the idea is to find a roached-out SVT. I'd never cut up a good one.)

David1234 · #9 08-31-2010, 10:37 PM

Maybe just get some less efficient speakers?

fu22ba55 · #10 08-31-2010, 10:41 PM

Quote:

Originally Posted by JimmyM

ya, if you want a 200w amp, just get a 200w amp.

Boogie D-180/Buster: too Metal. Too L.A. My D-180 will soon be for sale.
Aguilar DB-359: mine is currently for sale. Too hi-fi.
Reeves 225: too expensive, too precious, and actually a pretty clean sounding amp unless you *really* push it.
HiWatt DR-201: I've never tried one. But lots of people say it's REALLY clean, and clean is not what I'm after.
Matamp/Orange/Electric Amp: Pretty trendy right now, but I've never played through them. Do they break up?

I'm seriously thinking about two V4Bs. Maybe have a custom headcase built with one stacked on top of the other. Or use one V4B preamp to drive two V4B output stages?

Or... SIX B15s! Yeeeessss. YEEESSSSSSSS! (evil Dr. Frankenstein voice.)

Jimmy, do I just have Ampeg-tunnel-vision? If so, is there any cure?

UncleFluffy · #11 08-31-2010, 10:43 PM

dummy load combined with speakers? ($20 worth of parts would probably do it)

specificially (assuming a 4 ohm speaker):

6 of these paralleled and placed in series with the speaker.

5 of these paralleled and placed in parallel with the speaker.

Bolt them on a solid chunk of metal because they'll be dumping the extra 100W as heat.

JimmyM · #12 08-31-2010, 10:46 PM

cost prohib, mostly.

not sure i'm telling you something you don't already know, but the fender tone stack in the d-180 may be to blame why you can't hear it live. it only boosts treble and bass and only cuts mids, so you can have a tremendous mid scoop unless you back down the treble and bass to almost off, like somewhere between 1 and 2 on the dials. i totally can't see the d-180 not working for you. i used one for a year and it's great and extremely loud.

JimmyM · #13 08-31-2010, 10:54 PM

ampeg tunnel vision? sounds like it. nothing wrong with liking ampeg, but i've always believed you should be able to get your sound out of anything you've got. obviously you can't get power tube grind out of ss gear, but i don't see any reason that d-180 wouldn't work. it isn't the same as the ampeg, but you should be able to get tones that work for you out of it. but if not, go get a couple v4b's and carry 130 lbs to do 2/3 of what 80 lbs will do

Passinwind · #14 08-31-2010, 10:58 PM

Quote:

Originally Posted by Ben Clarke

The only stress I can see (and I am not an expert) for the OPT if pulling output tubes is that the output impedance of the amp would go up (I think - Google around to check me), so you would need to be mindful of that.

One side effect of that is an increase in plate voltage supplied to the remaining tubes, assuming the original power transformer is used.

fu22ba55 · #15 08-31-2010, 11:05 PM

Quote:

Originally Posted by JimmyM

i totally can't see the d-180 not working for you. i used one for a year and it's great and extremely loud.

I love my D-180 for sure... but I always run out of headroom, and wind up switching to the V9.

Maybe if the D-180 could push a 2 Ohm load that would help. Or maybe I just need new power tubes...

C'mon, you're not interested in a Frankenstein'ed V4Bx2?

JimmyM · #16 08-31-2010, 11:16 PM

ok dude, let's take it easy...let go of the mouse...now slowly back away from the talkbass...

fu22ba55 · #17 08-31-2010, 11:21 PM

Quote:

Originally Posted by JimmyM

ok dude, let's take it easy...let go of the mouse...now slowly back away from the talkbass...

Hello... my name's Fu22. And I'm a Talkbass-a-holic.

Sartori · #18 08-31-2010, 11:31 PM

Quote:

Originally Posted by JimmyM

cost prohib, mostly.

not sure i'm telling you something you don't already know, but the fender tone stack in the d-180 may be to blame why you can't hear it live. it only boosts treble and bass and only cuts mids, so you can have a tremendous mid scoop unless you back down the treble and bass to almost off, like somewhere between 1 and 2 on the dials. i totally can't see the d-180 not working for you. i used one for a year and it's great and extremely loud.

This is pretty much what I do. Bass 1, treble pulled out at 4, mids at 10, and boosted on the graphic EQ.

And yes, it is ridiculously loud. I jammed recently with a friend who uses an SVT, and for the fun of it, we dimed both the SVT and the D-180 (two basses, two cranked tube amps... glorious doom). The SVT was a bit louder, but only just. The tones were quite a bit different, though.

I can't imagine a D-180 not being loud enough when playing through a nice big cab.

Sartori · #19 08-31-2010, 11:36 PM

Quote:

Originally Posted by fu22ba55

I love my D-180 for sure... but I always run out of headroom, and wind up switching to the V9.

Maybe if the D-180 could push a 2 Ohm load that would help. Or maybe I just need new power tubes...

C'mon, you're not interested in a Frankenstein'ed V4Bx2?

What cab(s) are you playing through?

I mean, I like my D-180 cranked, but it's too loud to do that except every so often. Depending on the output taps on the D-180, you could possibly have it converted to do 2 ohms. Not sure, though.

Also, you have V9?!

fu22ba55 · #20 08-31-2010, 11:36 PM

Quote:

Originally Posted by Sartori

I can't imagine a D-180 not being loud enough when playing through a nice big cab.

I've heard this on more than one occasion... and I do remember a time when sound men used to give me the hairy eyeball when using the D-180.

Maybe it's time for some new power tubes.