200 Watt SVT? How to do it?

[I Forget]

Is part of the great sound an svt makes when it's really pushed due to the output transformers being worked hard? I know with some guitar amps the low power mode doesn't sound the same only quieter, it sounds much brighter. It may not apply to an svt but you might want to make sure.

My 2c worth is see if you like the sound of a v4b being driven hard. If you do it's just a matter of having enough speaker to get the right volume. And you still have your svt unmodified for when you really need the grunt. Two amps has to be better than one.

One other thing, if you do go thru a pa you might want to experiment with a di run from a speaker out on the head, it sounds very dirty. You might like it, especially blended with a mic or a clean di signal.

 

[fu22ba55]

I'm still leery of just pulling out two tubes as Kevin O'Connor (London Power) suggested, so I asked him if it's harmful to the output transformer, and he said it is not harmful and to check their FAQ which reads as follows:

Removing tubes from a multi-tube fixed-bias output stage is never a problem. You can remove any number of tubes, and yes, that means you can take one tube out of a two-tube amp; one, two, or three out of a four tube stage, et cetera. This sounds heretical to techs stuck in the mire of convention, but it is something that has been known since tubes were invented.

The even-number tube extractions reduce power symmetrically. Neither the tubes nor the transformer will be damaged. Power will be reduced and so will frequency bandwidth - you will lose some bass and some treble. This is the point that switching the impedance selector to a less-than-load setting is supposed to correct, but it is completely subjective whether you should. The only 'should' of the matter, is do I like it this way, or do I like it that way?

In the uneven tube extractions, asymmetric power reduction occurs. Conventional thought says "the one tube on one side of the circuit will be trying to match the output of the two tubes on the other circuit half". This is wrong. The single tube can only produce so much power, and that's all it does. It doesn't melt down. The transformer does not blow up.

So, what's missing from conventional thought? The realization that tubes are "self-limiting power governors", which was stated in The Ultimate Tone (TUT), and explored in more detail in TUT2 and TUT3. TUT4 explores all of this in great detail.

In the end, you can pull tubes to reduce power, unless the amp is cathode biased - then you have to split the bias resistor. In any case, you do not have to worry about the impedance selector either.

So...

Does the SVT use a fixed-bias output stage, or is it cathode biased?

(I'm still waiting for *my* amp tech's response, since he's the one who's going to have to fix it when blow it up.)

P.S. I'm sick of all this amplifier crap. I'm gonna take up the drums. At least then if something breaks, you can see it.

 

[fu22ba55]

My 2c worth is see if you like the sound of a v4b being driven hard.

Love it. We've covered it twice already in this thread. Not loud enough. I would need to carry around two V4-Bs.

 

[Munjibunga]

What you need is a Peavey VB-2.

 

[fu22ba55]

What you need is a Peavey VB-2.

I appreciate the suggestion, and at this point I'll look into one. My brain is exhausted. But I do have a deep-seated phobia of Peavey stuff... I grew up in the 80's and back then Peavey stuff was, well..., looked down upon.

That said... those old 10"+10"+18" Peavey cabs sound great, even though they are awkward to move.

And don't tell anyone, but those two 18"s in my pic are Peaveys. Shhhhhhhh......

 

[taurus1]

Love it. We've covered it twice already in this thread. Not loud enough. I would need to carry around two V4-Bs.

I have a friend who played in an incredibly good (loud) prog metal band, he used a V-4B, his tone was killer.

how big are the rooms you play?

I think the idea of modding an SVT to put out 200w is an insane idea. I like insane though, insane is good.

 

[fu22ba55]

how big are the rooms you play?

Most rooms are 150-200 people these days, but it's not so much the size of the room as it is the size of the drummer's forearms.

 

[sanfordandsonny]

I had a 70s SVT running on 4 GE tubes unbeknownst to to me for 3-4 years
Years later it developed a transformer fault so I'm cautious to do the 4 tubes on my MTI SVT even though that would work really well for this band.
I am spoiled on the SVT/V4 preamp
That mid circuit is hard to replicate
I would say get two v4s and if you don't love it you'll lose little in resale and then you can have a v4 with the sensitivity adjustment and a v4b with the ultra low

 

[sanfordandsonny]

Also the MTI is a little bit more grindy
But I understand the topic is power tubes cooking

 

[fu22ba55]

I had a 70s SVT running on 4 GE tubes unbeknownst to to me for 3-4 years
Years later it developed a transformer fault so I'm cautious to do the 4 tubes on my MTI SVT even though that would work really well for this band.

Thanks. Legit anecdotal evidence usually trumps math in my book. But that's because I suck at math.

I am spoiled on the SVT/V4 preamp

That makes me all the more psyched about the Bluebeard Fuzz on its way to me as we speak.

That mid circuit is hard to replicate.
I would say get two v4s and if you don't love it you'll lose little in resale and then you can have a v4 with the sensitivity adjustment and a v4b with the ultra low.

The two-V4s solution is haunting me for sure. I'm not crazy about the look of the 27"-wide headcase, but if I switched to two 18"s full time instead of 15"s, then it would look killer. TL505s are 30.5" wide when laying on their side.

Also the MTI is a little bit more grindy
But I understand the topic is power tubes cooking

This is good info. If I were to do a serious mod to a working SVT, it would be to an MTI or USA-SLM, so it's important to note.

 

[ampegfuzz]

I just did a quick and dirty (no pun intended) with the ric, neck pup solo, tone off, my 1x15 cab, svt, and your settings. Started with a low volume then went to your volume. After that i tuned it back down and used a couple dirt boxes to try to get the same effect. as you would think close but not quite their. They sound cool though Sorry for the pick noise in the quieter parts, condenser picks up everything.

http://www.soundclick.com/bands/page_songInfo.cfm?bandID=993747&songID=9604348

 

[6810]

What you need is a Peavey VB-2.

That's what I thought when I first read this thread. Seems like a lot of overthinking is going on here...

 

[I Forget]

That's what I thought when I first read this thread. Seems like a lot of overthinking is going on here...

Yeah it does seem that way. And would a v4b into say an 810 really be too quiet for the gigs where an svt is too loud? I woulda thought it would keep up with most drummers. Well any drummer I would play with anywhoo.

 

[JimmyM]

wow, so you guys really think he's overthinking it? i think he's just gone plain crazy

 

[sanfordandsonny]

This coming week I am going to yank out two power tubes out of my MTI SVT for several reasons.
A. In the name of science
B. Just in case it blows up it saves y'all some $$$
C. It will stop me from buying a second v4 (or v4b)
D. There's that v4 for $350+shipping that has my soul yearning
Most important of all is that I wish could just recommend that someone buy a peavey this or a sunn 2000s model t that or traynor yba3 or mashall major
But I understand that none of those do it because
I've owned or played them all and while my wife liked her Sunn 2000s but is now happy with a gk200rb (we had to sell the sunn to help pay for the wedding.
I have not been able to be happy with anything but an ampeg when I want bowels to explode and people to die
Sure I've been dreaming of a Superbass but I am screwed and spoiled by ampeg and I think you are too.
A pair or v4s gives you alot of options to get sounds that you are looking for whereas many times a custom build forces you to only accept a very narrow range of options.
And what happens if you want to lets say have superfuzz going into a panning delay into channel one and channel two of v4 #1 and a subharmonic synth mono into v4#2?

The other reason is my MTI which was bought from a rental company from Texas has what I believe to be a linear taper volume pot where a log taper should be so between 1.5 and two I am too quiet or helllllla loud.

And if it works out I'll have extra room in the SVT to mount an internal nitro boost (the B from a morley PWB Cliffin' em all) that will melt preamp tubes.

My favorite fuzz into a Nitro-burning-boost into a quad of bleeding 6550s

 

[fu22ba55]

http://www.soundclick.com/bands/page_songInfo.cfm?bandID=993747&songID=9604348

Thanks Ampegfuzz for giving this a whirl. I appreciate the clip.

1) I liked the Masetro the best of the fuzz pedals. Had the same mid-bite I'm used to.

2) 1 x 15 might be a tough sell. It's taken me a while to find 15"s that respond well to the abuse and might of the SVT at 2:30. The TL-606s seem to be OK, but there are others out there that work well too. I personally find that older drivers (older JBls and EV15Bs and 15BNs) respond better to this brand of speaker-cone distortion.

In the clip, your poor 15" sounded like it was confused...a bit overwhelmed by the SVT and defeating itself. 2 X 15s might work better for the sound I was going for.

3) How did it feel to run your '73 SVT volume at 2:30? Beware... it can be addictive...

 

[fu22ba55]

wow, so you guys really think he's overthinking it? i think he's just gone plain crazy

I'm definitely asking a specific question. How to run a legit SVT at 200 Watts.

The earth is littered with 200 watt all-tube amps. I have two of them right now and will buy many more before I'm carried feet-first out of my house.

But it's a valid criticism. Why spend all this energy trying to break a decent SVT when I could just go buy a Traynor?

Well... because I'm asking HOW to do it. Not SHOULD I do it.

I will probably wind up with a Reeves 225, or Morgan MP200 or some 100% custom boutique amp.

But the question will still haunt me... How to run a SVT safely at 200 Watts.

 

[fu22ba55]

I have not been able to be happy with anything but an ampeg when I want bowels to explode and people to die

....Aaaannd, SIGG'ed.

I've never used a sig before, and will now never need to look for one again.

Thx.

 

[fu22ba55]

This coming week I am going to yank out two power tubes out of my MTI SVT for several reasons.
A. In the name of science

whereas many times a custom build forces you to only accept a very narrow range of options.

My biggest gripe with a custom build is that they have no resale value. I will be BURIED with the amp, so I better make sure I like it. If I spend $2000 on a 100% custom build, I wouldn't be able to get $1000 resale down the road since it would be an unknown entity.

If I buy a Reeves Custom 225... It would retain its value for a long time, (and sound pretty damn mighty.)

 

[Korladis]

I'm definitely asking a specific question. How to run a legit SVT at 200 Watts.

The earth is littered with 200 watt all-tube amps. I have two of them right now and will buy many more before I'm carried feet-first out of my house.

But it's a valid criticism. Why spend all this energy trying to break a decent SVT when I could just go buy a Traynor?

Well... because I'm asking HOW to do it. Not SHOULD I do it.

I will probably wind up with a Reeves 225, or Morgan MP200 or some 100% custom boutique amp.

But the question will still haunt me... How to run a SVT safely at 200 Watts.

I still think the simplest answer is to have a custom builder make you a 200 watt SVT clone.