"Bass players don't need tubes."

[Psycho Bass Guy]

Amen brother! I loathe SVTs. I'm forced to use them at rehearsal studios, and cannot get a decent sound out of them to save my life. And I have no problems getting amps to sound good.
They just have awful EQ stacks. There's a big hump around 250Hz that you can't get rid of, and the low end is intentionally rolled off. The mids sound boxy.

...an "SVT" is not an SVT in every case. THE SVT is the first through fourth generation, two-channel, all tube head. Though there are various minor differences between vintages and manufacturers, their basic sound is very clean and very accurate with tons of low end, and a very large amount of gain should you desire it. The preamp only has the low mid bump if you put it there.

Later SVT Classic amps are a whole different ball of wax, voiced exactly the way you describe... and that's not even beginning to take into account the various s/s amps that have carried the SVT badge or the various models of SVT cabinets which entail a science unto themselves. Unfortunately age and disrepair have thinned backlines of REAL SVT's and the ubiquitous black stack on so many stages is a poor representation of a great sounding amp and cabinet. Even many of the real deal don't sound good because they're out there limping along held together by hack guitar amp techs.

Personally I have a Mesa 400+, which is a very nice sounding tube amp.

I have one too, and it IS a great sounding amp, but nowhere near clean enough to suit me in stock form. It's also based on the classic Fender Bassman tone stack: big round lows, scooped mids and present but tame highs. IMO if you want to hear that amp at its best, swap its driver 12AX7 for a 12AU7 and be amazed at the amount of clean power it suddenly becomes capable of putting out. It gets tones no SVT ever could, however it's also much easier to lose in a dense stage mix if you play loud.

What I expect from an amp is to hear my bass the way it sounds DI'd into a board, with a little extra girth.

I feel the same way to a point, however, what most people think of as "accurate" or "flat" is usually anything but a truly accurate bass sound. I do, however, also love most older Trace Elliot amps, tube and s/s.

[SGD Lutherie]

...an "SVT" is not an SVT in every case. THE SVT is the first through fourth generation, two-channel, all tube head. Though there are various minor differences between vintages and manufacturers, their basic sound is very clean and very accurate with tons of low end, and a very large amount of gain should you desire it. The preamp only has the low mid bump if you put it there.

See, that's the way I remember them, and recently used this one for a recording session:



It sounded nice and clean.

All the new ones sound like ass, and not good ass.

Later SVT Classic amps are a whole different ball of wax, voiced exactly the way you describe... and that's not even beginning to take into account the various s/s amps that have carried the SVT badge or the various models of SVT cabinets which entail a science unto themselves. Unfortunately age and disrepair have thinned backlines of REAL SVT's and the ubiquitous black stack on so many stages is a poor representation of a great sounding amp and cabinet. Even many of the real deal don't sound good because they're out there limping along held together by hack guitar amp techs.

Now interestingly, there was an article on the SVT in BassGearMag not too long ago, and the designer Bill Hughes said they voiced it that way to work on large stages. So they roll off the lows to not get boomy, and then boost at 250Hz to make up for the missing bass. The Ultra-Lo switch notches the mids. They showed a frequency response graph from a 1974 SVT and showed how you cannot set it flat.

Quote from Bill Hughes:

I had previously developed a style of equalization for bass while working as a freelance recording engineer. Cranking up a lot of low end boost was never a good idea when your target is vinyl. rather, removing the lower odd-order harmonics (as the SVT was set up to do) does way more to give the right illusion. I guess this is why bass amps with graphic EQ have fallen from vogue.

Still, I don't remember the old ones sounding so bad. Maybe they exaggerated the EQ curve?

I have one too, and it IS a great sounding amp, but nowhere near clean enough to suit me in stock form. It's also based on the classic Fender Bassman tone stack: big round lows, scooped mids and present but tame highs. IMO if you want to hear that amp at its best, swap its driver 12AX7 for a 12AU7 and be amazed at the amount of clean power it suddenly becomes capable of putting out. It gets tones no SVT ever could, however it's also much easier to lose in a dense stage mix if you play loud.

The only time mine would break up is if it was really cranked. And then I agree with you. When I bought it, I also had a GK 800RB, and that mopped the floor with the Mesa in terms of sheer volume. I use an 12AU7 in my BlueTube for the same reason, so I'll give it a try in the Mesa. Also, unfortunately when I bought the Mesa it was retubed with Ruby Tube power tubes, and Sovtec preamp tubes. I think the power tubs are too soft sounding, but it's an expensive proposition to retube that amp. It has been sitting unused for the last 10 years since it needs some minor repairs. I was using the GK in the mean time, and then I traded it for the Trace.

I feel the same way to a point, however, what most people think of as "accurate" or "flat" is usually anything but a truly accurate bass sound. I do, however, also love most older Trace Elliot amps, tube and s/s.

My thing is I want to hear the sound of my bass. Then I can take it from there. I like how the bass sounds direct, and the amp adds to that. My s/s Trace is one of the old ones. It's a great sounding head, and really loud for 150Watts.  I've been meaning to check out some of the newer Trace gear.

Recently I tried out a couple of the new Hartke amps with the tube preamp. I liked it, but felt it lacked the warmth I get from the BlueTube.

[Psycho Bass Guy]

recently used this one for a recording session:

That's actually one of the new "Reissue" models produced by Loud Technologies. From all accounts they do sound pretty much the same, but internally they're nearly impossible to service at all.

Now interestingly, there was an article on the SVT in BassGearMag not too long ago, and the designer Bill Hughes said they voiced it that way to work on large stages. So they roll off the lows to not get boomy, and then boost at 250Hz to make up for the missing bass. The Ultra-Lo switch notches the mids. They showed a frequency response graph from a 1974 SVT and showed how you cannot set it flat.

I have that issue. They also couldn't get moe than 240 clean watts out of it. I like those guys, and I appreciate what they're trying to do, but just changing their methodology slightly would yield drastically different results, like Mythbusters. Here's a dirty little secret that really stirred up the kids on TB: WIRE doesn't have a "flat" frequency response. Since you're familiar with pickups, it's easier to relate to you. Just like output impedance affects a tube bass amp's performance, so too does the input impedance. If the magazine had used an inductive coil at roughly the average output imepdance of most passive pickups and not just a padded broadband voltage, you'd see the preamp AND power section is actually VERY flat. I also suspect that amp could have used some good TLC, too.

Also, unfortunately when I bought the Mesa it was retubed with Ruby Tube power tubes, and Sovtec preamp tubes. I think the power tubs are too soft sounding, but it's an expensive proposition to retube that amp.

It's doubtful that the tubes themselves need replacing. Tube replacement is THE single most exaggerated aspect of vintage amps I've ever encountered. Power transistors aren't rated for any more life than power tubes; Aspen Pittman just convinced everyone years ago that they needed to buy his Groove Tubes far more than necessary and the BS has only snwoballed from there. A simple bias adjustment would probably tighten up the sound of your output section and make your amp sound better than new.

[Chris P.]

Very interesting posts guys!! Thanks!

[SGD Lutherie]

That's actually one of the new "Reissue" models produced by Loud Technologies. From all accounts they do sound pretty much the same, but internally they're nearly impossible to service at all.

Ah! Well it sounded pretty good. I wasn't playing it very loud, and half my signal was going through a Demeter tube preamp (which I liked better). I also preferred the tone of the Ashdown, which was plugged into the right SVT cab. The cab on the left is an old one.  Generally I don't use amps in the studio, but the studio owner was excited about his amp and wanted me to use it. He also wanted me to pose with it.  lol

I have that issue. They also couldn't get moe than 240 clean watts out of it. I like those guys, and I appreciate what they're trying to do, but just changing their methodology slightly would yield drastically different results, like Mythbusters. Here's a dirty little secret that really stirred up the kids on TB: WIRE doesn't have a "flat" frequency response. Since you're familiar with pickups, it's easier to relate to you. Just like output impedance affects a tube bass amp's performance, so too does the input impedance. If the magazine had used an inductive coil at roughly the average output imepdance of most passive pickups and not just a padded broadband voltage, you'd see the preamp AND power section is actually VERY flat. I also suspect that amp could have used some good TLC, too.

Good point. Still, some of the reissues sound exactly like they had shown, and also the way Bill Hughes had alluded too.

It's doubtful that the tubes themselves need replacing. Tube replacement is THE single most exaggerated aspect of vintage amps I've ever encountered. Power transistors aren't rated for any more life than power tubes; Aspen Pittman just convinced everyone years ago that they needed to buy his Groove Tubes far more than necessary and the BS has only snwoballed from there. A simple bias adjustment would probably tighten up the sound of your output section and make your amp sound better than new.

I'm sure you are aware that the 400+ is fixed bias. This is why Mesa wants you to by their tubes. Not saying that the bias couldn't be adjusted, but not easily.

The guy I bought it from runs an amp repair shop (Dave's Sound Repair in Whippany, N.J.). He's a good guy and generally knows what he's doing. I guess at the time the amp had Groove Tubes, and he hates Groove Tubes. He also installed some kind of protection circuit on the power tube grids. They have fuses and LEDs to let you know if you blew a fuse.

Different tubes do sound different however. I tried a few different of 12AX7s in my BlueTube, and before switching to a 12AU7, I used an old Sylvania tube, which sounded best to me.  The amp needs a little servicing. Two pots got broken off (which they didn't use nylon shafts!), and then shortly after that it started blowing it's main fuse, so I stopped using it until I could get it looked at, and then just never got around to it. But now I want to start using it again.

A funny story that goes with that amp is that I saw the head at Dave's Sound one day, and had been thinking of getting a tube amp. So I ask about it, and he says "well if you want it you better buy it because some guy was asking about it and might come back tomorrow. So I bought it.  A week or so later I see a classified ad for a Mesa cab, so I go to check it out. The guy tells me he was looking at a 400+ at Dave's sound, but someone else bought it, so now he doesn't need the cab... You should have seen the look on his face when I old him! It's a great sounding cab too. Loaded with Eden speakers.

[dadagoboi]

Works for me in a wide variety of applications

[SGD Lutherie]

Works for me in a wide variety of applications

That's the Demeter preamp I used in the studio. That thing sounds really nice!   

[ThunderBucker]

But only *guitards* get these special tone adjustments on their Demeter amps....

[OldManC]

Ha ha, I wants me some terble!

[Dave W]

Ha ha, I wants me some terble!

Bass players don't need terble. 

[dadagoboi]

We're terble enough without it.

[Bionic-Joe]

I Love the early 70's Hiwatts. Very powerful amp. VERY CLEAN and just enough bite to rip someone's head off. I got some great info on how to dial it in from Tom Petersson that unfortunately I cannot reveal. Secret.
   As for Ampegs...almost every studio in Chicago has a B-15N.....great recording amp...I like the original 1969-71 SVT heads and Squareback cabinets.
   But.....if you ever get the chance...try a 200 watt Hiwatt through a squareback...It will freakin rip your head off!!!

[dadagoboi]

The Demeter VTBP-201 Preamp is based on the front end of one of Pete Townshend's Hiwatts, possibly the reason for the '201' designation.

[Highlander]

The 41 year old DR103S and 41 year old Marshall 4x12 slope cab I have work great for me. and as Bill noted, ooh that smell...

But also running a MAG300 combo with 4x10's so willing to play through anything that works, and both setups work for me...

[Psycho Bass Guy]

Good point. Still, some of the reissues sound exactly like they had shown, and also the way Bill Hughes had alluded too.

I remember the first time I ever fired up an SVT. I had just bought it with the money that I had saved to buy an engagement ring for a girl who said yes and then bolted. She did me a huge favor.

I'm sure you are aware that the 400+ is fixed bias. This is why Mesa wants you to by their tubes. Not saying that the bias couldn't be adjusted, but not easily.

It's nowhere near as difficult as you might think. Matter of fact, installing a variable adjustable bias control isn't even that big of a deal. Mesa does more than its own share of BS marketing, especially concerning tubes. When bias cannot be adjusted for aging, then tubes have to replaced any time they age outside of the bias voltage setting which makes them appear to be losing power and dying, when in fact, it's just a perfectly normal part of their operation. Typically after around a hundred or so hours of hard use, power tubes will need their bias reduced to maintain their rated output power. It's not because they're inferior; their cathodes have simply used more of the electrons deposited on the surface of the cathode and it takes a slightly higher voltage to energize the interior of the tungsten material of the cathode. Transistors do it too, but for different reasons, and since their operational voltages are orders of magnitude smaller than tubes', the loss of performance is much less noticeable.

The guy I bought it from runs an amp repair shop (Dave's Sound Repair in Whippany, N.J.). He's a good guy and generally knows what he's doing. I guess at the time the amp had Groove Tubes, and he hates Groove Tubes. He also installed some kind of protection circuit on the power tube grids. They have fuses and LEDs to let you know if you blew a fuse.

Screen grid fuses usually are there to prevent runaway from oscillation caused by a number of things. 400+'s don't run voltages high enough to justify such a measure, not to mention that 6L6GC's are generally not prone to screen oscillation anyway. If the amp ran at higher voltages and used EL34's, whose internal geometry and higher plate resistance makes oscillation more likely, I could see doing that (though I wouldn't.) It will help to keep the amp going in case of misuse (improper output loads, etc) but it would compromise the sound of the amp, limit its output power below rating, and could cause a bunch of other problems.

Groove Tubes never made their own tubes anyway, though they often implied or outright lied otherwise, nor were their ratings any real kind of operational parameter. They just bought various tubes wholesale, ran bias tests on them, and grouped simlilarly biasing tubes together. They also had a good algorithm which could predict how the tubes would age based on their cathode properties and grouped together tubes that they purposefully knew would become grossly mistmatched as they aged, typically right as their six month warranty expired.

Different tubes do sound different however.

That's a major understatement. Even among the same type, different makes and variations can have enormous variations in performance.

The amp needs a little servicing. Two pots got broken off (which they didn't use nylon shafts!), and then shortly after that it started blowing it's main fuse, so I stopped using it until I could get it looked at, and then just never got around to it. But now I want to start using it again.

Depending on which pots broke, that might be the problem, but not necessarily. You don't want nylon shafts for most amps anyway. If a pot breaks, it's better to short potentially dangerous voltage to the chassis case/ ground lug of the power cord.