#1
so my friend has a Sunn Beta bass head (100 watts @4 ohms) it sounds amazing, but he wants more wattage (300-600) he asked me to build him a power amp so he could use the beta bass as a preamp.

will a tube power amp make a tone difference from a solid state power amp since the preamp will be solid state?

any recommendations/schematics?

also wanted to include an xlr out on the power amp so he could go direct to the board from the preamp
#2
You don't really come across as having a whole lot of confidence about this whole project. There's plenty of tube power amp schems to be had by googling, just copy a SVT power section.
600 watts is going to be a lot of tubes. 12 KT88s or 24 6L6s for an example, so maybe just stick with 300.
DI outs usually come from the preamp too.
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#3
Yes tubes will make a diffrence in sound.

Look at the Line 6 Spider, it is a well hated amp. Put a tube power-amp on it (Spider valve) and you have an amp that sounds pretty damn good.
The same with the Peavey vyper, the tube poweramp in the Vyper tube makes a huge diffrence in sound.
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#4
tube it is then. this would be my first amp build, im a little concerned but confident i can do it. i know DI outs come from the preamp, but the Beta bass doesnt have one, so i would just be mounting the jack on the same chassis that the poweramp is in, before the poweramp.

i was hoping to stick to a design with less tubes, was considering doing the svt or beefing up a v4 power section though
#5
Have you ever worked on or wired tube amps? They are deadly if you make a mistake or simply touch it the wrong way or with two hands. Building a tube amp is expensive, why not just buy one on ebay? Also tubes do color tone, but the sunn is already SS, and the power amp at say 300 watts needs to be very cranked to reach any amount of power tube saturation that would really color the tone, and prolonged cranking kills power tubes, and 8-12 tubes at $15-$50 a piece are expensive. Also does the sunn allow use as a preamp? Overall, a cheap SS power amp might suffice. IF you really want the tube amp tone, at the cost of building a 300 watt power amp, you're close to the cost of a used SVT or other tube amp already.
#6
ive worked on high wattage solid state heads (including the beta bass), but nothing tube yet aside from taking a look at another friend's bassman. i know it will be expensive. the sunn does have a preamp out that shuts off the poweramp i believe. if not i could always rig it up to.
#7
Just read all you can about tube amps and safety, they are nothing alike, and any mistakes can easily destroy the components. But do it and if it's cool share the schematic. I still think a SS power amp would be a simpler answer and wouldn't be bad sounding.
#8
I come down on the side of science, and say that tube power-amps sound no different to solid state amps when run clean. The various different "warmth" and "chime" sound characteristics that are associated with them are mostly placebo induced.

Seriously, people have done studies showing that when people don't know which amp is which, they can't reliably tell the difference. They even do tests where a switch (that isn't wired to anything) is placed on an amp, and tell the test subjects that this switch changes the power section from SS to tube - and almost all of them swear that they can hear the difference.

Just my 2 cents.

If they are being overdriven, however, then there genuinely is an audible difference.
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#9
thanks for the answers so fay guys! i dont think he intends to overdrive it much, but possibly enough to get some saturation.

also, because i intend to make it a separate unit, he could eventually run a tube preamp into it, or have me build him a preamp for it, which is why i figured tube would be best. thoughts?
#10
Quote by Killerfridge
I come down on the side of science, and say that tube power-amps sound no different to solid state amps when run clean. The various different "warmth" and "chime" sound characteristics that are associated with them are mostly placebo induced.

Seriously, people have done studies showing that when people don't know which amp is which, they can't reliably tell the difference. They even do tests where a switch (that isn't wired to anything) is placed on an amp, and tell the test subjects that this switch changes the power section from SS to tube - and almost all of them swear that they can hear the difference.

Just my 2 cents.

If they are being overdriven, however, then there genuinely is an audible difference.


Couldn't have said it better, and emphasizes my point of unless you're playing loud like volume at max or close to it, your tube's and build are just a money funnel. When playing on a tube amp, preamp tubes distort at any volume with gain and volume. Power tubes take full volume and gain saturation to make any real tonal change and even then, the preamp tubes make most of the "overdriven" sound. And to add it again, building is expensive, keeping tubes up is expensive too, and playing at full 300 watt volume, you're either blasting wayy too much volume to get tube tone, or not getting it. The tones people like from tubes are when the tubes are actually ceasing to function properly, this decreases their life. A guy at a shop recently mentioned a guy paying $500 for a retube of his mesa amp.
#11
the money side of things is really up to my friend, im more concerned with what will make more sense, so sounds like solid state will for this application. i was also thinking of including a graphic eq before the poweramp section, thoughts?
#12
why does he want it built? If you just want to experiment ok, but it's never cheaper, and rack gear is insanely cheap right now. you could get a used power amp and graphic EQ for pennies compared to you buying, designing, wiring and machining your own stuff.
Also rack gear can be fit into a rack!
I hate to be the downer, but I've asked similar questions before, and the short answer is, if you have to ask, it's not a good idea.
#13
he wants it built so it can be custom made for his needs, i do want to add some level of experimentation, and he is aware and supportive of this. i would probably build it so that it could be rack mounted. and even if i don't end up building it, or don't end up building it for awhile, i'm just curious