How about bass tube amp

[kldguitar]

About bass tube amp.
which company it?
what difficult to make it?
what tube used in bass amp commonly?
how many larger power commonly?
http://www.kldguitar.com

[mooreamps]

This is one of my projects that's on a back-burner right now. But, at some point I'm going to use my 813 project as a 200 watt bass amp. I'll also be using my new TMB tone stack along with the 6SL7's to support to low end.

-g

[Bruce / Mission Amps]

This is one of my projects that's on a back-burner right now. But, at some point I'm going to use my 813 project as a 200 watt bass amp. I'll also be using my new TMB tone stack along with the 6SL7's to support to low end.

-g

I got the tip of my finger blown off with an amp running four 813s at 3000vdc. I hate them things and the ass who disengaged the safety switch form the RF deck cage.

[black_labb]

and i thought that my holden/wasp was high voltages with the 700vdc.

changed some caps to get more from the low end and it sounds great for bass. huge output tranny too.

[mooreamps]

Well, I wasn't going to run plate voltage quite that high, but diffently not a beginners project either. It will be interesting to get the feedback on this one to see what the bass players think of using such a big pair of output tubes in a rig like this.

-g

[black_labb]

sounds good. what are you using for the ot?

[Enzo]

I think we have wandered.

kld, there are several large tube bass amps.

The AMpeg SVT is still being made by Loud Technologies. 300 watts based on six 6550 tubes. They make several different SVT models, the SVT-CL is the all tube version.


Peavey used to make a 300 watt amp based on eight 6550s called the Classic 400. They have not made it in a long time, but the schematics can be requested from parts@peavey.com

Fender made the Bassman 300, 300 watts based on six 6550s.

You could make it based on other tubes than the 6550, but the 6550 is reliable and available everywhere, and in current production. And the voltages they use internally are not much higher than in guitar amps.

Many players like the amps, but they are extremely heavy because of the very large transformers. Most players do not want to carry an amp head that weighs 85 to 120 pounds. (40-55kg)

A large tube amp should not be more difficult to make except it will be larger, the chassis will need to withstand the weight. This is extra important during transportation. The SVT for example has two power transformers, one for the heaters, and one for everything else.

The power supply will have to be heavier duty, since the low frequencies will demand more from the filter caps.

[Steve Conner]

http://www.chambonino.com/construct/const9.html
http://www.chambonino.com/construct/const8.html

[black_labb]

those are some huge amps, im curious about those el36 tubes. in the second one. seems like a cheapish high powered amp once you get a suitable transformer.

reguarding the original question, the difficulty with a bass amp is really just the higher power. the circuitry can be quite simple (there wont tend to be any effects, just the preamplifier, tonestack/volume and the output. the difficulty is getting big enough transformers to push enough clean power and have a good frequency response. that and the tubes are quite expensive. the power transformer will have to be quite bulky as well, as there tends to be higher voltage (depending on the tubes) and alot more current.

the reason they arent being made by as many people as valve guitar amps is the cost involved in the transformers. some people dont like carrying such a big amp around as well, but thats the consumers choice.

[mooreamps]

sounds good. what are you using for the ot?

Currently I have a 100 watt Hammond, thinking at first it was going to be an electric guitar amp. Yes, the chassis wieght on this one will be on the heavy side, mostly for not specing some of the parts correctly. Well, you live and learn.

But, I really did want to bring up a high power amplifier using this type of power tube. I realize doing a bass amp well is not an easy task to undertake. So, I'll take whatever feedback I get off of this first one, and then work those issues as they present themselves.


-g

[black_labb]

cool, im thinking of doing a 100w amp with tremolo/vibrato (fender made me get mixed up, the one where the volume fluctuates).

i think that a throbbing distorted bass would be really cool. would be a good head for guitar too.

[David Schwab]

I think we have wandered.

kld, there are several large tube bass amps.

The AMpeg SVT is still being made by Loud Technologies. 300 watts based on six 6550 tubes. They make several different SVT models, the SVT-CL is the all tube version....

Don't forget Mesa!

I have a Mesa Boogie Bass 400+, 500 Watts! 12x6L6, 4x12AX7

And yeah, it's too damn heavy, so I don't really use it anymore.

It's a much nicer amp than an Ampeg, which have awful tone stacks IMO.

[Enzo]

Yep forgot that one. List wasn't meant to be all of them, just examples

[Gtr_tech]

I think we have wandered.

kld, there are several large tube bass amps.

The AMpeg SVT is still being made by Loud Technologies. 300 watts based on six 6550 tubes. They make several different SVT models, the SVT-CL is the all tube version.


Peavey used to make a 300 watt amp based on eight 6550s called the Classic 400. They have not made it in a long time, but the schematics can be requested from parts@peavey.com

Fender made the Bassman 300, 300 watts based on six 6550s.

Don't forget the Fender 400PS. Rich Koerner swears by those. The Traynor Super Custom Special (6KG6s) is nothin' to sneeze at either.

[Steve Conner]

While we're wandering, did anyone else notice that a 100 watt Hammond OT is completely wrong for a pair of 813s?

If you run it at its intended B+ and impedance match, you'll only get 100 watts. The 813s need at least 1500, maybe 2000 or 2500V to get them raging. In this case, the output transformer will start to saturate below something like 200Hz, since it's having to eat so much more voltage than it was designed for. I predict it will sound like crap, and arc over and catch fire within a few minutes.

If you really want to take advantage of these tubes, you need a 20lb custom OT, a plate transformer salvaged from some ham radio boat anchor, a wall of 4x12"s and no neighbours