First-Time Post / Bass Amp Questions

[Joe Viau]

Hey, guys, first-time poster here!

I'm glad I found this forum, I hang around Aron's Stompbox Forum quite a bit. I would like to build a bass amp but:

- I am ignorant, although I am planning on solving this by getting the Morgan Jones books on valve amps and valve amp building.

- I don't know where I would get transformers and stuff like that.

After doing some searching here, It seems that one of the more difficult things to do is to find transformers needed to fire up your amp. For example, if I wanted to clone an Ampeg SVT, the schematic has part numbers for the power and output transformers. How does one obtain those, and are there practical substitutions? How do you know what transformers to use? The power transformer SEEMS like it's pretty straightforward, but the output transformer has me baffled.

I know that the Jones books will help me understand what's happening, and I intend to be very careful with the high voltages involved. If anyone has tips or can point me to a FAQ I'd welcome the input.

Thanks in advance,
Joe

[Steve Conner]

Last time I looked, there was a guy on Ebay USA selling Fender 300PS output transformers for $100. If you wanted to make a bass amp, then buying an O.T. from a 300 watt bass amp might be a reasonable place to start. :P

I got one and managed to scrounge up a 500VA 1:1 isolating transformer to use with it as a power transformer. (We have 240V line here, so it works out.)

My main problem now is to find a chassis that can take these two heavy transformers without crumpling like a potato chip.

[ironradio]

Another first time poster here, greetings!

I am looking for an over 300W tube-bases bass amp kit. Is anyone aware of one? The largest one I have found is the TAD 150W kit.

Thanks for any info!

[drlowlow]

Hey. having ambition is a good thing. but if it is a your first amp build you may want to consider something simpler than an SVT. As for finding trannies to fit your need there has been a company I posted about in the past (I think in the post about parts for a B15N) that will take your specs to build a transformer. Either that or try Mercury Magnetics if they make a replacement for the SVT. I think that you might want to start with something a slight bit less complicated to get started (just my 2 cents worth here).

[Paleo Pete]

having ambition is a good thing. but if it is a your first amp build you may want to consider something simpler than an SVT

I agree, very good advice. I've been building and repairing computers for around 9-10 years or so and working with an excellent tech support forum online for the past 6 years. I always cringe when people on the forums start talking about their first try at building one by getting all the latest and greatest instead of shopping around for some older or used (and much cheaper) parts to build one for practice and experience. Why take chances with $1000 in parts when it really makes more sense to practice first on one built entirely from used stuff that may total $50-75...

I'm in the same boat really, I don't have the money right now for transformers and such, but I'd like to be able to build a 20 watter or so using a couple of EL84's I have (pulled from old CB radios) but I'm looking at much simpler amps to try it on first, single power tube, lower wattage, less complicated circuit to deal with. My biggest problem is schematics just don't make sense to me, I can work from a layout diagram, rebuilt my Super Reverb and Champ that way, but schematics are greek no matter how much I try to understand it.

Go for a much simpler amp to start with, I'm starting to think I might even go for a simple distortion pedal or something of that nature before tackling an amp.