• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Tube Amplifier Kit?

Hi!

I am looking for a tube amplifier kit, as I really want to built one and get some experience soldering, etc.

I'd prefer that it's a stereo one, and 10-15 wpc is fine.

Can you give me links to anyplaces that might have a kit like this?

I'd like to keep costs under $250.

Thanks!
Henry
 
Henry,

The low cost kit Sal linked is going to come up short on power. IMO, those wood plank and PCB amps are barely better than toys.

May I immodestly suggest you peruse the SAGA of "El Cheapo''. You should be able to get 12 very honest WPC using ultralinear wired O/P tubes and come darn close to that $250 cost. Build with Edcor CXPP25-6-7.6K O/P trafos.

BTW, if a CDP is the source, you don't need a preamp with "El Cheapo". ;)
 
Thanks for the help and esp. the links, guys!!!!

Why isn't the amp that Sal suggested a very good one?

If I bought it, I'd probably buy the glass/metal cage for it just for good measure--so the wood breadboard would be unnessessary.

I have a couple old Pioneer CS-99 speakers that are 80 watts each--they are pretty efficient. would Sal's 8wpc amp drive them OK?

also, I'm using a CDP/tuner as a source. I may use a preamp though.

Overall, I probably wouldn't use it much at all. I just want it to build, as I'd have a ton of fun building it. I don'd want to spend a ton of money (i.e., $400+) on an amp I would build and hardly use. I already have spent over a $1000 on my main amplifiers (S/S) and they are my daily drivers. If I ever wanted a tube amp to use regularily, I would save up and buy an expensive one.
 
theblackknight said:
that ST-35 is pretty expensive, but I may end up going with it.
....Is there a possible way to find a schematic and just build the amp out of ebay'ed parts?

If you are going to go that route you would do much better to do a variation on Eli's El Cheapo.

We did a 4W class A variation with EL84 and it is really an eye opener. This coming WE we will be using it as a refernce to evaluate the sonics of some amps from $1000-$2000 and within its limits i expect it to show up the shortcomings of the commercial kit.

dave
 
that "saga of el cheapo" really sounds intrigueing. I think I will go with it!

I'd like to be able to use EL-84's if possible because I have 2 Mullard EL-84's around here looking for a better amp!

I also have a Mullard 12AX7 that I could use.

I will reread the thread more closely this weekend and see if I can better understand all the "tech talk" in it. Then I will post back with any decisions/questions.
 
theblackknight said:
that "saga of el cheapo" really sounds intrigueing. I think I will go with it!

I'd like to be able to use EL-84's if possible because I have 2 Mullard EL-84's around here looking for a better amp!

I also have a Mullard 12AX7 that I could use.

I will reread the thread more closely this weekend and see if I can better understand all the "tech talk" in it. Then I will post back with any decisions/questions.


You need 2X tightly matched power tube pairs (4 tubes total) to build an "El Cheapo".

Even if you had 2X Mullard 12AX7s (1 per channel), the high Rp and low gm makes the type a poor choice for the differential (LTP) splitter/driver used in EC. The 12AT7 was selected for more than 1 good reason.

The tubes you already have might make a nice SE pentode amp. However, 5 WPC is all you get. So, speakers at least 95 dB. efficient are in order. Also, a "flat" impedance curve is necessary.
 

jamie1107

Member
2008-01-31 1:17 pm