• 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.

What amp to build? Push Pull, SE? thoughts?

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in addition, unless you want ot spend up on opts, you are stuck with the opts you have (presumably SE).

Just build. How much research do you need when you have all the major components and there are only two or three workable combinations to use them?

I'm with this. Let the junk box dictate. You see whatcha got and just need to arrange it in a sensible way.

Can't tell you how many cool builds I've done with this approach.

(My 12AT7 driving SE 12B4A for headphones or low power full-range speaks was a real winner. )
 
very close if the amp is not perfectly balanced (who is anyway?) .

It is not clear from this statement if it is the amp or the user is unbalanced.....maybe both?????

I've found in class A push pull triodes my personal nirvana.

The mentioned 300B P-P doesn't leave class A until 20 WPC. It starts to clip at 28 WPC, so it is mostly class A.

I have another amp using triode wired 7403's. It stays in class A until about 20 WPC but can do nearly 100 WPC. That one is still experimental, but sounds real good.
 
IMHO instead of PP vs SE I would consider output tube triode strapped vs ultralinear vs pentode. For SE I prefer pentode strapped.


For DIY I would consider SE topology as more convenient and suitable if audio source provides only single ended output especially.

Regarding topic's original subject I regret had missed cobalt core trafos from Magnequest

MagneQuest DIY: Kurt Strain's COBALT SET 45 Parafeed Dual Mono Amplifier

looks simple and very sweet.
 
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It is not clear from this statement if it is the amp or the user is unbalanced.....maybe both?????

Yes, it was an ambiguous statement (of the kind that makes people think). I'm fond of them (ambiguous statements or people who think? :D). Say the PI is perfectly balanced and the output transformer is not. Say the PI and the OT are perfectly balanced and the user is not. Many possibilities there. Heh,heh.
 
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if the amp is not perfectly balanced (who is anyway?)

George, to make myself more 'clear': "Water that is too pure has no fish". I don't believe in perfection; not in audio, not in life, not in anything. That's what I think anyway. So when people start talking about 'perfect' numbers, or perfectly balanced amps I feel like running away. A personal opinion of course, this is diyaudio, everybody has their preferences.
 
Hi, it`s been a while since I started this thread! I built a single tube 12AX7 stereo preamp yesterday and it sounds AWESOME. 100% quiet, massive gain, and sweet tube sound!

I have a 300V centertapped tranny, rectified with a 5Y3 tube. Total 400Vdc.

This is my hand drawn schematic :p

An externally hosted image should be here but it was not working when we last tested it.



As I said, it sounds beautiful and everything sounds alright except every 10-15 min of playing there is a sudden small quick "pop" in one of the speakes. What gives??

Im reading 220V at the plate. This is acceptable right? Any corrections or suggestions?

Thanks!
 
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She is a beauty! It sounds awesome. It`s single ended, EL84 wired triode. Someone might notice some champ components? It`s the same transformer found in modern fender champs, as well as the tiny OPTs`. I glued some piece of oak on each side and stained it deep mahogany red. Me gusta.
Thanks for the input folks!

An externally hosted image should be here but it was not working when we last tested it.
 
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