DIY Audio Projects Forum

Man, you're not kidding. That's a beautiful piece of art you've got there. Well done, sir.

Really? What problems did you notice with them? I'm using a 12AU7A and I haven't had any problems, other than the brightness that appears to be common with this amp. I upped the input caps (C1) to the largest film cap I could get in my local electronics store, 5.6uF, in hopes of passing more low end. I (stupidly) didn't think to also increase C3; oops.

like i said, for some "odd" reason, all my 12AU7a's sounded distorted and not focused. i know the only difference between 12au7 and au7a is the controlled warm-up feature in latter, but this is even after 10 - 20 minutes. i still have some minor issues in power supply, so i'm guessing this is not negative findings of the 12au7a tubes, but positives of those stronger spec'ed tubes i liked.

Have anyone of you here tried RCA 5963 Blackplate or Slyviania 5963 Greyplate?

I am currently using Audio Technica AD900, it's kinda bright sometimes. Detailed but not too analytical.
I would like to tone down some of it's highs, and make it to have more prominent bass, sweet sounding and nice imaging.

any tubes to recommend?

and yes apparently just like OP-AMPs valves have there own signature i just wish i had some more to try .

i would also like to try some Polypropylene input caps but they seem rather rare mind you its hard to get anything in the UK you Americans have all the good stuff lying around

Koogar[/quote]

haha... I am not an American... =P

I am from Malaysia... =P

My recommendation is the 6J5GT or 12J5GT ( most quiet, with metal housing ).

For the last couple of years i've tried different kind of tubes, but the best i've ever heard for this construction is the 6J5GT single triode ( open, detailed and very clear ). I solved the 6,3 V filament per tube, by serial coupling two of them, so they are feeded by the same battery supply, as the amplifier. Because it's a single triode, it's offcourse necessary, to use two of them, for a stereo setup.

6SN7GT or 12SN7GT double triodes, can also be used. ( 12SN7GT is near perfect, for this construction ).

Hey guys
i built one headamp for myself and its working fine my little brother wanted one to when he heard it.

But now i got problems i think its the lm317 on right channel as i turn the pot to adjust the bias i always get twice the V on left than on right channel.Nothing happens when i turn pot in right channel!

and i cant test it it wont make a sound tested with mp3 player computer etc

Any suggestions? is it the lm317?

i got some 4700uf 35v caps today and still there's distortion in low frequency. so, i think it might be something else that's causing the distortion. what else can it be? voltage is right at 12.4 - 12.8v with no noise whatsoever from the battery ps.

while assembling this particular one, i connected the PS wrong once and saw some smoke from either power-regulator or the transistor. it was just a few seconds and didn't seem to have damaged any of them....but do you think one of them might be damaged and causing the distortion?

i have put together another unit with fresh parts, and this time, i took extra care to not stress the parts too much with quick soldering and careful layout. thinking about building a separate power supply for this one, so it'll be a while until i can test it. if the new assembly has no distortion, i can conclude the first build's distortion as caused by power regulator or the transistor.

anyways, what do you think? can power regulator or the transistor be damaged and still function to pass great sound? other than low frequency distortion at high volume?

do post some pictures of the build please, then we can only comment...

the whole thing and close ups...

If you let out the "magic smoke," that's almost certainly the problem. I'd replace all four components: the 510s and the 317s. Smoke is never a good thing.