The Amp Garage

if you give it a thump and the problem come and\or goes its a mechanical issue or bad solder join....flex the pcb gently and in varios spots and wiggle the wires....if its not tube or mechanical start checking the power supply....and let the amp warm up a bit....heat changes the shape of things and ...

I appreciate that response......its a very subjective thing to compare differing tube types.....

I once saw a good article and project in glassaudio or audioexpress about that... very practical

The 6k6 at 250v with a 7.6k load can be biased to a 33ma. max dissipation makes around 3.4 W (ref. RCA RC-21) and is worth a try.....but is in no way like a little EL34....this is not to say it will sound badly for your application ....the 6BQ5 or EL84 which is sometimes called a miniature EL34........

everyone will have an prefferance.....the roll on my repair bench at the moment is .032 dia. 60\40.......my favorite is low melt 4% silver content......wts I think...its been a while.....it was special for gold contacts.... anyway.... Ive found that if the diameter is too small itll make a mess and ...

you can broaden your search.....if your transformer gives you an effective impedance of 7700 ohms with an 8 ohm load this is a ratio of 962.5 to 1
this give you a few choices of effective impedance

15.4 K at 16 ohms
7.7 K at 8 ohms
3.85 K at 4 ohms

happy hunting

hang on to those 6sl7 and 12sl7... and 6sn7 and 12sn7... they are becoming increasingly valuable as the NOS tubes become few....the 6k6 if I remember was intended for moderate power .....the design max plate voltage is 315....and application as a replacement for a 6v6 may not be the best....the 6k6 ...

Thank you... I hadn't chanced upon that yet....its a great resource....its nice to see a culmination of one man work....I was grateful the see the explanation of bias.... I've been thru the O-scope bit my self....it gives you some thing to look at.... its a good approach to voicing too....its easy t...

I'm curious as to how the third stage in a train wreck is percieved as a design element....although new to the forum I have been a tube and guitar amp freak/ builder for a couple decades and have hand built numerous rigs....this stage in a TW looks for all the world like a low gain buffer....with a ...

I completed a repair on an old princeton reverb that was brought out of storage in the worst conditions....after a some obvious fixes and eviction of insects it did a very similar problem....the fix was to clean the input jack..i saw another with that issue where the cause was one tube pin that was ...

I've wired a 50w with a paraphrase....it will have a much dirtier tone with less head room...but you will get a nice harmonic distortion with good tone color...the pentode pre will have a lots of gain potentialy.....try a simple treble bleed with .01 cap and 500k or 250k pot. first....it can be appl...