A Super-Simple 6DJ8 Headphone Amp - Page 27

Just soldered up my board. I replaced 2sk310 with IRL510, and use CV5358 instead of 6DJ8. However, the output gives around 100mv AC and it does not work. Anyone can help? PS: I was buying resistors in a combo, so all of them are 1W rating, will that be the problem?

I have tried the 1K trim pot so that pin3 on LM317 is 15v, however, after 13ohm and 15ohm, it gives 8v instead of 6.3v which is the tube required. can anyone suggest a solution?

Finished mine, just waiting for friend of mine to do some drilling for box.

Used Panasonic FC caps 1 x 3900uF, 2 x 1800uF, 2x 470uF and Roederstein MKT1813 1uF with EH 6922 tube

Did few minutes test driving with some really old headphones and seemed to work well and the sound was awesome ;)

Has anybody cut the trace feeding B+ to the 6DJ8 and fed it with higher voltage?  With a 24v supply feeding the 6DJ8, how much plate voltage is there even (10-15v max??)

Incidentally, with the voltage regulator sitting under the fet, you could probably jack the voltage up on both stages. 

The 6dj8 is DC coupled to the output FET. you cant really bump the plate voltage on the tube without increasing the voltage supply to the FET too. 

Im not sure if the heat-sinks are large enough to handle the extra heat, or if the various caps are rated adequately, but it would probably be a fun project for someone who wanted to go a little wild with it. 

What happens if instead of a 100k you use a 50k or a 10k one ?

anybody tried using this as a preamp? can i wire rca outs parallel to the headphone jack without worrying about hum?

and do all resistors get hot? i'd like to sneak in carbon comp resistors wherever i can if i can avoid the value drift. 

I design my own PCB variation of this amp

Tube's socket is on top side, all other parts on other side. PCB are double sided, designed for Alps Blue Velvet pot, 6.3mm headphone socket, large power and output caps, bias trim pot.

In my prototype amp FETs and LM317 are mounted to enclosure, however vertical heat sink can be used.

Quote:

Originally Posted by Zigis 

I design my own PCB variation of this amp

 

 

 

Tube's socket is on top side, all other parts on other side. PCB are double sided, designed for Alps Blue Velvet pot, 6.3mm headphone socket, large power and output caps, bias trim pot.

 

 

In my prototype amp FETs and LM317 are mounted to enclosure, however vertical heat sink can be used.

WOW, nice case.

Quote:

Originally Posted by Zigis 

I design my own PCB variation of this amp

Great job! Have you got a couple of PCBs to spare?

Boards are double sided, with ground plan, fixed with 2 screws near tube socket and pot's and headphones jack's nuts to front

I have few board left, if anyone wants to try it.

1 PCB shipped are 10 Euro

Thanks ludoo, yes I have few

Quote:

Originally Posted by sashaw 

WOW, nice case.

Thanks, actually it is fast prototype, made from piece of aluminum U profile, lot of scratches, some drilling errors. 

Idea is - black anodizing finish and side panels from good wood, walnut or bubinga. 

I made it about year ago, project stopped because of lack of time and I can't find good anodizing service locally. Maybe I go to powdercoating route.