[texanater]

Greetings All,

I just completed my first electronic DIY effort and got really really close.  I made a bugle with much help from Tom P and used many of his suggestions regarding component upgrades.  I'll post more later about Tom, but he was amazingly nice and helpful, and that is an understatement. 

The bugle includes the power supply.  The upgrades include the Russian caps on C1 and C4, a better op amp, the 47.5 Kohm resistors are the vishay tx 2352 and others.

Long/short - the right channel initially sounds great then fades after 5+ minutes of play.  When it fades it initially gets some distortion which increases as the over all volume decreases over about 15-20 seconds.  I can turn the unit off and wait a few seconds, then turn it back on and the process starts over.  If I turn it back on shortly after, the process is much shorter.  Sounds like a capacitor to me but how do I trouble shoot?  I have a basic onderstanding of circuits but strictly basic.

Thanks for your help!

Nate

[PatOMalley]

that could be a bad solder joint.
i had same thing happen on an output cap.
the lead was soldered into it's hole but not touching the metal side of the hole. It just in it's pool of solder. After it heats up it separates or loses contact even though physically it looked solid.

All i did to fix was to heat up the joint, pushing the lead against the hole side, and let the solder cool.

not sure if this IS what is going on in your case but it sounded similar so I thought I would pass it along.

[texanater]

Thanks Pat for the suggestion.  I reseated the caps as best I could with no change.  I then soldered jumpers from the cap leads to the next part of the circuit they connected to with no change.  I'm stuck!

Nate

[texanater]

I figured it out.  It wasn't the caps but rather what they were connected to.  The 47.5Kohm at R15 or R33 or whatever weren't seated.

Up and running now for a whole album so I bet that was it.

Thanks all, especially Pat!

Nate

[Brinkman]

The bugle includes the power supply.  The upgrades include the Russian caps on C1 and C4, a better op amp, the 47.5 Kohm resistors are the vishay tx 2352 and others.

You want to keep the OPA2134 op amps in the first two positions as the EQ was voiced around those particular op amps. The third position is the one to roll op amps in and out of.

[texanater]

Thanks Brinkman, thats exactly what I did.  The first two positions were the 2134 and the 3rd was the 2604.  Basically I did exactly what Tom Patton said to do.  He seemed to know what he was talking about and this was my first DIY attempt.  So far so good, this thing sounds great!  I'm going to let it break in a bit and get used to it some, then I'll share my thoughts about it.  SO far its as good as I could have hoped!

Nate

[Brinkman]

Great!

The 2604 is also what Jim specs in the headphone amp portion of the Ripper, which is otherwise identical to the Bugle (excluding the DAC/ADC).