I saw your post now. Nick...
I have a matcher Jfet N channel from Elector nothing special... The selected quad shows me about 12ma each jfet...
I didn't prove the cause of the instability, but I think it may be related to the trace from R105 (R5 on the official schematic) running right on top of the gate lead of Q104 (J2). The circuit was very sensitive to putting a finger in that spot. I found a way to reroute the board to make it more symmetrical and to get that trace out of the way on the left side. Hopefully that was the cause, but either way I like this layout better.
Attachments
I own the HD 600 and I also had the HD 58X Jubilee over for a long listen. But the 6XX should be like the HD 650. They are variations on a theme with a different blend of strengths and weaknesses in each one, but you can't go wrong with any in that series of Sennheisers.
Attachments
Has to be utilized like an op-amp cell with + - inputs, meaning open access to its feedback return node. Following established balanced to SE op-amp arrangements as described in technical articles.
I don't know if it would react badly or not, never had a reason to try it like that. In such a case I would have kept the rearranged networks impedance as low as in its standard application at least.
I don't know if it would react badly or not, never had a reason to try it like that. In such a case I would have kept the rearranged networks impedance as low as in its standard application at least.
Testers usually recognize the gate pin only because most JFETs are largely symmetrical for source and drain. If it says NJFET and also shows Vgs, Idss, etc. means that the JFET in the uPA is working well. Else the tester would be baffled thinking its diodes or declaring no component, something generally weird as an answer.
By changing the AC Vin alone to higher the DC output does not change. You only make the pass transistors hotter for a given mA load. If you want more Vout you could make Rx Rj higher to add voltage drop or change them to Zeners. Any extra voltage will be added to the 17V from LEDs base. There is a DCVin limit for breaking J1 J2 if pushed beyond their 40V VDS max (VDS=VDCin-Vout in this case as they are sitting on Vref) and a limit for the installed bridge diodes PIV and the electrolytic capacitors ratings of course.
Saved by the lights
After three years of enjoyable listening with the DCG3 I recently feared that I had caused some serious damage, which resulted in distressing headphone noises. With limited troubleshooting skills, I feared the worst. While carrying the unit (sans cover) to my table in a dimly lit room I noticed that one of the led bars remained lit (from stored capacitance I presumed) and that its related MJE sink was cold relative to the others. I soon realized that while rearranging my audio components, I had inadvertently pressed down on the DCG3’s top cover, causing it to come in contact with the MJE sinks (and possibly other parts). A new BC550 and sink insulators made for a surprisingly quick fix, and I’m back in the saddle. Bottom line…those arrays are more than pretty lights
While I had the hood up I changed out the split bobbin transformers for quieter toroidal types, and rechecked offset. It’s now back in the center of my modest but enjoyable system. Thanks for a terrific bit-o-kit Salas, and for the work you do to make ‘the good stuff’ accessible to the rest of us.
Keith
After three years of enjoyable listening with the DCG3 I recently feared that I had caused some serious damage, which resulted in distressing headphone noises. With limited troubleshooting skills, I feared the worst. While carrying the unit (sans cover) to my table in a dimly lit room I noticed that one of the led bars remained lit (from stored capacitance I presumed) and that its related MJE sink was cold relative to the others. I soon realized that while rearranging my audio components, I had inadvertently pressed down on the DCG3’s top cover, causing it to come in contact with the MJE sinks (and possibly other parts). A new BC550 and sink insulators made for a surprisingly quick fix, and I’m back in the saddle. Bottom line…those arrays are more than pretty lights
While I had the hood up I changed out the split bobbin transformers for quieter toroidal types, and rechecked offset. It’s now back in the center of my modest but enjoyable system. Thanks for a terrific bit-o-kit Salas, and for the work you do to make ‘the good stuff’ accessible to the rest of us.
Keith
Attachments
Here to say, Χρόνια Πολλά, Salas.
Best festive wishes to you and all this wonderful community.
Despite being horrible 2020, this year has brought me great diy highlights. Many of them, if not all, thanks to your expertise.
Back on topic, my only regret with DCG3 is that I don't have two of them
Best festive wishes to you and all this wonderful community.
Despite being horrible 2020, this year has brought me great diy highlights. Many of them, if not all, thanks to your expertise.
Back on topic, my only regret with DCG3 is that I don't have two of them