How high would I need to go?
I was thinking 22 volt rails would do. I also understand that the rails are limited to 17 volts due to the relay. Could I bypass the relay without cap coupling the preamp out?
Rush
Oh, great idea.
The OPA2604 have been discontinued it seems. Is there another substitute?
Rush
I don't know, search for 48V max JFET input op-amps. They usually refer to their PSU max with the sum rails voltage.
I'm going to try this first, I already soldered the relay in place.
I'll order the OPA2604 from eBay and see. Several USA sellers have them. That IC is in a socket, so easy to change.
Rush
49C won't pose any danger to the sinked transistors. The electrolytics around there are all 105C also. Does the lid have ventilation holes over the sinks? You would surely prefer 40-45C though. Feels better. Ok the transformers are over nominal voltage but is it on the high bias setting too?
On Q1 Q2 mirror BJTs yes, we did that often here. For J1 J2 uPA we didn't try sockets though. Its not a phono stage on the other hand, shouldn't be sensitive to socketing.
It could be handy if planning to listen with alternative LTP JFETs (J1 J2).
In any case and for any parts see to achieve oxide free and firm contact to female socket pins though. Shorter legs help the parts stay firmer.
For quality contact use a lens under good light and clean the parts pins. Because there will be no soldering for its flux to automatically clean them somehow. Almost all the candidate JFETS are NOS. Their pins should be oxidized enough already.
It could be handy if planning to listen with alternative LTP JFETs (J1 J2).
In any case and for any parts see to achieve oxide free and firm contact to female socket pins though. Shorter legs help the parts stay firmer.
For quality contact use a lens under good light and clean the parts pins. Because there will be no soldering for its flux to automatically clean them somehow. Almost all the candidate JFETS are NOS. Their pins should be oxidized enough already.
VA you mean not mA?
The extra Tx for the selector can save on chances of ground loop low level spikes when you don't monitor the result with FFT analysis so to tweak the cabling etc.
Due to better power source separation. You could achieve a fine result with a tap from DCSTB's raw DC to I-select DC in though. Especially useful when short on box space.
The extra Tx for the selector can save on chances of ground loop low level spikes when you don't monitor the result with FFT analysis so to tweak the cabling etc.
Due to better power source separation. You could achieve a fine result with a tap from DCSTB's raw DC to I-select DC in though. Especially useful when short on box space.