|Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.|
Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
||Thread Tools||Search this Thread|
|19th May 2018, 05:29 PM||#31|
Join Date: Oct 2003
Finally, the balanced version
Have been planning to build this for a few years now, and finally finishing this week.
Always want to build the balanced version only in order to get round the problem with low PSRR at the top rail.
Changes to the circuit are as follows :
+/-20V rails (battery powered, followered by 3x LM329, LP filtered to drive 5x BC327/337 follower in parallel)
Using 2SJ109 for 1st stage, 2SK389 for 2nd stage
2SJ109 is cascoded by 2x BC560C at -7V base voltage
R1,2,3,9,10 10k (Caddock MK132)
R5 2.5k nominal (2.7k S102//33k Beyschlag, fine trimmed for common mode DC)
Rv1 51R-51R//5k trimpot (for 1st stage differential DC)
R6,7 51R-51R//5k trimpot (for overall differential DC)
R4,C1 2.1k,147n (100n//47n)
R8,C2 880R,3.88n (887R//110k,2.2n//1n//680p)
After trimming, DC at the output before rumble filter is stable to within +/-5mV.
It is surprising stable considering the DC gain of 60dB.
A 10Hz rumble filter (15n/1M) was also added before the output followers, which are 2SK2145GR at 4mA.
The rumble filter will take care of any remaining DC after R9,10.
Gain at 1kHz is measured at 620x, which is as per expectation.
Still some final wiring to do.
Thanks for the nice and simple circuit.
|19th May 2018, 07:32 PM||#32|
Join Date: Aug 2002
Wow, only 13 years later
I like your 3-D-thinking!
Do you have a schematic?
"I can feel what's going on inside a piece of electronic equipment. I have a sense that I know what's going on inside the transistors." Robert Moog
|Thread Tools||Search this Thread|
|Thread||Thread Starter||Forum||Replies||Last Post|
|JFET SRPP RIAA Preamp||wrenchone||Analogue Source||250||24th July 2015 08:32 PM|
|Open loop bandwidth in op-amp.||beppe61||Solid State||94||1st October 2007 04:56 AM|
|BUF04 Open Loop||Bonsai||Solid State||0||7th August 2006 10:09 AM|
|Riaa Pacific Jfet||maxpou||Analogue Source||23||15th April 2006 05:51 PM|
|Op-amp open loop bandwidth.||beppe61||Solid State||18||18th February 2005 02:30 PM|
|New To Site?||Need Help?|