Pearl Two

The clip I saw did not sound like French - Kobaian? Typical dumb American view of the world I have.

From Wikipedia:
In a 1977 interview with Vander and long-time Magma vocalist Klaus Blasquiz, Blasquiz said that Kobaïan is a "phonetic language made by elements of the Slavonic and Germanic languages to be able to express some things musically. The language has of course a content, but not word by word."
 
As for the spot on importance question, look at this Toshiba chart. Its the transconductance VS drain current. As you see 5 to 5.6 is practically the same just above the 30 millisiemens mark. So your input stage gain is very close to the original (23mA/4JFETS=5.75mA each on average VS 5mA in original). The larger resistors promote better sharing also. Wayne knew that there is an optimal region at about 5-6mA for the type no matter if adding a bit of nVsqrtHz from the net Rs resistance (Value/4). Its a thermal trade off for each one's dissipation at IDSS and noise most probably. 8.5V or 9.4V VDS at about 0.1V VGS look linear alike. Gate leakage current should be very close too. In a nutshell you should be sorted as you are.

Just to improve my understanding of matters: my quads have around 27-27,5mA. Voltage drop across R21-R24 is within 1mV in a quad (67-68mV, 68-69mV). I have lowered R10 (4k7) to get Vc 6.1 Vb 5.9 and Ve 5.3V around Q3. So there is 5.3V on the drains of Q6-9. Is that in a range where the 2SK170 works less well? What could be the effects on the sound quality? Audible? If the higher mA means higher gain I would actually welcome that (unless of course it degrades sound quality)
 
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The curves are steeper there. Bit less linear.

P.S. There was some technical and subjective mix test maybe from a German site that was recommending them at >6.5V but I can't find it now. You better listen on your own with higher source resistors and decide.
 
Official Court Jester
Joined 2003
Paid Member
The clip I saw did not sound like French - Kobaian? Typical dumb American view of the world I have.

From Wikipedia:
In a 1977 interview with Vander and long-time Magma vocalist Klaus Blasquiz, Blasquiz said that Kobaïan is a "phonetic language made by elements of the Slavonic and Germanic languages to be able to express some things musically. The language has of course a content, but not word by word."

they're , in fact , World's Citizens , in best meaning of the word

at least to my ( limited ) knowledge , they are having exactly right amount of French wakoosness :rofl: , and rest is ...... simply put - I adore their music
 
Rosewood Pearl with hand built case .... still need to put the Power switch in ... :)
 

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Very nice Rich. Love the rosewood. I may do something similar for my ACA in my office.

I hooked up and wired my Pearl 2 boards in the chassis today and I had distortion in one of the channels. Checking the voltages, I could not keep P1 adjusted to keep R16/R17 near 0, it would drift all over the place. I checked the voltage on R15 jumper and it seemed to be very stable, moved linearly with any adjustment in P1. That seemed to point to Q2 or Q11. Based on the experience of others, I replaced Q3 (ZVP3310) and it got rid of the distortion and I was able to keep the voltage stable around 0 at R16/R17. I will keep listening, checking for awhile. Hopefully I am really good now!

Waiting for a spool of microphone wire which has been back ordered from Parts Express. Once it arrives, I can finish the umbilical and move it to my main system. Current shop system - 10 year old Yamaha HT Receiver, 30 year Yamaha TT with $25 AT cartridge and $50 AR bookshelf speakers does not do it justice. Sounds very good though, plenty of of gain.
 
I have been listening for 2 days and everything sounds real good. The only issue is I cannot keep voltage adjusted at junction of R16/R17 on one channel. The same channel had a lot of distortion until I replaced Q2 (ZVP3310). It got rid of the distortion but not the voltage oscilliation. It can swing +/- 1.5 v where the other channel is +/- 75 mv, fairly stable. Any ideas on what could be causing or how to troubelshoot? All other measurements are in line with Wayne's and voltages are very stable everywhere else on the circuit except at R16/R17 and to the output.

Replace Q11?
What about C9? Is that in place to smooth out oscilliations in that part of the circuit? Could that be bad?

Any pointers are appreciated.

Thanks
 
I have been listening for 2 days and everything sounds real good. The only issue is I cannot keep voltage adjusted at junction of R16/R17 on one channel. The same channel had a lot of distortion until I replaced Q2 (ZVP3310). It got rid of the distortion but not the voltage oscilliation. It can swing +/- 1.5 v where the other channel is +/- 75 mv, fairly stable. Any ideas on what could be causing or how to troubelshoot? All other measurements are in line with Wayne's and voltages are very stable everywhere else on the circuit except at R16/R17 and to the output.

Replace Q11?
What about C9? Is that in place to smooth out oscilliations in that part of the circuit? Could that be bad?

Any pointers are appreciated.

Thanks

Any of the experts have any advice?:D
 
I don't know how relevant is this - I see people building phono stages with resistors away from PCB surface as if they are expecting heat from them like power amp resistors. IMO keeping small component lead in phono stage and components near to PCB surface should keep some of these problems away. Resistances placed near to PCB, leads bent in curve shape and transistors legs kept possible away from each still allowing closet mounting onto PCB.