rdpx
Senior Member

Can you check 8R2 resistor voltage drop ,

Idss is the current which flows in the drain-source channel when Vgs= zero ,you need to match transistors so they draw 6mA when Vgs=0V, you won't...

Exactly same problem as I have with one of the calvins but I couldn't go any lower than 30mV to achieve 0V I had to increase the range of the pot by...

That's correct , please disregard decoupling mains ground bit

DDCR is the way of decoupling mains ground from star/chassis with network diode-diode-cap-resistor ,

Bump Sent from my D5803 using Tapatalk

Guys , how you've sorted grounding arrangement , I think something like mains earth to the case star ground , from there to paradise board ground...

Seems like I kind of sorted both Calvins , it took bit of tweaking of R5 R6 R7 R11 , now I run one set with all resistors @2R2 and the other one with...

I think it's exactly the same thing , gate threshold volatge

and one more thing , on the main reg board replaced J310 with J113 and resistors 3k3 with 1k , they seem to have same pinout but I remember swapping...

Just to make sure all buffer parts are as follow: Q3,Q6 MJE350 PNP power transistor Q1,Q4 PF5102 n-JFET, IDSS=6mA, VTH = -1V Q2,Q5 J107 n-JFET,...

Simon What values of C1&C2 you use , Calvin manual says MJE/MJD 350 ( C1,C2 = 100-47pF)

It would be great , can you order 8 so there is something to choose from and if you don't mind 8 of J107's , I'd like to start fresh ( ordered...

Simon where did you get those MJE350 bipolars , for some reason I can't get 2SA1381 to work , what's the best way to match them? Same applies to...

I like the idea of trimpots , how do you match bipolars and jfets , DCA55 is not much of a help , any quick to build circuit ?

What's optimum current should be running through Calvin power transistors , I have 19mA only , shouldn't be close to 30mA?

Powered up one channel , I have fairly big voltage fluctuation +/- 80mV on the output ( with 10k on input) and 1.6V on pin 6 of the OPA . I covered...

Charity shop score plays perfect hello 1982 Sent from my D5803 using Tapatalk

Did you consider a Croft? Sent from my D5803 using Tapatalk

Did you check the fuses? Sent from my D5803 using Tapatalk

Very kind of you , thank you Simon

http://www.silverfast.com/highlights/kodachrome/en.html This scanning software is good. You might want to do a bit of research before committing...

Simon , don't worry about 8R2 resistors I have some 3W in the cupboard, appreciate your help with inductors

Kodachrome can be a difficult to scan. Have a look here: http://www.filmscanner.info/en/Kodachrome.html Sent from my D5803 using Tapatalk

Thanks Sandro , I must find Calvins simulations , is there a particular reason to use 2KSA170 ?

I meant 10ohm 3w resistor on Paradise board which need to be dropped in value to provide enough current for RIAA and Calvin, I think it should be 8.2...

I think Calvin on Diy thread mentioned something and came up with some simulations for same values of R5 R6 R7 &R11 but cannot find it now , I try to...

Simon , couple more questions , in the Calvins do you use same value R5 R6 R7 R11 (6R8 or 4R7) or as per schematic Did you change R104 R204 from 10R...

"Anyone wanting it"... That would be me! :) Let me know if you get anywhere with this. R Sent from my D5803 using Tapatalk