What's optimum current should be running through Calvin power transistors , I have 19mA only , shouldn't be close to 30mA?
Location: Shenfield
Posts: 573
I'm Slav.
What's optimum current should be running through Calvin power transistors , I have 19mA only , shouldn't be close to 30mA?
Location: Liverpool
Posts: 766
I'm Sandro.
Not sure there is no information on the guide best I can say is If you can have a look at the Paradise Builders tread on Diyaudio post 3053 (I can not and just have little info as I got banned for posing 5 or 6 X )
I am going to have a play whit the buffers tomorrow (messed one up whit same heavy welding)
I am thinking about putting a square wave from the scope trough passive inverse RIAA and paradise then have a look at the picture Will this work?
Location: Liverpool
Posts: 766
I'm Sandro.
On my build whit 2SK170 and PN4391 output transistors2SA1930
I have set r5 and r7 whit a pot in parallel to the 22Homesresistors
The current through the combination is given by
V across the resistor over the resistance I=V/R
I have the following r5=15R 483 mV 32.2 mA
R7=15R 497mV =33.12
Changing the resistors to 6.8Rgive me the following
R5=6.8 297 mV 43.6 mA r7=6.8 294 mV 43.2
Changing the setting on the offset pot R8 changes thecurrent through bot resistors
The V drop for R5 R7=6.8 R at 30 mA should be around 200 mV
I now I have 210 mv on R5 and 202 mV on R7
A small adjustment of R7 increase current on Q6 and reducethe current on Q3
I have now R5 =208.7 mV and R7 208.7 mV
Small tweak ¼ turn on R8 and now volts drops are 201 and 200mV
One thig I have not done so far is fit a trim pot on R2 andtry that
Obviously the gains and Ids of the transistors /Jfet has aplay in the results I got
Still much more should be said on the Calvin Build guide
Sandro the original Calvin buffer thread has more info in it.
Kuzma Stabi/S 12", (LP12-bastard) DC motor and optical tacho psu, Benz LP, Paradise (phonostage). MB-Pro, Brooklyn dac and psu, Bruno Putzeys balanced pre, mod86p dual mono amps, Yamaha NS1000m
Kuzma Stabi/S 12", (LP12-bastard) DC motor and optical tacho psu, Benz LP, Paradise (phonostage). MB-Pro, Brooklyn dac and psu, Bruno Putzeys balanced pre, mod86p dual mono amps, Yamaha NS1000m
Location: Shenfield
Posts: 573
I'm Slav.
Location: Shenfield
Posts: 573
I'm Slav.
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 J107 ?
You've mentioned on DIYAudio testing Calvins as standalone unit , do you power them from Paradise boards with disconnected In ,Out, Gnd , just shortened with 100k?
yeh, just short the input with 100k. I'll be doing a Mouser order tonight/tomorrow would you like me to add a quad of MJE350's for you?
Kuzma Stabi/S 12", (LP12-bastard) DC motor and optical tacho psu, Benz LP, Paradise (phonostage). MB-Pro, Brooklyn dac and psu, Bruno Putzeys balanced pre, mod86p dual mono amps, Yamaha NS1000m
Location: Shenfield
Posts: 573
I'm Slav.
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 matched Pf5102 earlier today) , PM me how much I owe you (I'll participate towards shipping charge if applies) .
How do you match these Simon?
Regards
Location: Shenfield
Posts: 573
I'm Slav.
Simon
What values of C1&C2 you use , Calvin manual says MJE/MJD 350 ( C1,C2 = 100-47pF)