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 to lower value due to increased current draw
Location: Shenfield
Posts: 574
I'm Slav.
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 to lower value due to increased current draw
Location: Liverpool
Posts: 766
I'm Sandro.
WP_20170927_12_35_55_Pro.jpg
I have completed the boards
all BC 337 and BC327 are matched between the 2 channels and the groups whit Hfe from 397 to 404
EG the left and right channels have all 16 transistors matched at Hfe 401
I have a question in regards to the Calvin buffers just to make sure
Q1 =2SK170 8.2 mA
Q2 =PF4391
Q3=2SA1930
C1 = C2 =220 Pf
I have used those as they are what I have at present but I can wait and get others
What are the best ?
And quote from guide :
For the input transistors, also these can be used: 2SK170 (IDSS=8...8.5mA) / cascode: PN4391
BF244B / cascode: BF245C (C1,C2 = 22pF)
For the output transistors, a lot of choice is possible: BD 140 (Suffix -16) ( C1,C2 = 180-220pF)
MJE/MJD 350 ( C1,C2 = 100-47pF)
2SB 649/A (Suffix C oder D)
2SA 1930 ( C1,C2 = 180-220pF)
MJE 253 ( C1,C2 = 47-22pF)
Should C1 C2 be chosen for the input transistors as stated for the BF244 /BF245 = 22Pf
or should it be chosen for the output transistors ?
Location: Liverpool
Posts: 766
I'm Sandro.
Location: Shenfield
Posts: 574
I'm Slav.
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 work my way through one more time
What power resistor in the current sources do you use 8R2 ?
Location: Liverpool
Posts: 766
I'm Sandro.
Location: Shenfield
Posts: 574
I'm Slav.
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 ohm, am I right?
Location: Liverpool
Posts: 766
I'm Sandro.
Yes I have dropped that to 7.6 Homes and fitted same slightly larger heat sinks
Location: Shenfield
Posts: 574
I'm Slav.
Location: Liverpool
Posts: 766
I'm Sandro.
I use the values from the notes, not the schematic and have always built with j107 and 5102 or whatever the match is. I use mje350 and 220pf caps. On the shunt I run 8.2 ohm 5 watt non inductive wire wound five watts and heat output is modest if you use a 300mA choke regulated power supply/ pre regulator and stick to 25.5- 26v under load into the shunt.
Slav I think I have a spare quad of those 8.2 ohm resistors. Ill include them with your coils.
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