Hi massimo,
a link wouldn´t be helpful because you can´t find any schematics.
It´s just sold as full kit, so pcb and all parts.
Greetings Ulf
Hi,
I have built one channel of MM version of Salas RIAA, as described in PSGR's PDF (Salas-RIAA-PDF-v1). I built the circuit point-to-point using layout of RCruz.
I am powering the RIAA with Salas Shunt V1.2 built on breadboard. Shunt output is steady 25V.
The problem is that I do not have seem to have any amplification. The sound level through my speaker is much lower than it should be for 41dB gain of RIAA stage.
I have double checked all connections and resistor values, but I cannot find my error.
The voltage across the led string is 7.5V.
Voltages on Q6
S 25V
G 7.5V
D 7.5V
Voltages on Q3
E 16.2
B 7.5
C 7.0
Voltages on Q1
S 7.0
G 0
D 0.19
Voltages on Q2
S 7.8
G 0
D 0.17
Voltages on Q5
S 17.7
G 7.8
D 7.8
Any suggestions to help track down the problem would be greatly appreciated.
Thanks for your time and help.
Gary
I have built one channel of MM version of Salas RIAA, as described in PSGR's PDF (Salas-RIAA-PDF-v1). I built the circuit point-to-point using layout of RCruz.
I am powering the RIAA with Salas Shunt V1.2 built on breadboard. Shunt output is steady 25V.
The problem is that I do not have seem to have any amplification. The sound level through my speaker is much lower than it should be for 41dB gain of RIAA stage.
I have double checked all connections and resistor values, but I cannot find my error.
The voltage across the led string is 7.5V.
Voltages on Q6
S 25V
G 7.5V
D 7.5V
Voltages on Q3
E 16.2
B 7.5
C 7.0
Voltages on Q1
S 7.0
G 0
D 0.19
Voltages on Q2
S 7.8
G 0
D 0.17
Voltages on Q5
S 17.7
G 7.8
D 7.8
Any suggestions to help track down the problem would be greatly appreciated.
Thanks for your time and help.
Gary
Your measurements look well except Q5's current. Up your R7 to 1k2. I assume a typo and that you have 17.7V on D not on S. Orientation is S to R7. 2SK170s pins are DGS from left to right as you face their flat front, and all go D towards B+ side in this project.
P.S. Put your old R7 in series with R11, not the problem but will work better with new R7 1K2.
P.S. Put your old R7 in series with R11, not the problem but will work better with new R7 1K2.
Teflon RIAA caps
0.047uF 1000VDC Obbligatos teflon film & tin foil finished break-in, combined with PSU BG & all BG phono, it is the first time that I hear well the trumpets of Miles Davis and Louis Armstrong, now the sound is mas densely and round but without losing definition the voices are simply perfect now I can hear Ella Fitzgerald body without lose her characteristics sweetness & caress. I suppose now that will be very difficult to beat the Obbligatos due to his high voltage so sure has a very thick tin conductor & thick teflon film, for example V-Cap 0.047 teflon film & tin foil or copper foil are both rated only 600VDC Reliable capacitors 0.047uF teflon film & tin foil the same: max 600VDC, Aura teflon I suspect are metallized & also are 600VDC but I am waiting the news caps NOS teflon film & aluminium foil to compare but are rated only 200VDC.
0.047uF 1000VDC Obbligatos teflon film & tin foil finished break-in, combined with PSU BG & all BG phono, it is the first time that I hear well the trumpets of Miles Davis and Louis Armstrong, now the sound is mas densely and round but without losing definition the voices are simply perfect now I can hear Ella Fitzgerald body without lose her characteristics sweetness & caress. I suppose now that will be very difficult to beat the Obbligatos due to his high voltage so sure has a very thick tin conductor & thick teflon film, for example V-Cap 0.047 teflon film & tin foil or copper foil are both rated only 600VDC Reliable capacitors 0.047uF teflon film & tin foil the same: max 600VDC, Aura teflon I suspect are metallized & also are 600VDC but I am waiting the news caps NOS teflon film & aluminium foil to compare but are rated only 200VDC.
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Rcruz- search for the Lightspeed attenuator thread. In that thread, search for "LDR remote control" , author "Maximus".
I am going to use the Salas RIAA, but using the Salas symmetrical buffer at the end, instead of the source-follower. Then this would go into the LDR vol. control.
Salas, does that sound like a usable arrangement?
Cheers- Kent
I am going to use the Salas RIAA, but using the Salas symmetrical buffer at the end, instead of the source-follower. Then this would go into the LDR vol. control.
Salas, does that sound like a usable arrangement?
Cheers- Kent
I just actually incorporated an AC coupled B1 like in the output of my test LMC shown prepared recently in a few pages back, and it does very well fed to a Mezmerize between the KT88 triode amp. I think its good to avoid the integral buffer if you know you have a buffer next, but I would still use one if it will have a low input impedance LDR lower than 20k equivalent pot to drive. Don't forget to size your phono Cout according to what impedance it drives in your set.
Noise ??
Hello Salas, right now I finished mine Salas SJfet, and I love the sound of this
Everything looks ok except one thing, when I crank up the volume ( say 1/3 of volume) I get background noise (noise is the same even if I disconnect the turntable). Is not hum, this noise sounds like when we have the stylus on a track without anything recorded on that (like the end of the record). Right now I'm using a double shunt psu (only transformer rectifier and filtering are common).Any idea?
Hello Salas, right now I finished mine Salas SJfet, and I love the sound of this
Everything looks ok except one thing, when I crank up the volume ( say 1/3 of volume) I get background noise (noise is the same even if I disconnect the turntable). Is not hum, this noise sounds like when we have the stylus on a track without anything recorded on that (like the end of the record). Right now I'm using a double shunt psu (only transformer rectifier and filtering are common).Any idea?
Attachments
This one is very difficult to get it oscillating. Still take out that 0.1uF across B+ on the phono boards. Also give me the voltages you got on all drains and collector. Have you got an oscilloscope? Is this thing sounding like a grunge (low to medium frequency boiling like)? What is the gain of your preamp?