-VSR is no slouch.
Thank you for you fast respons, Salas. Im not sure what you mean by no slouch? You mean its not an option? Or that the VSR is quiet a fine alternative to a Z201?
Ive got two 2x18v 2.2A transformers for the powersupply, so i will go with the 63v then. I'll have a look later on if im going with the mundorf or the kemet.
Last edited:
I mean they are a competent and effective alternative.
You will need high enough value RD/Link resistors in the raw psu board to tame the 2x18vac in series i.e 36vac result. Maybe 20Ω 2W. Mains tend to be high and >50V resultant raw dc under load is precarious for J1's max VDS rating in the SSLV1.3S input circuit.
You will need high enough value RD/Link resistors in the raw psu board to tame the 2x18vac in series i.e 36vac result. Maybe 20Ω 2W. Mains tend to be high and >50V resultant raw dc under load is precarious for J1's max VDS rating in the SSLV1.3S input circuit.
Will go with the VSR on the R1 and R17 for sure. And maybe i'll decide later on to put them in the Rx positions as well.
Yeah i figured that i needed to raise the RD value a bit. I was looking for 2x15v, but a colleague of me had these 2 amplimo 2x18v laying around which i could buy for a good price.
Btw, gone through most pages of this almost 1000 pages topic (mostly quick scrolls, with some more detailed reads when interesting). Amazing to see all the input and help in this topic. And very cool to see the ongoing development of the design and PCB's. Lovely forum, topic and compliments to the chief and everybody who made this design possible!
Yeah i figured that i needed to raise the RD value a bit. I was looking for 2x15v, but a colleague of me had these 2 amplimo 2x18v laying around which i could buy for a good price.
Btw, gone through most pages of this almost 1000 pages topic (mostly quick scrolls, with some more detailed reads when interesting). Amazing to see all the input and help in this topic. And very cool to see the ongoing development of the design and PCB's. Lovely forum, topic and compliments to the chief and everybody who made this design possible!
I'm in the final assembly stage for the older version of the Simplistic RIAA phono pre. Where is an appropriate place for connecting the chassis grounding lug for turntable connection?
Edit: I see a via labeled GND on each board...am I running a wire from each board to the grounding lug?
Edit: I see a via labeled GND on each board...am I running a wire from each board to the grounding lug?
Last edited:
As a matter of curiosity, I wonder how difficult it would be to assemble this board without the RIAA compensation circuit, giving us a simple flat gain stage? I plan on building one in this next group buy, and would somewhat prefer to do RIAA equalization post-ADC if it were easy to accomplish.
If you will skip everything between R4 and C3 with a jumper link it will become flat. Since records are inverse RIAA equalized there is overload danger after that. Clipping peaks. It could be contained to a degree by setting lower gain than normal for your cart.
Thanks, Salas. I'm aware of the different gain requirements given a non-RIAA-correcting circuit and have had good success with it in the past with microphone preamps. I'll give it a try and report back!
Help! I’m so confused. I have hum.
I built a Ultra FSP a while back. It’s been great and dead quiet.
Last night I finished building some RCA cables and swapped those into my TT and Ufsp….. and suddenly I got a hum.
I tried putting the old cables back in and no matter what I use I have a hum.
There was no hum and everything was dead quiet prior to this cable swap.
When I touch the phono stage chassis and the barrel of any of the rca jacks the hum goes away.
Also is the grounding post for the TT supposed to make contact with the chassis? Mine is insulated from the chassis.
I built a Ultra FSP a while back. It’s been great and dead quiet.
Last night I finished building some RCA cables and swapped those into my TT and Ufsp….. and suddenly I got a hum.
I tried putting the old cables back in and no matter what I use I have a hum.
There was no hum and everything was dead quiet prior to this cable swap.
When I touch the phono stage chassis and the barrel of any of the rca jacks the hum goes away.
Also is the grounding post for the TT supposed to make contact with the chassis? Mine is insulated from the chassis.
Is there only hum or some music and hum? If its only hum, output stage FETs could have been harmed if it was a hot cable swap. Yes the TT ground lug is better to be in contact with the chassis.
There is music too. The grounding post I used apparently is insulated by design, so I made my own connection to chassis. It’s better… but there is still noise that wasn’t there before
Check with the DMM's continuity buzzer that all chassis panels are in good contact. Let us know drain pin to ground DC measurements for Q5 and Q6.
Just a long shot, but...check your RCA sockets. Maybe they need some tightening on the enclosure after changing cables. I had such an issue in the past with loose RCA sockets. Got them tight again, hum gone.
That's not right. Unless you measured source pins. K170 is DGS as we face it.
Better pull the Q5s and verify them with a component tester or other methods.
Better pull the Q5s and verify them with a component tester or other methods.
This time the drain to ground bias voltages look alright. About the same for the channels as well as evenly spread between top and bottom JFETs. They never are exactly halved between drains because of tolerances. Still good enough. Conclusion is your output buffer stage JFETs are alive.
That's a valid suggestion. Extending to check the continuity resistance and mechanical fitness of all cables. In case of a bad indication some solder joint could have turned bad or a connector screw became loose.Just a long shot, but...check your RCA sockets. Maybe they need some tightening on the enclosure after changing cables. I had such an issue in the past with loose RCA sockets. Got them tight again, hum gone.
- Home
- Source & Line
- Analogue Source
- Simplistic NJFET RIAA