No test or hacking on the pcb is needed, and the math is straightforward. See post #12.
Your use of that calculator is not appropriate for this circuit topology.
Also, C2 in one place is not the same as C2 in a different place.
C2 just a label, not a function. Don't worry about it, just follow post #12.
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So did the recommended changes help?
They are for only the stated line stage and audio cable loading.
To recap:
R13 should be a wire jumper.
C4 should be 1000 pF 2% @ 250V or better, polystyrene or polypropylene.
Make certain that it will fit the pcb properly, with short leads.
Don't change anything else.
They are for only the stated line stage and audio cable loading.
To recap:
R13 should be a wire jumper.
C4 should be 1000 pF 2% @ 250V or better, polystyrene or polypropylene.
Make certain that it will fit the pcb properly, with short leads.
Don't change anything else.
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Hi, I am still not sure why the OP is experiencing these issues.
However, we have revisited the design and have come up with a better circuit, this one is using a MOSFET as an output buffer, as well the RIAA has been re designed and improved. The new model name will be Z-PH20.
Using a MOSFET as the output buffer will make this phono preamp compatible with a lot of different preamps, not just our Z series PAS upgrade kits.
I am still finalizing the pcb layout, once this is done, I will order in a new set.
I am happy to send the OP the revised designed PH20 as a kit free of charge, so please 'pm' me.
However, we have revisited the design and have come up with a better circuit, this one is using a MOSFET as an output buffer, as well the RIAA has been re designed and improved. The new model name will be Z-PH20.
Using a MOSFET as the output buffer will make this phono preamp compatible with a lot of different preamps, not just our Z series PAS upgrade kits.
I am still finalizing the pcb layout, once this is done, I will order in a new set.
I am happy to send the OP the revised designed PH20 as a kit free of charge, so please 'pm' me.
See post # 25 for a free upgrade kit. I would take him up on that, regardless.
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@erhardaudio - I will PM you for further details. I love the way the preamp section sounds and I cannot wait to get the phonostage working one way or another.
My Digikey order should arrive tomorrow, so I can give the suggested modification a try. Shipping seems to take longer when I keep checking the status ;-P
My Digikey order should arrive tomorrow, so I can give the suggested modification a try. Shipping seems to take longer when I keep checking the status ;-P
I am happy to report that the proposed changes in Post #12 were successful 
Thank you so much!
It is clear, so very quiet, and vivid. Good soundstage depth, almost seems to minimize the pops and noises from used records too. My reference is Salas' Ultra FSP solidstate phonestage, which is certainly a level up from this Next Gen Dynaco PAS unit, but this is still a very capable unit that definitely has a place in my collection.
In case anyone is interested or for context, I have a Marantz TT-15 w/ Clearaudio Virtuoso MM cart, the Erhard Audio Next Gen PAS phono and preamp, a Salas Ultra FSP phono, Firstwatt Burning Amp 3 pre and the Burning Amp 3 amp. I have a variety of custom made speakers, but currently am using the Energy Pro22 Reference Connoisseur speakers.
I can't wait to explore the next round of vinyl. Thanks again everyone for your help and support
Thank you so much!
It is clear, so very quiet, and vivid. Good soundstage depth, almost seems to minimize the pops and noises from used records too. My reference is Salas' Ultra FSP solidstate phonestage, which is certainly a level up from this Next Gen Dynaco PAS unit, but this is still a very capable unit that definitely has a place in my collection.
In case anyone is interested or for context, I have a Marantz TT-15 w/ Clearaudio Virtuoso MM cart, the Erhard Audio Next Gen PAS phono and preamp, a Salas Ultra FSP phono, Firstwatt Burning Amp 3 pre and the Burning Amp 3 amp. I have a variety of custom made speakers, but currently am using the Energy Pro22 Reference Connoisseur speakers.
I can't wait to explore the next round of vinyl. Thanks again everyone for your help and support
an update. The fully revised Z-PH20 has now been released. This is a completely revised circuit, updated and improved RIAA and a MOSFET output buffer.
Purchase and kit details can be found here, https://www.erhard-audio.com/Preamp_Kits.html, Kit #3
Purchase and kit details can be found here, https://www.erhard-audio.com/Preamp_Kits.html, Kit #3