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- Mar 18, 2013
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- Fondler errrr... fan of all Nav's avatars
I have one of these coming and although they are considered great preamps, like all equipment, it can be made better
I was doing some surfing and came upon a mod that lowers the noise floor to ridiculous levels and also fixes some of the issues of the Sonic Holography circuit
"Replaced rail power supply electrolytic caps with long life 105ºC Nichicon 10,000 hour (HE) caps. Replaced all other power related capacitors on main board with long life 105ºC Nichicon (PW) caps.Replaced signal-path electrolytic capacitors with bipolar Nichicon (ES) Muse caps.
Replaced all 10% ceramic disk capacitors with 5% caps (polypropylene in the replaced op-amp’s feedback loops and Multi-Layer Ceramic Capacitors [MLCC rated C0G/NP0] in phono section differential amplifiers).
Replaced RC4136 op-amps in phono (IC6) and line sections (IC7) with paired OPA2134s mounted on Brown Dog adapters.
Adjusted amplifier gain so that merely 1V[SUB]rms[/SUB] input would no longer saturate (clip) the pre-amplifier line stage op-amp on 12V rails (changed gain from 8.561 to 5.662).
Changed Moving Magnet Phono 1 high loading capacitance to 270pF (from 390pF), allowing better match for modern moving magnet cartridges. Also replaced 180pF loading, all with MLCC caps.
Changed headphone output impedance to 120Ω to be in accordance with IEC61938.
Replaced pilot lamp with blue LED and its current limiting resistor with appropriate value.
Replaced a number of critical resistors with 1% metal film resistors"
How do these changes sound to you? It would seem the person who does this mod (BillD on the Carver Forum) is pretty well regarded so maybe this info could help others here. Seems stupid to already think about modding a preamp I have not auditioned yet but you guys have me so entranced with the magic you work so that I can't help myself LOL
If I read it right, these mods lower the noise floor to a crazy -114. I also found it interesting that the C1 and C9 have the same layout! Just a few things are more isolated
Discuss
I was doing some surfing and came upon a mod that lowers the noise floor to ridiculous levels and also fixes some of the issues of the Sonic Holography circuit
"Replaced rail power supply electrolytic caps with long life 105ºC Nichicon 10,000 hour (HE) caps. Replaced all other power related capacitors on main board with long life 105ºC Nichicon (PW) caps.Replaced signal-path electrolytic capacitors with bipolar Nichicon (ES) Muse caps.
Replaced all 10% ceramic disk capacitors with 5% caps (polypropylene in the replaced op-amp’s feedback loops and Multi-Layer Ceramic Capacitors [MLCC rated C0G/NP0] in phono section differential amplifiers).
Replaced RC4136 op-amps in phono (IC6) and line sections (IC7) with paired OPA2134s mounted on Brown Dog adapters.
Adjusted amplifier gain so that merely 1V[SUB]rms[/SUB] input would no longer saturate (clip) the pre-amplifier line stage op-amp on 12V rails (changed gain from 8.561 to 5.662).
Changed Moving Magnet Phono 1 high loading capacitance to 270pF (from 390pF), allowing better match for modern moving magnet cartridges. Also replaced 180pF loading, all with MLCC caps.
Changed headphone output impedance to 120Ω to be in accordance with IEC61938.
Replaced pilot lamp with blue LED and its current limiting resistor with appropriate value.
Replaced a number of critical resistors with 1% metal film resistors"
How do these changes sound to you? It would seem the person who does this mod (BillD on the Carver Forum) is pretty well regarded so maybe this info could help others here. Seems stupid to already think about modding a preamp I have not auditioned yet but you guys have me so entranced with the magic you work so that I can't help myself LOL
If I read it right, these mods lower the noise floor to a crazy -114. I also found it interesting that the C1 and C9 have the same layout! Just a few things are more isolated
Discuss
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