I used 2 resistor values to obtain 720k. Seems a hard to find value
Sent from my Nexus 5 using Tapatalk
Sent from my Nexus 5 using Tapatalk
Strange - I actually don't remember that part.
As R12 belongs to the RIAA it's value is critical. Using two precision resistors to form 720k is certainly the best option.
As R12 belongs to the RIAA it's value is critical. Using two precision resistors to form 720k is certainly the best option.
for the RIAA:
I can't get LCR 1200pf in USA. Can I use Mica or film caps, 1%
CD15FA122FO3F Cornell Dubilier - CDE | Mouser
or
BFC241911202 Vishay / BC Components | Mouser
I can't get LCR 1200pf in USA. Can I use Mica or film caps, 1%
CD15FA122FO3F Cornell Dubilier - CDE | Mouser
or
BFC241911202 Vishay / BC Components | Mouser
Two part number requests for Mouser or Farnell:
1. heatsink for QP (power supply FET)
2."thingy" that lets you easily swap in/out the Q1, Q2, Q3 transistors. Basically a female plug with three contacts.
thanks!
1. heatsink for QP (power supply FET)
2."thingy" that lets you easily swap in/out the Q1, Q2, Q3 transistors. Basically a female plug with three contacts.
thanks!
1: 588-WA-T220-101E or 567-262-75AB-01E is not critical if your keep input between 48-50v
2. For transistors i used this kind of thing but in the end i will solder transistors. 575-80143036
PS. Mouser codes
2. For transistors i used this kind of thing but in the end i will solder transistors. 575-80143036
PS. Mouser codes
Attachments
Yesterday i was playing with High Octane preamp and with another diy preamp but OPAMP based (Rod Elliot P06). After listening some songs with opamp preamp i moved to High Octane and observed the trebles are faded out and started playing with loading resistors. In P06 i use standard 47k loading resistors the same in high octane but it seems high octane have a different behaviour regarding loading. Can someone explain to me why is that ?
I use a MM Nagaoka MP110.
I use a MM Nagaoka MP110.
I did not installed the 100k input resistors.
From post #96 i should understand that with 100k installed i have a 47k input impedance ?
From post #96 i should understand that with 100k installed i have a 47k input impedance ?
If sound difference persists you can consider first some difference in RIAA actual curves (eg. tolerances) between projects.
Meantime i have installed the 100k input resistor and sound is more balanced. I would really love to have the fullbodied bass from the P06 opamp phono preamp on high octane, as details and openess is nice on high octane but bass a bit shy and dry
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My take on the High Octane
Finally found some time to take some Snaps (had to listen before 😀).
I used KSA1845, tried also BC550 but measured slightly higher noise (though still very low) and so the 1845 went in again. RIAA caps and resistors have been selected out of a dozen and final deviation is <0.5dB with channel mismatch smaller than 0.1dB.
PSU is a small DIY plug housing unregulated linear supply ~50V DC.
I like the sound, its very detailed and punchy 🙂 Very nice Project, thanks a lot to Hannes
kind regards, Daniel
Finally found some time to take some Snaps (had to listen before 😀).
I used KSA1845, tried also BC550 but measured slightly higher noise (though still very low) and so the 1845 went in again. RIAA caps and resistors have been selected out of a dozen and final deviation is <0.5dB with channel mismatch smaller than 0.1dB.
PSU is a small DIY plug housing unregulated linear supply ~50V DC.
I like the sound, its very detailed and punchy 🙂 Very nice Project, thanks a lot to Hannes
kind regards, Daniel
