The high octane phono preamp

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#181
h_a said:
As always, getting the RIAA caps as high precision, high quality types is difficult.

If someone needs all required RIAA caps as super-duper 1% precision Polystyrene types as I used originally (LCR FSCEX), I can offer a full set with all 6x RIAA caps (for stereo) for 20 Euros. Yes these do not come cheap!
Click to expand...

Just saw this, I would like a set, if board isnt mailed yet they can go together, otherwise, thats OK, I will just get 2 packages! How much to pay pal for the caps? I will PM as well. Oh, I see, 20 euros...on the way!

Russellc
 
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#186
h_a said:
As always, getting the RIAA caps as high precision, high quality types is difficult.

If someone needs all required RIAA caps as super-duper 1% precision Polystyrene types as I used originally (LCR FSCEX), I can offer a full set with all 6x RIAA caps (for stereo) for 20 Euros. Yes these do not come cheap!
Click to expand...

Hi!
please count me in for 6 pcs
thank you in advance!
 
#187
h_a said:
As always, getting the RIAA caps as high precision, high quality types is difficult.

If someone needs all required RIAA caps as super-duper 1% precision Polystyrene types as I used originally (LCR FSCEX), I can offer a full set with all 6x RIAA caps (for stereo) for 20 Euros. Yes these do not come cheap!
Click to expand...

Hello Hannes,
i installed in RIAA network some Wima FKP2 polypropylene caps as i already had in my parts box and now i'm not sure if i should replace them with polystyrenes.
Did you installed polystyrenes from first time or did you tested also with polypropylene ?

Regards,
Adrian
 
#193
If Jan D. says so, I guess a "wall wart" is really good enough 😉
But I do hate those things, so plan to instead make a good (and simple) linear PS, and put it in a matching case next to the High Octane.

All you need is a 10VA transformer with single 36V secondary, a rectifier and a capacitor or two, for a bit of filtering. Plus of course a fuse holder, an on/off switch and some wire etc, and a box to put it in. Can be build point-to-point, or on a prototype/perf board.

I will probably use a Talema 2x18V, and wire the outputs in series to give 36V. After rectifier and caps, it will give app. 50V DC.

If DC turns out a bit too high, you can scrub 1V by placing a R33 resistor in series on positive side in PS (assuming total power consumption of High Octane to be 30mA). I have used PSU Designer to make a schematic of the basic circuit.

Some might say it is overkill, but I say it's quality 😎
 

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#194
I use the same solution. It happened to have a 2x20v transformer and i installed a 220R (if i remember well) between the two filtering caps in order to lower a bit more the output voltage. As the req power is low enough the disipation on resistor is very low.
My next plan is to install a LM317 after this CRC filter to have a steady 48V on output.
I would avoid a SMPS wallmart adapter.
 
#200
I guess a "wall wart" is really good enough
Click to expand...

Oh, I actually really like wall warts.

The old ones have EI-cores with low capacitance between the windings which keeps high frequency line junk out.

In addition they're located far away from the phono circuit which prevents humm pickup.

The high octane comes with a strong regulator which eliminates any poor regulation that might come from the cheap wall wart. Just use an overkill unit with a 0.5-1A rating or so.
 
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