the middle one is FH9, the bottom one is PS module and the top one input select/dsp. i like this amp, as you said very muscular signature, gonna use it to run the woofers and alpha 20 to run the mid/high after i finish new speaker project. and yes it is a wooden box, i used one single big heat sink for two fh9 boards, i ran it for a few hours and it does get pretty warm but not much to worry about, it has ventilation on bottom and top.
the FH9 had some noise when connected to my media PC and i couldn't get rid of it no matter what, i know my SMPS power supply is clean since the amp is dead quiet connected to any other sources but funny thing all audible noise went away when i use PCA as a pre between pc and the amp, and even better it adds its sweet character to music
and also the PCA is powered with a laptop power supply !
the FH9 had some noise when connected to my media PC and i couldn't get rid of it no matter what, i know my SMPS power supply is clean since the amp is dead quiet connected to any other sources but funny thing all audible noise went away when i use PCA as a pre between pc and the amp, and even better it adds its sweet character to music
and also the PCA is powered with a laptop power supply !Attachments
Wow, that PSU box reminds me of how my P2P power supplies all look. Nice work - that's a lot of power supply in that box. What 3 different amps?
I just managed to make a DC-step-up, a cap Mx, and a CRCRC with 10mF caps all fit on a 6cm x 8cm vero board. This one is clean - like batteries clean (no mains peaks FFT) when powered with 12v 2A smps wallwart.
I just managed to make a DC-step-up, a cap Mx, and a CRCRC with 10mF caps all fit on a 6cm x 8cm vero board. This one is clean - like batteries clean (no mains peaks FFT) when powered with 12v 2A smps wallwart.
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that looks good , very compact and neat, mine looks like Frankenstein, for now i only run my fh9 with that but it will also run alpha 20 in future (smps for fh9 and trafo for alpha ) if i manage to feed the alpha with smps i will remove the trafo, the other smps is 12v for speaker protection , fans and stuff just because i wanted to keep it separate from main supply instead of using regulator.
Here are the pix of my desktop build. The power supply is this The σ25 positive regulated power supply and gets its input from an 18VAC/1A wall wart.
It outputs just under 18V.
The capacitor bank uses six Nichi UPW's, 470uF/50V and five Wima 1uF from my stash.
I use the amp to drive a pair of Massdrop/Fostex TH-X00 'phones rated at 25 ohms.
The in/out jack are these SJ5-43502PM CUI Inc. | Connectors, Interconnects | DigiKey and are the best I've found. I used them instead
of the stock board mounted jacks to give it a bit more space.
Enclosure is this: https://www.hammfg.com/files/parts/pdf/1455K1201BU.pdf
It outputs just under 18V.
The capacitor bank uses six Nichi UPW's, 470uF/50V and five Wima 1uF from my stash.
I use the amp to drive a pair of Massdrop/Fostex TH-X00 'phones rated at 25 ohms.
The in/out jack are these SJ5-43502PM CUI Inc. | Connectors, Interconnects | DigiKey and are the best I've found. I used them instead
of the stock board mounted jacks to give it a bit more space.
Enclosure is this: https://www.hammfg.com/files/parts/pdf/1455K1201BU.pdf
Ideally there are caps right on the copper plane for drain of the MOSFET for a low impedance path for current to dispense through the MOSFET. Since Funch is using such big output caps he went instead with thick wire to an offboard cap bank. In this case it is serving as a charge reservoir to improve bass dynamics and reduce stereo cross talk from rail modulation. Placing it before regulator would put impedance bottleneck on regulator. From normal CRC filtering of DC from a bridge you want that before regulator. But it is different purpose here.
Note that higher R4, will increase bias current along with having a higher H3 relative to H2 but overall THD will go down. It may sound more "resolving" and powerful, but might be more fatiguing to some ears.
68ohms is a high value - 51ohms to 57ohms is a good tradeoff, but it is personal and adjust to taste.
What is your opinion of dual 1000uF Silmics on the outputs vs dual 1000uF OSCONs?
68ohms is a high value - 51ohms to 57ohms is a good tradeoff, but it is personal and adjust to taste.
What is your opinion of dual 1000uF Silmics on the outputs vs dual 1000uF OSCONs?
Glad you thought of adding provisions for a switch. I want to try one of these stepped attenuators for my desktop build. Cheap and highly recommended in another thread by DestroyerOS. Might be hyperbole, but he said:
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Since you all are talking caps, I'll mention that I recently made a thread for sharing all of my cap rolling experiences so far with this amp. Yesterday I got a pretty fascinating response...member Mark Johnson asserted in Post #40 that the optimal coupling cap value for a headphone amp is no less than 10,000uF! Apparently this is based on Douglas Self's work.
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