You're quite welcome! Yes, that's the servo board I offer for these amps.
I've been using a Rat Shack 12.6V-0-12.6V 2A transformer.
If I were getting an Antek, I would get this one:
AS-1212 - 100VA 12V Transformer - AnTek Products Corp
Hope that helps.
Thank you ammel68 !
Do you sell the servo pcb and parts as a kit ? or do you have a BOM ?
Will order the transformer
Hi,
Could anybody point me to the schematic of the servo? Thanks.
Hey Ricren, the schematic of the dc servo is here (schematic, left down corner).
Source (rockgrotto proboards com): "JHL" headphone amp | Rock Grotto
Yesterday I built the servo. I use a OPA2134PA. In Europe, available for 2,89 Euro (Conrad Electronic SE).
Start // DC_Offset: +38 mV
after 10 sec. // DC_Offset:. +0,02 mV
after 30 sec. // DC_Offset: +0,45 mV
after 1 min. // DC_Offset: +0,7 mV
after 10 min. // DC_Offset: +1 mV
after 12 min. // DC_Offset: +1,1 mV
after 30 min. // DC_Offset: +1,09 mV
after 50 min. // DC_Offset: +1,5 mV
after 60 min. // DC_Offset: +1,1 mV
That looks good.
A sound test still follows.
Regards
Schiller72
An externally hosted image should be here but it was not working when we last tested it.
Start // DC_Offset: +38 mV
after 10 sec. // DC_Offset:. +0,02 mV
after 30 sec. // DC_Offset: +0,45 mV
after 1 min. // DC_Offset: +0,7 mV
after 10 min. // DC_Offset: +1 mV
after 12 min. // DC_Offset: +1,1 mV
after 30 min. // DC_Offset: +1,09 mV
after 50 min. // DC_Offset: +1,5 mV
after 60 min. // DC_Offset: +1,1 mV
That looks good.
A sound test still follows.
Regards
Schiller72
Main signal is 1 kHz. The 50Hz is -80 dB:Not sure what you are showing in 3rd pic. Is the test signal 50Hz or is the hum just terrible.
Intermodulation distortion test: Two signals: 50 Hz and 1 kHz:
Are the -80 dB intrusions terrible?The intrusion of mains and mains harmonics is terrible.
.if You have laptop with working battery power,use rmaa on pc as playback and on laptop as recording, You will get lot better results ,what interface is used for recording?
I haven't laptop. I used Emu0204 with battery power
- Home
- Amplifiers
- Headphone Systems
- JLH Headphone Amp