Hello apex audio,
You have, also, a project (pcb, layout, etc. ..) of a preamplifier to combine with HV23?
thanks
You have, also, a project (pcb, layout, etc. ..) of a preamplifier to combine with HV23?
thanks
Hello,
took me four 22000uF 100V capacitors and two 500VA toroidal ... really great amplifier ....
😱😱
Apexaudio, in your opinion which preamp is better to combine with this amplifier?
took me four 22000uF 100V capacitors and two 500VA toroidal ... really great amplifier ....
😱😱
Apexaudio, in your opinion which preamp is better to combine with this amplifier?
Hello to you all,
you know a good preamp to combine with HV23? also be build with a kit.
thanks
you know a good preamp to combine with HV23? also be build with a kit.
thanks
If you need only a buffer without gain, a two transistor CFP will sound very good. Just need to ensure that it's compensated for HF stability.
Yes, I am currently using one with my chip power amp. I think it sounds very good. I'm currently out of town and will post the circuit I use when I return ( on the 24th). It is dc coupled but has a cap between the output and the power amp input. So some offset ( from the source) at the input doesn't affect it.
I used a separate supply while testing. The board is supposed to tap the +/- 36 V from the power amp. I had a hum problem with a tube stage doing that and switched to a separate supply. Didn't check the ss buffer with the power amp supplies. I've attached the circuit with supply.
Attachments
DAC output goes to top of Volume control.
Slider goes to Buffer input.
Pot is a dual 50 K Alps pot . You can use 10 K or 22K also. It just loads the DAC stage. As low as 10 K should be OK for a DAC. I generally prefer as high as possible. Only price you pay is poorer s/n ratio due to the higher pot resistance. If this isn't audible I don't worry about it.
Connection cables are short and so HF loss due to capacitance is very low.I get a worst case loss of about 0.4dB at 20 Khz with a total of 2 meters of cable. My cable is less than 110pF per meter though I used 150 pF to simulate the response.
Note that the higher the pot value the lower the HF roll of frequency. If you can hear a 0.5 db roll off at 20 Khz then you better use a 22K or lower pot !
Slider goes to Buffer input.
Pot is a dual 50 K Alps pot . You can use 10 K or 22K also. It just loads the DAC stage. As low as 10 K should be OK for a DAC. I generally prefer as high as possible. Only price you pay is poorer s/n ratio due to the higher pot resistance. If this isn't audible I don't worry about it.
Connection cables are short and so HF loss due to capacitance is very low.I get a worst case loss of about 0.4dB at 20 Khz with a total of 2 meters of cable. My cable is less than 110pF per meter though I used 150 pF to simulate the response.
Note that the higher the pot value the lower the HF roll of frequency. If you can hear a 0.5 db roll off at 20 Khz then you better use a 22K or lower pot !
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Hello to all,
I have a small problem, I replaced the toroidal transformers, with these 55189-P1S2 TALEMA - Trasformatore: toroidale | TME - Componenti elettronici , I now have different voltage, I measure over near the entrance + 100v and 50v input -. I noticed that after a few seconds the LED on the PCB will illuminate. Can anyone help me understand what happened .....
I have a small problem, I replaced the toroidal transformers, with these 55189-P1S2 TALEMA - Trasformatore: toroidale | TME - Componenti elettronici , I now have different voltage, I measure over near the entrance + 100v and 50v input -. I noticed that after a few seconds the LED on the PCB will illuminate. Can anyone help me understand what happened .....
