Here are some quick measurements using my older (noisier laptop), and a smaller CRCRC (2200uF caps) but shows excellent performance as a headphone amp driving 1.0vpp into a 50ohm load. THD is about 0.0056% mostly H2. This is with the through hole prototype board using 2SA1837 under 90mA bias and 24v Vcc.
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@jacques antoine
You´ve to buy the part list recommended parts for 1U integration (principally capacitors; boardspacer 5mm, PCB thickness 1.6mm).
I´ve checked with this model (DXF HIFI2000 available): Galaxy GX243 230 x 230 x 40 mm pannello frontale 10mm ARGENTO
JP
You´ve to buy the part list recommended parts for 1U integration (principally capacitors; boardspacer 5mm, PCB thickness 1.6mm).
I´ve checked with this model (DXF HIFI2000 available): Galaxy GX243 230 x 230 x 40 mm pannello frontale 10mm ARGENTO
JP
Thanks, JP. New Gerber with low cost RK09 pot has been uploaded. That other $41 pot would have cost as much as all other parts of the amp combined, if not more!
JP,
The cost of the part: 12HP059-RED is $10ea x 5 is high. Are those the RCA PCB jacks? Is there a lower cost option?
So, I take it people either aren't familiar with Salas' SSLV or they aren't interested in using it as a PSU? There's a GB for boards that is going to close soon.
https://www.google.com/url?sa=t&rct...php?id=99719&usg=AOvVaw1ONRslEOYVk-u1gb9NAumR
https://www.google.com/url?sa=t&rct...php?id=99719&usg=AOvVaw1ONRslEOYVk-u1gb9NAumR
It is my experience that a shunt regulated linear psu using a mains transformer can not be as low noise/ripple as using a smps and DC step up regulator followed by cap multiplier. You will still have residual peaks at 60Hz,120Hz,180Hz with a shunt regulator. It is very difficult to filter out 60Hz noise. What a DC step up does is to convert the AC “mains” frequency from 60Hz (50Hz) to about 400kHz-1MHz, where it is much easier to filter completely with much smaller capacitors and steeper filter slopes.
Look at the FFT on this preamp, there’s no mains bumps or harmonics to be seen.
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I just received the white metal PCB DC boost unit in the mail today. It looks very well made and measures clean - same as previous boost unit but much more compact and capable of putting out 50v. With the cap multiplier in place, the max Vcc is about 47v. If you have no need to drive very high output levels, setting the preamp Vcc at 40v seems to have less THD than at max 47v.
Here is 40v Vcc into the preamp driving 20vpp into 7kohm as before:
Here is the one I am testing now. The equivalents from Ali or eBay are the same I am sure at about $6ea.
Amazon.com: GEREE 250W Boost Converter DC/DC 8.5-48V to 12-50V Output Step-up Module Mobile Power Supply Max 10A: Home Audio & Theater
They are rated at 10amps and have high quality 14 ga wire presoldered to them. The aluminum board is convenient to bolt directly to a case for heatsinking if operating at high currents. It would seem that two of these in series with two 19v SMPS would make a fine (zero hum), extremely compact, dual rail supply for many Class A or AB amps out there for a low cost. The switching frequency is reported to be 170kHz, well above audio band. With the cap Mx and CRCRC, you can see that the supplies are absolutely silent.
Here is 40v Vcc into the preamp driving 20vpp into 7kohm as before:
Here is the one I am testing now. The equivalents from Ali or eBay are the same I am sure at about $6ea.
Amazon.com: GEREE 250W Boost Converter DC/DC 8.5-48V to 12-50V Output Step-up Module Mobile Power Supply Max 10A: Home Audio & Theater
They are rated at 10amps and have high quality 14 ga wire presoldered to them. The aluminum board is convenient to bolt directly to a case for heatsinking if operating at high currents. It would seem that two of these in series with two 19v SMPS would make a fine (zero hum), extremely compact, dual rail supply for many Class A or AB amps out there for a low cost. The switching frequency is reported to be 170kHz, well above audio band. With the cap Mx and CRCRC, you can see that the supplies are absolutely silent.
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You only need one external SMPS and it can be anywhere from 12v to 24v as long as relatively clean. A major OEM brand like HP/Dell/Sony/Lenovo etc SMPS should be good. Do not use a no-name brand $5 to $7 19v SMPS as they are typically noisy. I personally use an HP 19v 4.6amp one about $15 new on eBay. I have also had good luck with a 1amp 12v SMPS Vonage brand wall wart used on the Lepai 2020 amp. There is also a 24v 5amp smps brick on Amazon for $17 that works well.
Here is the one I use and I can confirm it is very quiet.
🔥GENUINE HP PA-1900-32HT PN 608428-001 AC POWER ADAPTER CHARGER 90W 19V🔥 | eBay
Here is the one I use and I can confirm it is very quiet.
🔥GENUINE HP PA-1900-32HT PN 608428-001 AC POWER ADAPTER CHARGER 90W 19V🔥 | eBay