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14 minutes ago, vivolo said:

Does anyone have any extra Blue Hawaii PSU boards that they would be willing to sell me? 

I prefer to build a BH PSU as it is cheaper than a GRHV, and I am trying to make this more of a "bugdet" amplifier build.

Did you want the Blue Hawaii Ultra mini?  I believe I have one set of Electorstatic CFA boards and a BH Ultra Mini PS board.

Edited by sbelyo
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Another electrostat CFA lives. This one born on the 4th of July? The PCB is congo5's layout. The amps is powered by my GRHV PSU with ~405VDC rails.  Many thanks to Kevin for another wonderfu

Finally cased my ES CFA amp.  Returned the bias resistors to 1M with the larger heatsinks. Running 20mA bias for the output sections.

if you don't mind a warm case, this seems to be enough  heat sink 3.5" x 9" + case bottom after one hour its 40 degrees rise from ambient 70/110

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On 8/26/2019 at 12:16 AM, mwl168 said:

Finally cased my ES CFA amp. 

Returned the bias resistors to 1M with the larger heatsinks. Running 20mA bias for the output section.

It was quite hot in this size with that current of my build. Is your amp running hot too?

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8 hours ago, joehpj said:

It was quite hot in this size with that current of my build. Is your amp running hot too?

Where I live, the ambient temperature at this time (end of August) is around 70 F, about 22 Celsius. The heatsink temperature of the amp gets to about 45C fully warmed-up.

When I first cased the amp, the ambient temperature was around 27 Celsius and the heatsink was ~ 48C not quite 50.

I can see the heatsink hit high 50's C in Taiwan where the ambient temperature can easily hit low to mid 30's C this time of the year.

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1. I use the digital volume on my DAC but you can easily add a volume control to the amp.

2. This chassis I use is quite small - dimension is 160mm x 70mm x 311mm. It's only for the amp circuits and you cannot fit the entire amp in it. There is a PSU in a separate chassis. As an example, you should be able to fit the entire amp including the PSU in a chassis like this

3. My rough estimate for parts alone would be about $700 US that also covers chassis, transformer, connectors, wires and a reasonable 4-gang volume pot. Like most things these days, labor is the biggest investment.  Cost can escalate quickly if you start getting into fancy chassis, volume pot and boutique parts (resistors, capacitors, wires, etc.).

Edited by mwl168
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Thanks! I would use this together with ADI-2 DAC which has quite configurable line out volume options, so I guess I could easily live without a volume knob as well. Now I will look if there is a thread about voluntary builders, for a fee of course. I also sent out a question to my facebook network if there are any electronics builders out there. I decided that optimally I would like to build one myself with somebody who knows what he is doing. Starting with this, completely solo, is probably not a good idea. ?

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  • 1 year later...
BH Mini PSU        
           
Resistor   Mouser P/N      
100R 2 660-MF1/2CCT52R1000F / 273-100-RC      
1.2K 2 660-MF1/2CC1211F / 273-1.2K-RC      
330K 2 594-5093NW330K0J 3W L=20.5mm  
430K 2 594-5093NW430K0J 3W L=20.5mm  
4.7M 1 594-VR37000004704JR5 HV    
           
1M 1 72-T93YB-1M Trimpot    
           
Semiconductor          
IXCP10M90S 2 747-IXCP10M90S   *  
FQPF8N80C 2 512-FQPF8N80C   *  
LM7815 1 512-LM7815CT / 863-MC7815ACTG    *  
LM7915 1 512-LM7915CT / 863-MC7915ACTG    *  
           
Zener          
24V 2 78-BZX85B24      
100V 2 625-Z4KE100A-E3/73 / 78-BZX85B100-TAP     100V*2+150V*1=350V
150V 4 625-Z4KE150A-E3     100V*1+150V*2=400V
1N4007 2 625-1N4007GP-E3/73      
           
Capacitor          
0.1uF/1KV 2 505-MKS4.1/1000/10 P=15mm   80-PHE426PB6100JR06
220uF/500V 4 598-80LX221M500K452 D=30mm * KX
    80-ALC10A331CF450      
470uF/35V 4   P=5mm/D=10mm   FC KW
           
Other          
GBU610 2 621-GBU610 / 625-GBU8M-E3/51    *  
3N254 1 625-3N254-E4 / 625-2KBP10M-E4    *  
Heatsink Large 2 532-530002B02500G H=63.5mm *  
Heatsink Small 2 532-581202B25G H=50.8mm *  
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Any non-obsolete replacement for the 3N254? Thanks! 

Adding to the above BOM:

image.png

Here the Mouser basket as well (which is missing the obsolete 3N254 bridge rectifier): 

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=9472151902

I would also exchange the 220uF/500V cap with a Nichicon LGN2H221MELB45 as it is rated up to 105°C and even cheaper. 

Edited by starcat
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