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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.

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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.

build it, put it in a super fancy box, and sell it for $37k betcha it sounds better than the high priced spread, at least no stupidly expensive and useless input transformers. its a push pul

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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.).

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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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On 10/9/2019 at 3:55 AM, vivolo said:

I have created a BOM for the Blue Hawaii ultramini Power supply. I still need to select the big caps and screw terminals.

Which PSU is this exactly? Can link to any schematics with details? Thanks

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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    
IXCP10M90S 2 747-IXCP10M90S   *  
FQPF8N80C 2 512-FQPF8N80C   *  
LM7815 1 512-LM7815CT / 863-MC7815ACTG    *  
LM7915 1 512-LM7915CT / 863-MC7915ACTG    *  
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      
0.1uF/1KV 2 505-MKS4.1/1000/10 P=15mm   80-PHE426PB6100JR06
220uF/500V 4 598-80LX221M500K452 D=30mm * KX
470uF/35V 4   P=5mm/D=10mm   FC KW
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:


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


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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How about 621-KBP201G (Mouser PN). Haven't tried it but same specs. These bridge rectifiers are common parts and shouldn't be a problem to replace. Also a Rectron MDA201G would be another one to look at. 2A 100V bridge rectifier in an appropriate case/footprint and pinout.

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Thanks guys. I'll try the Rectron MDA201G. It looks pretty much identical to the 3N254, same pinout, size and specs. Only diff is the 3N254 is max rated at 60amp vs 50amp for the MDA210G. 

The 621-KBP201G doesn't seem to be available soon from Mouser. 

Just found, the VS-2KBP01 looks like a new direct replacement from Vishay.

Edited by starcat
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This looks like a very nice case for a dual chassis design for the static CFA3.

PSU chassis: mount the kgsshvpssicfetsinglenewrightsws and kgsshvpssicfetsinglenewleftsws GRHV boards on the sinks together with goldenreference6d GRLV in the middle/front and a transformer in the middle/back. Might be even room for two GRLV and two transformers for total symmetry. 

Amp chassis: two balanced CFA3 boards mounted on the sinks. Will be pretty empty in the middle. The internal hight of 73mm might get tight but probably enough to fit the 63.5mm wide balanced boards; or mount them horizontally with some L-brackets. What do you think?

I think I might go for it. 

Chassis dimensions in mm are: outside W360xD270xH86, inside W280xD255xH73


Or just use single chassis with both CFA3 boards mounted on the sinks and a kgbhultraminipsv4 board in the midfront and a transformer in the midback. 

Edited by starcat
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Hmm, you might be right Jose, but the fins of the small enclosure Michael used above doesn't look like being much more of actual real estate... Btw, which one is it exactly? 

This might fit in the two balanced boards, the BH mini PSU and a transformer in the back. Bit too high probably but for the sake of bigger sinks. 

Chassis dimensions in mm are: outside W320xD315xH120, inside W220xD300xH112


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