QUAD 405 V2 Clones - Suggestions or Experience?

I was thinking of trying 2SC5200N or 2SC6145. However I have not run any simulations and I do not have a simulation file for this amplifier. I am hoping someone else can offer experience and data. Both the Toshiba 2SC5200N and the Sanken 2SC6145 are fairly fast transistors. And both are available easily from authorized distributors.
 
I picked up a pair of JLH quad 405-2 boards but unfortunatly arrived damaged with bad transistors.

quad40522.jpg
I'm trying to source replacement transistors. The board uses 2sc5200 output transistors, which are okay. And uses driver transistors that are marked as KA1049Y, but on the board they are marked as 1659A. Are these one and the same?
I can't find a supplier for these in the uk, what can i use?
Thanks
 
My concern is the poor performance of the quad 405 board. It's not measuring very well, it's not reproducing square waves well.
I was hoping someone may have done the work and tried different transistors.
The output transistors are sc5200 which are modern and should be fine, but the kta series i have never heard of before, can't find much about them on the net, they seem unpopular and have been described as having poor performance in the one post they appear
Thanks!
 
I found 22uF UES and 10uF Silmic left over from modifying the DAC inside an AVR-3805 so I went ahead and finished the gain modification. The 22uF UES is on the top of the board and the 10uF is under the board.

Hi Can you show me the location of the 10 and 20uf caps, also the aluminium cap next to the input film cap has gone green, is this different from the stock
 
Hi, i recently aquired and assembled 2 quad 405-2 clone boards, my power supply is 43.5 volts as it was what i have, but also have one that delivers 53 volts can i use it or is 53 volts too much?

I used 53v without any problems. With the quad 405 boards i used almost 60v. More power, but the amp may runs a little hotter, with a possible reduced life expectancy - not much
 
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I have marked the two capacitors that I replaced with the UES and SILMIC caps. Do you have the same PCB that I have in the photo?

No. My pcb is slightly different, it has 2sc5200 output transistors, same driver transistors, with the remaining components being very similar.

Why did you use silimic for the central cap, wouldn't a panasonic fm which is good power supply capacitor and lower esr have been better
Are you using nichicon es, i thought this was non-polarised, the design calls for a polarised capacitor
 
I had the Elna Silmic left over from upgrading the power amp in my Denon receiver. It is quite likely overkill but is a very good cap. The Panasonic FM is also regarded as a very good cap.

You can use non-polarized capacitors in place of polarized capacitors. Just not the other way around. The Nichicon UES is a very good capacitor for the purpose. It was left over from upgrading the DAC in my Denon receiver.