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.
Had a quick look on Mouser and it seems that NJW21194G is the "slowest" from all power transistors. (4Mhz) What you people think about it?
I picked up a pair of JLH quad 405-2 boards but unfortunatly arrived damaged with bad transistors.
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
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
Yes. I prefer Toshiba and Sanken but I don't see why the KTA1659 would not work. What is your concern about the KTA1659?
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 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!
Quad405 measure not ideal and sound really good. For the love of diy just build it and perform the famous mods by Keith. 🙂
Funny thing is that under founder Peter Walker all QUAD equipment was designed by measurement only.
Nowhere in the original Huntingdon factory was a facility/room to actually listen to what they made.
Nowhere in the original Huntingdon factory was a facility/room to actually listen to what they made.
NJW21194 is fine......given you don't need high Ft and assuming you can also accommodate the similar, TO247 package.
Do you think there may be any chance that the transistors are fake. Have you measured anything or heard anything.
What do you think about the resistors, there are a lot of them on the board, would changing them for posh ones make any audible improvements
What do you think about the resistors, there are a lot of them on the board, would changing them for posh ones make any audible improvements
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 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?
Attachments
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
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.
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.