Jump to content
kevin gilmore

krell ksa5 klone

Recommended Posts

I'm no expert, but I'd just use the suggested parts. You're thinking of using these instead of LSK389 or 2N5564? I know this is generally not advised, but I got the 2N5564 on eBay from seller Top Chips. I've recently fully powered up and tested the amp prior to casing things up and the amp plays music. So the parts are legit? I have no way of telling. My guess is the amp wouldn't work at all if the parts were fake.

On another note, you do have to watch out with eBay - I tried to skimp on paying $12 x4 for the OPA445 and bought them on eBay. When trying them out in the PSU no voltage or close to none. I ended up having to go to Mouser with my tail between my legs and bought 'em there. Boom success!

Share this post


Link to post
Share on other sites

Please give a link to a good seller for 2n5564-5566 on ebay. Input assemblies affect the constant voltage at the output, the less it is without an integrator, the more likely it is that transistors are not fake. I have a lot of original BF256C, so I asked about the possibility of using them.

Share this post


Link to post
Share on other sites

Do you mean that the voltage across the test points will constantly change? In my case I set the voltage to 125mV via pot after the amp has been warmed up. It drifts a little but doesn't stay exactly at 125mV. Or do you mean the dc offset with OPA445 removed?

This is who I bought 2n5564 from...

https://www.ebay.com/itm/1PCS-New-2N5564-CAN-6-Matched-N-Channel-JFET-Pairs/392370230460?hash=item5b5b1694bc:g:wDEAAOSwvFNdSPV7

Share this post


Link to post
Share on other sites

Not sure, they might work.

I took a look on diyaudio. Not much discussion or mention of the BF256C. I did find this:

alternative transistors, not as costly as the Toshibas SK170 and much easier to source could be the BF256C and the BF246A/247A. The former is a bit higher in noise (still sufficient for highlevel circuits), the latter features much higher Idss which allows for larger source resistor values and for higher bias currents, which could be advantageous in output buffers and buffers that need to drive capacitive loads -which is a very common case with filters.

https://www.diyaudio.com/forums/analog-line-level/169005-jfet-active-crossover-3.html#post2227453

EDIT: and from earlier in that thread from the same poster:

well regarding soundjudgements aren´t easy, because everybody has a different taste. To me all OP-Amp filters I built sounded artficial to a certain degree. I never doubted to listen to a reproduction of music. The first discrete JFET-filter changed that. Now there was music a lifelike quality which sounded authentic. Music instead of HiFi. I know that distortion-wise the simple Buffer is very good, but dosen´t reach a OP´s low values. But the...who cares about distortion figures, which -as we know for 30 years now- don´t correlate at all with the sonic impression? Noisewise even the BF256C settles around -100dB, the BF246A, 2SK373, 2SK170 beeing even better. So noise should be no big issue. Hum can be an issue in every circuit and typically it depends alot more on the circuits surroundings than on the circuit itself.

A different thread, but doesn't sound promising:

https://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer-230.html#post2794067

I'd probably just go ahead and try them, observing pinout, but without the correct part or know equivalent, it might be hard to tell.

 

Edited by Pars

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...