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Kondo KSL-M77 phono preamp clone project

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#501
tomashans said:
use LT1963A reglator !

https://jimsaudio.com/lt1963a-very-low-noise-1-2v-20v-1-5a-6a-power-supply-pcb-w-soft-starting/

It is very good!

I have part for this boart and i can send you all oart for free if you pay shopping cost! ! If you are in EU i can send …
I have allso LT reglator ! You know if you want order part must you pay many money!
Click to expand...
I got the LT1963A regulator PCB. What heat sink are you using? I cant figure out what to buy. Perhaps if you still have the link from where you got it, it will help a lot. Thank you
 
#502
hesener said:
Just found out that my clone is showing a mysterious issue: When something is connected to the LINE input, but the input selector is switched to PHONO, there is a small but noticeable coupling that can be heard at the output (need to turn up the volume though). It is clearly coupling into the phono stage as the sound is muffled because of the RIAA correction. This is despite the input relays short-circuiting all other inputs when not selected.....

Anybody else have that problem????? Guess it could be solved by routing shielded cables directly to the relays, but I wanted to ask if anybody else has that issue.....
Click to expand...
Now I have removed the input connectiosn from the PCB, cut the traces right at the relays, and put shielded cables from the input RCAs directly to the relay contacts - issue is gone. Interesting how good the signals from the "other" inputs couple well into the phono section..... you have been warned 😀
 
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#503
Did you cut all the traces and replace them with coax?
The crosstalk between line-level inputs should be about 30+dB less bad, but it's still a concern.
The PCB trace issue was raised elsewhere; I was hoping it's not real, but it looks like I'll have to find my Dremel. 🙁
Thx for the heads up.
 
#504
Just about finished with my 2nd build of this for a friend, he picked out the clone chassis. I noticed it came with a .01uf cap, anyone have any ideas where this should go? Thanks
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#505
hesener said:
Now I have removed the input connectiosn from the PCB, cut the traces right at the relays, and put shielded cables from the input RCAs directly to the relay contacts - issue is gone. Interesting how good the signals from the "other" inputs couple well into the phono section..... you have been warned 😀
Click to expand...
Interestingly enough, was noticing the same with my unit. Didn't occur to me until I had multiple sources playing at the same time. I may need to try your mod out.
 
#507
Zung said:
Did you cut all the traces and replace them with coax?
The crosstalk between line-level inputs should be about 30+dB less bad, but it's still a concern.
The PCB trace issue was raised elsewhere; I was hoping it's not real, but it looks like I'll have to find my Dremel. 🙁
Thx for the heads up.
Click to expand...
yes exactly. Not coax though, but shielded cables, one for each input.

the obvious solution to the problem is to not have multiple sources play at the same time 😀
 
#514
Hi All,
I'm finishing off my build and about to buy the Valves but am thinking that I will only be using a maximum of two Inputs, do I need to put all 8 in or will it still work if there are only 6 (obvs the Rectifier valve is staying).

Cheers
Alan
 
#517
Thanks for the responses gents, I would like to try the Phono Stage at the very least, so think it will have to be the 8 Valves. I have a EAR clone phono stage I've built from threads on this site plus the Lenco site which I'm very happy with, so will be interesting.

regards
Alan
 
#518
My chassis for this project has finally arrived and I thought I'd just check here with previous builders: the simplest way of earthing the board and avoiding any hum loops seems to be by filing a little paint off the bottom plate, drilling a hole for an extra brass stand-off and fixing it to the earth point with a lock washer at each end. Any objections?
 
#519
hesener said:
Those resistors should discharge any DC coming from a source, as I have noted a clicking sound when changing the input. 100k in my case, but they can be anything maybe up to 500k.

Finally found out the clicking noise is caused by something else (relay decoupling)...... This can be cured with a diode in parallel to the relay coil, with the cathode to "+"
Click to expand...
Hello Hesener, which diodes should be connected in parallel to the relay coil to prevent the switching click.
Thanks for your information in advance.
 
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