Here it is attached.
You're welcome.
Do not hesitate to ask me. I will be available to help you if I can and know. Remember though, my present capabilities are limited🙁, but I learn quickly and a lot.🙂
I am also attaching Pinkmouses' BOM. Both of these files are somewhere in this thread but I wouldn't let you search for a needle in a hay stack. 😉
Which board do you use?
I have two schematics for Ground disposition, which is the correct?
Right theorical original
Left clone krell
Right theorical original
Left clone krell
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The both might be right (I mean technically correct) and original/clone Krell but the schematics below is better though low resolution. Correct values you may find in the accompanying text. There is a three part article on that subject - the best I have seen untill now.
My KSA50 klone is built using a pair of 51,000uF caps for each channel. I'm considering changing these to an CRCRC layout with 6x6,800uF and 3W 6x0R47 resistors for each channel.
The pair of 51,000uF is the classic PSU, I was wondering if anyone who had tried a CRCRC configuration could comment on the change to the sound.
Needs a box..
IMG_20200329_173055__01 by Garf Arf, on Flickr
Ta.
The pair of 51,000uF is the classic PSU, I was wondering if anyone who had tried a CRCRC configuration could comment on the change to the sound.
Needs a box..
IMG_20200329_173055__01 by Garf Arf, on FlickrTa.
Hy , Pleese one information , i have Delta audio circuit , For d201 and d202 1n4148 is correct diode? Thank’ s
Look at the upper right corner of the image below: the diode is 1N4148. It really looks small 😱 but is large enough. I have actually used 1N5408. Just zoom in >>the image <<< in my post on previous page to see how it compares by size to other elements, 🙂
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I've used the search function, but it doesn't deal with three letter acronyms very well.
(BOM).
Does any one have a BOM, bill of materials for Jim's Audio KSA50 PCB?
(You can see a fully populated Pinkmouse PCB in the background - since I have the original Krell KSA50 hardware, case, taros, heatsink tunnel etc, it makes sense to use the 1:1 clone PCB from Jim)
thanks!
(BOM).
Does any one have a BOM, bill of materials for Jim's Audio KSA50 PCB?
(You can see a fully populated Pinkmouse PCB in the background - since I have the original Krell KSA50 hardware, case, taros, heatsink tunnel etc, it makes sense to use the 1:1 clone PCB from Jim)
thanks!
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The both might be right (I mean technically correct) and original/clone Krell but the schematics below is better though low resolution. Correct values you may find in the accompanying text. There is a three part article on that subject - the best I have seen untill now.
I followed the advice on the TNT audio article and ended up with this..I added the bleed resistors 🙂
IMG_20200530_170032 by Garf Arf, on FlickrAnd finally finished off my Quasimodo board to snub the transformers..
2020-05-31_05-40-23 by Garf Arf, on FlickrLooking at the progress Chiily's made with his KSA50, I've decided to pull my finger out and get mine back on track again (and again ...)
Got a dilemma with the Krell trafos
The Krell specced toroids put out just over 40V AC with 242V AC in, so over 55V DC unloaded.
I'll have to accept less bias, change the heatsink and use more OP pairs or buy new power transformers. Or I may use a L-C-C type filter arrangement. Not sure if the L will be practical though.
The psu caps are rates at 80V, so no problems there.
Any thoughts on this?
Got a dilemma with the Krell trafos
The Krell specced toroids put out just over 40V AC with 242V AC in, so over 55V DC unloaded.
I'll have to accept less bias, change the heatsink and use more OP pairs or buy new power transformers. Or I may use a L-C-C type filter arrangement. Not sure if the L will be practical though.
The psu caps are rates at 80V, so no problems there.
Any thoughts on this?
Right, I have new found time for my hobbies, but my budget is limited-ish, luckily I've accumulated a load of parts already, over a span of about 12 years and counting.
I've decided to go with the Jims Audio KSA50 copies to re-create my Krell KSA50. Just to recapitulate, I'd come by original KSA50 chassis, trafos, heatsink tunnel and fan, bits of wiring loom, the original output transistors.
I have since bought 6 x 500ml beer tin sized capacitors (2008?), I have a selection of 50A bridge rectifiers, fast and fancy soft recovery diodes on a small PCB. I also have Pinkmouse PCB fully populated.
Output terminals and RCA input sockets. I have a load of TO3 On-Semi transistors when they were sending out samples, so I should be ok there.
I need to buy the components to populate the new PCB.
Where do I need to stick with top spec parts, where can I go generic? Without compromising too much.
Was going to go for Dale RN60D, but Mouser and RS have some values on backorder for 49 weeks ...
Any where else I can try? or another manufacturer? Not sure how important to keep to the exact values, especially for values like 9k09 for example. Bear in mind I'm located in the UK.
Do any of the transistors need to be matched?
I've decided to go with the Jims Audio KSA50 copies to re-create my Krell KSA50. Just to recapitulate, I'd come by original KSA50 chassis, trafos, heatsink tunnel and fan, bits of wiring loom, the original output transistors.
I have since bought 6 x 500ml beer tin sized capacitors (2008?), I have a selection of 50A bridge rectifiers, fast and fancy soft recovery diodes on a small PCB. I also have Pinkmouse PCB fully populated.
Output terminals and RCA input sockets. I have a load of TO3 On-Semi transistors when they were sending out samples, so I should be ok there.
I need to buy the components to populate the new PCB.
Where do I need to stick with top spec parts, where can I go generic? Without compromising too much.
Was going to go for Dale RN60D, but Mouser and RS have some values on backorder for 49 weeks ...
Any where else I can try? or another manufacturer? Not sure how important to keep to the exact values, especially for values like 9k09 for example. Bear in mind I'm located in the UK.
Do any of the transistors need to be matched?
As far as a know the amp is just fine with decent quality metal film resistors and have read the majority of this thread I did find anyone demanding that the transistors have to be matched.
I'm thinking of trying a couple of Cap Multipliers instead of the big 51,000uF caps on my KSA50, has anyone tried cap Mx's?
Juma's Easy-Peasy Capacitance Multiplier
Juma's Easy-Peasy Capacitance Multiplier
You might be interested in this The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
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hi .. I wanted to know if the 2sa968 / 2sc2238 must be selected and coupled for gain? thank you
Finding genuine 2SA968 and 2SC2238 might be a problem, but you should be able to find modern replacements.