Wow. That is a very dim look at things. I guess it can go your way and we put together a funeral of sorts?
Good lord it can not be that bad. It is a piece of audio equipment made for pleasure, not torture.
I think OP should have some fun and enjoy some kind of repair journey.
I know it can be a painful journey at times, I hear ya but does it have to be?
Good luck finding undertakers willing to work for $40 😂😂🤣I guess it can go your way and we put together a funeral of sorts?
I think the last person around here said it well, I think it was Pass, he said bla bla bla for fun.
When he said FUN, a tiny reset button tripped inside of my brain.
I don't like all of Nelson Pass' projects shared here. I think his fingers should be banned for eternity from touching or owning trimmer pots.
That doesn't stop me from deeply coveting some of his work.
The foundation of DIYAUDIO.COM is and always has been to have fun. After that, all else is secondary.
Delete this if it is thread-jacking or offensive.
When he said FUN, a tiny reset button tripped inside of my brain.
I don't like all of Nelson Pass' projects shared here. I think his fingers should be banned for eternity from touching or owning trimmer pots.
That doesn't stop me from deeply coveting some of his work.
The foundation of DIYAUDIO.COM is and always has been to have fun. After that, all else is secondary.
Delete this if it is thread-jacking or offensive.
Fun, yes, and, for me at least, learning.
I would love to have a pair of Aleph 1 🙂
...deliver me a pair of STASIS amps designed by NP. Big ones. Ha.
I love and relish all the work that went into that stuff like no other.
Physics became a part of the conversation with NP.
I love and relish all the work that went into that stuff like no other.
Physics became a part of the conversation with NP.
Last edited:
Fail to see why Pass was dragged in but OK. You have both the layout and the BOM so you can start measuring dimensions and designing the basic board. If you like you can decide to not use the voltage selector and add a mains filter or common mode coil to filter out today's garbage. When this preamp was sold there was a relatively clean grid and no Bluetooth, wireless, cell phones etc.
Tips: avoid the strange 90 degree PCB tracks angles. Definitely add as much 5 or 6 mm holes near hot parts as possible. Use the largest size heatsinks that still fit. Make sure fresh air can come in through the bottom of the casing. It would be way better to keep the toroid off board bolted straight to the chassis for heat transfer and cleaner design (if space permits). Or have the toroid on a separate PCB (again if space permits) with mains filter and connectors at the right side for shortest connections to the PSU board. Either choice will give more possible space around the hot spots and ensure longer lifetime of the new caps plus more even division of heat. Connect the casing to PE for safety.
Have fun with the drawing!
Last edited:
All other remarks aside. Waiting patiently for current draw numbers.
Regards,
Dan
Regards,
Dan
I too am waiting patiently - for my bench power supply 🙂
Please take full precautions, dim bulb tester and so on, assume the pre-amp main board caused the power supply to fail.
Use current limiting resistors and other methods to protect your brand new power supply.
After it tests okay, proceed with further tests to find the fault.
I would check all the output transistors and so on with a meter before supplying power.
Use current limiting resistors and other methods to protect your brand new power supply.
After it tests okay, proceed with further tests to find the fault.
I would check all the output transistors and so on with a meter before supplying power.
As Naresh mentions, if your new supply has current limiting, I'd set it to a tad higher than you expect. I wouldn't worry about the supply too much. If it is decent, it should handle a dead short and just go to current limit mode. And by all means share the results, if nothing else so the next guy with a Krell pre knows how much it pulls. And finally I applaud your efforts. It is DIY. I have been working to replace the control board in my carrier AC condenser. It has been more of a curiousity than anything else. The old board works, I just don't like the way it works. So after hours and hours I've got what I want and it works with just a few more tweaks to the software that I want for power consumption reports. Sometimes its the journey, not just the destination.
IIRC it's pretty damn tight for space in there, low height case as well. The psu case isn't built the same as the amp it's an ugly little steel box. Give it a new box, bigger and better psu, its not complex. Sure it'll hurt resale but the other option is a new pcb to fit original case.
True on both counts.
Indeed. Between the frumpy looks and the 8 ft long umbilical cord, I reckon Krell intended the power supply to be tucked away and out of sight.
This makes sense vs expending more effort and more money towards a diminished return.
Last edited:
Its value now is that of scrap metal. The difference in effort & time needed for either a 100% copy or an improved version is probably 0. Depending on China that may fluctuate +/-10%. As an audio investment banker I would invest and HODL on its future value. But keep an eye on the stock market!
How is the drawing coming along?!
How is the drawing coming along?!
Last edited:
Funny the leads I ordered on AliExpress arrived from Shenzhen faster than the PSU from Tennessee
I feel for you.....
The postal service here sucks as well.
Got 11 LP´s from Portugal to Denmark in 6 days.
Ordered at the same time ONE LP from Copenhagen (240Km´s away)......... arrived after two weeks 🤣 🤣
Okay folks, my new bench PS arrived! I connected power to the main preamp and (superstition trigger warning) I rigged up my new volume control with crocodile leads (because if I soldered it in, then the preamp would definitely 100% turn out to be completely ruined).
The whole rig is ready for power-on, and...
Power is on! No smoke or anything. I turned on the amp and popped a CD. Music plays!
Right after power on the pre was drawing over 1.5A per channel, but pretty soon the current tapered down to just a little over 1A per channel
Here it's pulling 1.06A per channel with music playing, although being Class A current draw doesn't budge one bit whether music plays soft, loud or not at all. I listened for about half an hour while checking and recording temperatures. The scratchy staticky crackly sonic artifacts that could be heard in the past seem to be gone now - I'm going to speculate that the old VC was responsible.
The pre is connected to a pretty low-quality system right now, just in case something went wrong, so I can't judge its sound quality. Tomorrow I think I'll connect it to my main system and we'll see.
About component temperatures... Not exactly what I expected. I observed inconsistencies that I think need to be addressed, but more on that later.
The whole rig is ready for power-on, and...
Power is on! No smoke or anything. I turned on the amp and popped a CD. Music plays!
Right after power on the pre was drawing over 1.5A per channel, but pretty soon the current tapered down to just a little over 1A per channel
Here it's pulling 1.06A per channel with music playing, although being Class A current draw doesn't budge one bit whether music plays soft, loud or not at all. I listened for about half an hour while checking and recording temperatures. The scratchy staticky crackly sonic artifacts that could be heard in the past seem to be gone now - I'm going to speculate that the old VC was responsible.
The pre is connected to a pretty low-quality system right now, just in case something went wrong, so I can't judge its sound quality. Tomorrow I think I'll connect it to my main system and we'll see.
About component temperatures... Not exactly what I expected. I observed inconsistencies that I think need to be addressed, but more on that later.
That is a relief, so you can move forward.
Put heat sink compound on the main board parts where heat sinks are attached, it dries out over time.
Put heat sink compound on the main board parts where heat sinks are attached, it dries out over time.