Replacement for KSA-50


Hi Amp Gurus,
I have a KSA-50 that is 10 years old that has blown one channel. I use it to drive Thiel 3.5. Is it worthwhile repairing the channel or buying an used amp for less than $1000. Please let me know if there are any good options that provide the same quality as KSA-50.

Thanks,
smileallways
Your KSA-50 is a lot more than 10 years old. However, it is not likely you will find an amplifier that compares for $1,000. They don't make them like they used to. You have the real thing. Have it repaired and you will be happy for many years.
Well I owned the KSA-250 and it was a great Amp until one day it caught on fire. I had it fixed at Krell for about $1000 including shipping costs. That's probably what it will cost you to fix it.
I eventually sold it and bought a Pass Labs X350.5. Way better than the Krell.

I don't think you can replace your Krell with anything comparable for $1000.
"I'd buy broken one and fix it if your repair bill is too high."

That's a brilliant idea Marakanetz, buy another broken one, and spend money to fix that one. Lay off the egg nog.
Like to know what is wrong so we can help. It may be more than $1000 and then the other channel should be look at and parts updated. Hard to say without knowing the problem.
It is one of the 10 best amplifiers ever made and certainly the best Krell ever manufactured. I don't own Krell products as I have very well regarded tube amplifiers. However I am familiar with this amplifier.
Send it back to Krell and they will bring it up to new status and will also replace some worn passive parts on both channels and you will have an amplifier good for another 20 to 25 years
Hi,
Thanks for all your thoughtful comments. I am going to get it repaired. Speaker wires got shorted by accident. This caused one of the channels to stop working. Are there people in the DC area that can repair this amp without needing it to be sent to the factory. If the best option is to send it to the factory, I will do it. Please let me know.

Thanks again,
Perhaps you blew a fuse? Did you look inside for a blown fuse? Did your amp smoke, smell, etc... When this happened?
Yes, the Krell is great amp, but... those Theils wouldn't mind some more power, and FWIW, I never much cared for fans on amps.
I agree that sending the unit to Krell is probably the way to go. I noticed an ad for Krell MDA 500s that mentioned servicing by a company in Bridgeport, CT called The Service Department, a possible alternative, though I don't have any experience with them. Do check to make sure you haven't just blown a fuse, though.

While Unsound is probably right based on his longer experience with the 3.5s, I'll note that I did use a Krell KSA 50 Mk II for my Thiel CS3s for a while (till I sold them to get Duntechs) and in my moderate sized room (20 by 18 feet) it drove the Thiels with no strain. It's a lot more powerful than its power rating would imply.

By the way, I (and I think most of people who posted) am assuming that you are talking about the original KSA 50, and not the later KSA 50s. Is that assumprion correct?
Thanks Grannyring for your suggestion! It was a fuse. I have replaced it and it is working now.

While we are talking about my set up, I have another question. I have removed the equalizer that comes with the Theil 3.5 speakers as per a suggestion in Stereophile . Sound is cleaner now, but lacks bass weight below 60Hz or so. Question to all of you is what subwoofer do you recommend to go with this speaker to add some bass weight to the music.

Thanks for all your suggestions and help,
I think your better off using the eq. The eq starts boosting at 70 Hz, not an area where most sub-woofers do their best work. If you want to use a sub, I suggest using the 40 Hz setting on the eq. I don't think the eq really causes that much compromise, and the benefits far outweigh any disadvantages (which might have more to do with preconceived prejudice?). You can insert the eq into a tape loop of your pre, if you'd like to switch it out when listening to music without any sub 70 Hz sounds, but then you'll be introducing more things into the signal path.
Unsound,
Thanks for your comments. I have misplaced the equalizer during a move to a new place. I have read somewhere that Thiel suggests using any other equalizer available in the market. Do you have any recommendations for the equalizer in the market for this purpose.

Regards,
I'd keep an eye on e-bay. They show up from time to time there. After securing one, you might want to send it to Thiel for inspection. A bit of needed maintenance on the Theil eq's is not unheard of. Thiel tends to be very generous about doing such things. Using an off the shelf eq might work, but then you'll have many more switches in the signal path, most of which have nothing to do with your intended purpose. I think Thiel was originally suggesting that one could use some of the after market eq's such as the JP Labs Golden Flutes that were being marketed during the time that Thiel was making the 3.5's. Those can be quite difficult to find now. Before Thiel ran out of replacements eq's, I believe they were charging $600 for a replacement. Comparable quality in a cheap multi use off the rack eq would seem like a rather dubious effort in my opinion, especially considering your previously posted concerns.
Something for you to think about..... An amp with the age of yours and one that runs hot like yours will need the power supply caps replaced. This can be done by any competent repair shop or DIY guy. I have done this on severals amps. Understand it is time for this in your amp.

You may want to be proactive and do this maintance on both channels so they match. If you plan to keep this wonderful amp, then think of it as preventative maintanence much like your cars 105k scheduled maintence.

I see no reason you MUST send it to Krell. This can be done by a skilled local person if your luckily enough to have a shop near you. They can replace caps known to cause issues. May cost you far less also.
The Krell KSA-50 is a great amp also runs hot. It is a good ides to replace the four original 40000uF/75V filter capacitos with 47000uF/100V caps. I recommend either Nichicon 47000uF/100V or Epcos 47000uF/100V caps. Nichicon is made in Japan. Epcos is made in China. Also Cornell Dubilier 47000uF/75V caps made in USA will also work. Total cost $375.
Thanks for this tip! I will keep this in mind . Will this replacement do any SQ improvements or does it just make the amp less hot?

Thanks,
Yes you will hear a huge improvement in sound. Also using a higher voltage capacitor the cap will run cooler.