Krell Club

[Firebottle]

I've joined the Krell club:




Well... not really, just got something meaty to get my brain around.

[Pigmy Pony]

I've joined the Krell club:




Well... not really, just got something meaty to get my brain around.

You need to put two of them in the other room, your house is starting to tilt

[Opti-cal]

I've joined the Krell club:




Well... not really, just got something meaty to get my brain around.

Sounds like you've got a Krell of a week ahead of you Alan....

[Ali Tait]

That lot will reach critical mass shortly.

[JohnJo]

That lot will reach critical mass shortly.

Well, the table will

[Macca]

Sounds like you've got a Krell of a week ahead of you Alan....

Genius.

[Firebottle]

For those of you not aware of the heavy engineering in a Krell, these are the output straps

[Ali Tait]

Busbar output lol.

[Firebottle]

Putting this here as a reference for others. This is specifically for a Krell 50S but shows the general procedure.

The relays are mounted on the output boards but contact cleaning is possible without removal of the relays, but one particular specialist tool is required.
Shown is a modified stainless steel tweezer, one arm is bent up to provide a very strong but thin hook, the other is a diamond spatular used to do the actual contact cleaning.




Firstly remove the back plate, 4 torx screws.




Remove the two output bus bars to give access to the relay.



The speaker terminals need to be loosened as there is no give in the bus bars, to enable removal.




The relay cover now has to be removed using the hook to lift the plastic edge which slips over the retaining lug on the relay base.
This is the most difficult part of the job because of limited access, particularly on the blind side.




The return spring on the top of the relay needs to be disconnected from the contact bar, placing finger on the other end so the spring isn't lost.




The contact bar can now be lifted from the usual position to gain access to all the contact pads. Use the diamond spatula to clean the pads.




Reassemble in reverse order then repeat for the other channel. Ensure connections are very tight on reassembly.

[AJSki2fly]

I joined the Krell club with a KSA-80 about 4 months ago after PXing my 300B set in for it and some other gear. I did this after talking with Martin(Macca) and Alan(Firebottle), my main aim was to get more control of the bottom end and perhaps more depth/space to the musical presentation. My reasoning to make the change was that I suspected the 300B was straining to control the WB Vectors at sensible listening volumes, and at times was creating a muddied image, both Martin and Alan confirmed this was extremely likely.

The KSA-80 turned up just as I started looking for a Krell, it was at Audio Emotion and I had a long chat with Gary about it and its history, originally a demo unit for some time at a dealers in Edinburgh and then a single owner unit who owned 3 houses in Scotland and had 3 relatively high-end systems, the system the KSA-80 came from had not been used very much over 20 years and was in very good condition. So Gary and I struck a deal including a 6 month warranty.

The KSA-80 arrived and as reported elsewhere the instant I powered it up I was blown away by the musical presence and sheer power in the musical portrayal, to use the old cliché "It sounded more real", so success at last and a good match for the speakers.

All went well for a couple of months and then one morning I noticed a very low level buzz from both channels, this was not affected by volume in any way, and was still present with everything everything else off and RCA's disconnected. I measured this and the 50-100hz buzz was around around 40-45dB with the mic about 15cm from the speakers, I would add you could not hear anything when music was playing, only went silent and was very low level. Due to the age of the amp I contacted Gary and sent him recordings of the buzz, he immediately agreed it should be investigated and fixed, he was happy to get it collected but I requested that we used Firebottle(Alan) who has worked on several Krells and is an accomplished Electronics Engineer, Gary agreed.

So 3 week ago I took the KSA-80 to Alan's, and he quickly diagnosed that some capacitors on the power control board were nearing the end of there life, not expensive about £2 each for new better ones. Also and quite important was that the 4 main power supply capacitors were measuring at around 25-33% of what they should be, maybe the previous owner had used it more than he said or they were just degrading with time. These Caps are huge, larger than Coke tins with 2 per channel and arranged in a square with massive copper buzz-bars connecting them up across the top. They are rated at 100v and 47000mF, but Alan advised they are running 50v to support the required voltage and current. Alan identified some good replacements which were virtually the same physical size and these were ordered, they were fitted very quickly although Alan had to make some minor mods as the new caps required 6m nuts/bolts fittings not the previous 5m. Alan tested the Krell out and the buzz has abated somewhat and it sounded very good.

I managed to get enough fuel and had a 10l spare fuel can in the boot, so I went up to Alan's early on Monday morning to collect the Krell, this is a round trip of 330 miles and the first 1.5 hours of the journey was abysmal with torrential rain and the MX5 aquaplaning twice even with nearly new tyres rated at A for the wet, some of the worst driving conditions I have experienced for many years. Alan and I were very pleased as Gary at Audio Emotion had already settled the repair bill.

I got home and Sue and I carefully extracted the Krell KSA-80 from the MX5's front seat, it had been carefully packed in place with lots of old towels and resting at the front on some large wooden blocks in the footwell, and tethered to the seat with a webbing strap around the 4 lifting handles for safety. I set it up and powered on and the buzz has subsided greatly. I duly put on a favourite couple of tracks of Shpongle Codex VI and was immediately struck by how much more the depth and bass control had improved, on further listening I feel it has a even more open spaciousness to the presentation. Some would say it could be that it was just the first initial impact and impression, however I listened to the Flower Kings next and noted improved detail, depth and control of the low end IMHO.

So I am very pleased with the result, a huge thank you to Alan, a lovely chap who is very knowledgable and truly helpful. Hopefully the Krell will continue to please for many years now.