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CAT SL-1 Reference repair

I recently bought a CAT SL-1 Reference preamp. The line stage is great. But the phono stage doesn't work properly. I crank up the max volume but it doesn't give reasonable listening level and it became too noisy. The sound is dry and week.  It doesn't balance well either.  I replace all the tubes in phono stage but without luck. Anybody has a schematic of this preamp? I didn't find anything on internet. Any suggestion is appreciated. Thank you.
cygnus_859
knghifi
1,668 posts
 
How about Ken Stevens?    585-359-2700
orpheus10
8,668 posts
 
If you bought it at a good price, sell it and buy one that works
sardonyxx
64 posts
 
Are you using a MM or MC cartridge? There are loading plugs for the MC's if they are low output.

bombaywalla's avatar
bombaywalla
1,958 posts
 
best to call CAT in upstate NY & have them repair it. They know their products well & can fix any of their old products.
You will never find a sch of any of their products on the web as they never release any of this info. All of their topologies are proprietary & many of the internal components are also proprietary. If you’ve opened the box you’ll see that none of the caps have any values on them - just a catalog number. The CAT factory has the decoder key to match catalog number to cap value.
Let the factory take a look & tell you what’s wrong....
excellent preamp, if i may say so.
czarivey
5,946 posts
 
 if you're onto DIY,
first, check if tubes light up on you phonostage.
2nd do visual on phono-board by checking any signs of burning or caps leak with magnifying glass
3rd if tube(s) light up, you have to measure bias current or voltage accross bias resistor of each tube. bias resistor can be found in grid circuit and the grid pins can be identified via internet just by querrying your tube ID.
4th, if you're local enough to raleigh nc, i can accept your unit and make it work and if not, unfortunately i don't do shipping turnarround. 

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