C33 contuinuing woes

LotusFool

LotusFool

Well-Known Member
I have just about had it with my C33. The pre amp spent the better part of the winter months of 2016 (my listening time) in a local shop where my tech was trying to fix a "hum" in phono 2. (phono 1 does not work at all)He gave it back to me after 2 months and said "he couldn't find the problem or hear it". I'd get it back home and there it was!! I took it to him again for another 2 months, and got the same story. He is not my tech any longer!

So in the spring of 2017 I drove it down to Audio Classics (a whole day drive for me) and dropped it off with them. After a few months I took another day off and drove down and picked it up. All was well, and then almost a year to the day later the' Hum" came back. I called Ryan and he said it was still under his warranty, so I shipped it back to Audio Classics this time. Two months goes by, and I find a nice used SOTA turn table for sale in N.C. so I drove down and picked that up. On my way home with the turn table, I drove by Audio Classics and stopped by and picked up the fixed C33.

When I got everything back home and set up and turned on, there was the "hum" in phono 2. I couldn't believe it! I told my wife "I don't think they even took the pre amp out of the box". I was crushed to think Audio Classics would do something like that. After dinner that night I has an idea. I plugged the turn table into phono 1. It sounded beautiful and was dead quiet! . Audio Classics had repaired phono 1 and not phono 2. I never thought to try phono 1 because that had never worked. My faith had been restored and I can't say enough how wonderful Audio Classics is.

So now in the past few days the C33"s phono stage has taken a shit again. This time the left channel's volume drops to practically nothing. I give up. I could send it to A.C. again, but this condition would probably not be under warranty because it is a different condition and fault. Even if Ryan did offer to repair it for free (and I wouldn't expect him to) I don't want to be down for another 2-3 months.

So I'm thinking of a McIntosh MP100 phono preamplifier. I like the idea of being able to use MM or MC carts, but my question is, could I come out of the MP100 using the in balanced outputs and put them into one of the C33's tape inputs? What ever I replace the C33's phono stage with has to plug into the C33 somehow because the output of the C33 goes into my amp, and I don't want to have to change IC's from amp to C33 and then to some phono stage. I hope this makes sense.
 
Been through similar situations a number of times. Just have to chalk it up to the nature of the beast and human fallibility. I've heard plenty of similar stories with current McIntosh products although the problems were to do with OS issues rather than audio related.

In any case, it's always a good idea to have a stand-in unit when something goes on the fritz. It doesn't necessarily need to be something expensive- just something to tide you over so the entire system isn't down when a unit needs to go on the bench. A receiver with separable preamp/main amp sections is ideal for such a task which can serve preamp, tuner and/or main amplifier duties.
 
Giving both of your techs the benefit of intermittants, the times that the C32 or C33 really bit me was caused by a cracker solder joint where the molex plug pin is soldered to the board.

This is why I always stress that they should be reflowed and stressed (flexed) while in circuit.

All the electrolytic caps should be replaced and it certainly doesn't hurt to replace the NE5534AN ICs, although they are seldom intermittant.

After many A/B comparisons by local C33 owners a complete restoration of their units offered a well realized improvement.....they are almost 37 years old with 20 year parts inside.

It would make no sense to use the XLR connections from the pre preamp......unbalanced would be correct to any line level input.
 
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have you unplugged the tone arm leads and left the phono jacks open on teh pre amp. does hum still happen?

if you have had a few places look at the C33, and not found anything, the hum problem may not be coming from the C33.
 
Get rid of it and buy a C48, job done......

Sell the C33, someone will pick it up that wants to spend the time on it to repair it properly.
I have a Sansui G9000 which was in pretty bad shape which I got very very cheap, if I was a take-it-to-a-tech guy, it would have cost many trips and moonbeams and ten times what I paid for it to get it running properly and solve a rather elusive fault, it would not have been worth it.
But I spent many many hours on it, hours that would have been difficult to charge out to a customer, but because I am a tech it was totally worth it to me to get a very thoroughly restored G9000.
Sometimes units have these kind of faults, and its just the nature of the beast.

I think this is your opportunity to get a new pre-amp, don't waste any more time and money on it. C48 on the horizon I think...
 
I called Music Direct this morning asking about a McIntosh MP 100 I saw in their catalog. I got a wonderful salesman on the phone (Bes), and he told me the MP100 would sound so much better than the C33 phono stage, and I was ready to pull the trigger, when he asked me about my own diagnostics, and question me if I had tried everything to determine if it was actually the phono stage in the C33 that was faulty. He said my 30 year old SME arm and the wires inside were also suspect.

Now I had a 16 track recording studio back in the day with a 24 track Mackie mix board and all the outboard equipment necessary and I know a thing or two about connection failures. In my experience either it was good connection or none, with no middle of the road. What was happening to the C33 was the left channel from the phono stage would drop to 70% volume, but not off! This did not sound like a connection problem to me, but it did to Bes.

So I plugged in my old turn table into phono one, which eliminated all the connections from the SOTA's cart, through the arm to the DIN, to the phono stage, and it was perfect!!! My C33 is fine! I'm so happy I don't have to replace it.

After dinner tonight I took of the RCA's-DIN plug from my old TT and put them on the SOTA and the problem is gone. I can't understand it, but apparently there is something in the 30 year old wire set that reduces the volume level, but does not eliminate it. Maybe next year I will up date to the MP100 when I can better afford it, and to be sure I will buy it from Bes because he helped me so much here.
Thank you all for all of your ideas here.
Rock on!
 
Audio Classic had a C100 listed for very cheap last week. I almost pulled the trigger on it myself just due to the price and it's good to have backup.
 
In reading everything here...

Ground loop hums can be from all sorts of things. It's our job to work through them with a proses of elimination.
 
LotusFool said:
I called Music Direct this morning asking about a McIntosh MP 100 I saw in their catalog. I got a wonderful salesman on the phone (Bes), and he told me the MP100 would sound so much better than the C33 phono stage, and I was ready to pull the trigger, when he asked me about my own diagnostics, and question me if I had tried everything to determine if it was actually the phono stage in the C33 that was faulty. He said my 30 year old SME arm and the wires inside were also suspect.

Now I had a 16 track recording studio back in the day with a 24 track Mackie mix board and all the outboard equipment necessary and I know a thing or two about connection failures. In my experience either it was good connection or none, with no middle of the road. What was happening to the C33 was the left channel from the phono stage would drop to 70% volume, but not off! This did not sound like a connection problem to me, but it did to Bes.

So I plugged in my old turn table into phono one, which eliminated all the connections from the SOTA's cart, through the arm to the DIN, to the phono stage, and it was perfect!!! My C33 is fine! I'm so happy I don't have to replace it.

After dinner tonight I took of the RCA's-DIN plug from my old TT and put them on the SOTA and the problem is gone. I can't understand it, but apparently there is something in the 30 year old wire set that reduces the volume level, but does not eliminate it. Maybe next year I will up date to the MP100 when I can better afford it, and to be sure I will buy it from Bes because he helped me so much here.
Thank you all for all of your ideas here.
Rock on!
Click to expand...

I dealt with Bes a couple of times myself. Nice guy, knowledgeable, and really tries to help out customers.

Glad you got it all worked out. Treat yourself to a new album or a good lunch. :)
 
So other than not pressing you to try another turntable as a source your local tech was right, he coudn't get it to fail as you described......
 
4-2-7 said:
Audio Classic had a C100 listed for very cheap last week. I almost pulled the trigger on it myself just due to the price and it's good to have backup.
Click to expand...
That would push you well outside of your comfort zone ...
 
4-2-7 said:
Audio Classic had a C100 listed for very cheap last week. I almost pulled the trigger on it myself just due to the price and it's good to have backup.
Click to expand...

A C100 as a backup sitting in the on-deck circle in case the first C100 ever has a problem.

I live vicariously through Dan and has gear and record adventures. :bowdown:
 
4-2-7 said:
:thumbsup:

@LotusFool

I'll pass on that C100, but really you should think about it, nothing but good things to say. It has a awesome phono stage in it also, this pre is outstanding.
Click to expand...
Great advice here:thumbsup: and I'm still glad I listened to the same great advice a couple years back when I went from my C33 to the C100. :music:
 
4-2-7 said:
Interesting so you had the C33 also, the C100 has a bit going for it.
Click to expand...

Yes and I still have that 33 in a secondary rig with it's 20wpc monitor amp doing a great job powering my klipschorns. I must admit I had my doubts about the 100 unseating the 33 for main rig duties but the advice here was spot on and likely the best advice I've ever received from Audiokarma on an upgrade.
 
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