McIntosh C-24 preamp

Tube Radio

Tube Radio

Super Member
I have two questions about my McIntosh C-24 preamp.

1. It has three broken slide switches and I decided to remove the front panel to look at them and see how hard they are to change. Two more snapped off and that's when it hit me how they probably broke.

One switch had been replaced and it also has the factory mod with the springs pressing against the control shafts.

So at some point the front panel was removed again and the three switches broke because the panel wasn't removed straight .

Is there any place other than McIntosh that has the proper or similar switch?

2. I noticed the left channel the treble seems a little off slightly at times.

What's odd is I can set the switch to stereo reverse and it seems to be right, although at certain times everything seems fine in normal stereo.
 
I refurbed a C24 a few years ago, the slide switches looked identical to those in Dynaco preamps, and several other period components.
 
Haven't ordered the switches yet.

Will do so soon.

Might use some screws nuts and star washers to secure the switches so that I can easily replace them in the future if needed.
 
Is it common for the switches on these units to break? Do you think for normal use? Or just the front panel not being put on right?

Also, do these preamps have lights behind the lettering on the facia? It seems like every picture of one I see lit up, only the power indicator light illuminates on the front.

I am curious because one popped up and I'm interested. Under the hood it looks nice and simple.
 
Only the power light is lit. The panel isn't unfortunately.

The switches can break off if the panel is not taken off evenly from both sides.

All the electrolytic caps will need to be replaced other than the main two caps if not already done.
 
I had a C24 and quite liked it. The switches were fine on my unit, mind you it was only ever opened up in the McIntosh Clinic or by my very good tech. I've not seen too many of them around though.
 
Mine was opened at some point by someone who didn't know what they were doing.

Found a shorted electric cap keeping one channel from working.
 
I had been having an issue of intermittent connections of some of the RCA jacks and just always ignored it since things worked most of the time.

When I found the left channel was doing it as well and that the left channel was unusually lower in volume most of the time I decided to fix it.

Saw the RCA jacks were all dirty on the outside.

I had some #000 steel wool so I used that to clean the jacks on the outside.

No more bad connections and I do believe the left channel is at the same level as the right now, but I cannot be sure as this flu has my ears messed up somewhat still.
 
Pio1980 said:
I refurbed a C24 a few years ago, the slide switches looked identical to those in Dynaco preamps, and several other period components.
Click to expand...

So apparently I have a device that uses the same switches and didn't know it.

Just disassembled a solid state Heath kit oscilloscope intending on making it a scope clock and while removing the DPDT slide switches I noticed they looked an awful lot like the ones on my C-24 preamp.

Just brought in a set of three to compare and they look identical (at least the style and length of the actuating handle looks the same) so it looks like soon as I get the time, I can replace the switches in the C-24 for a grand total of $0.00 :banana:

In fact I don;t think I have anything invested in the preamp other than the $10 I paid for it as I already had the other things I needed to fix the problem it originally had of a dead channel.
 
Thanks.

Yes it is a very nice preamp.

Recently wound up adding a TL-082 OP-AMP internally to the record output so that I can connect the record out to pretty much any impedance. Was necessary for integrating it with the equipment I have that records.
 
I was always surprised how much better the phono section of a C-24 was compared to a C-22. There was big difference in the performance below 300 HZ. The 24 was slightly noiser on line inputs than a 22, but the phono stage really surprised me. And if you adjusted the amp levels you could keep the noise from becoming an issue. Even a C-26 could be noisier than a C-22 line stage. That's why I waited for a C-28. Klipschorns and big Altecs were always a problem until you got the interface between the amps and power amps adjusted for best signal to noise ratio . Especially if you were using big power amps.
 
GEtubeamp said:
H

How did you replace the switches? I ordered new switches from Mcintosh and just disassembled the front panel. It looks like they are riveted in?
Click to expand...

The switches are riveted and need to be carefully drilled out to replace..

When my long time friend sold me his C 24 in 2004, the power switch was busted, and even though I had a bunch the same style slide switches, none of them had the extended length shank, so Audio Classics sold me 2 inexpensively.

In my big coffee table sized history of Mc. book, they say IIRC, the C-24 was Mc`s first SS preamp offering.
I used it for a few yrs. driving my sunroom`s MC 2205, until another friend, offered me his C-26 for an attractive price, as he wasn`t using it, and was getting ready to attempt to sell it on eBay about 6 yrs. ago after having me go through it to make sure it functioned properly per factory specs.
 
As I recall I drilled the rivets out.

Think I used new rivets to put them in.

Only thing I wish is that the front panel lit up like other McIntosh preamps.
 
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