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Help me configure my MC30s

efhjr

efhjr

Can you be more specific?
OK, now that I've got an idea about how to use my MI-3 (thanks folks!), let's move on to my MC30s.

Here they are:

amps-back.jpg


They'll be fed by my C28, and they will power my Klipsch Cornwalls. And here are my questions.

Speakers -- I'll feed the Cornwalls from the 8-ohm taps. Do I use the COM or GND terminals. What's the difference?

GAIN and HUM ADJ knobs -- how do I set these? I'm assuming I'll do primary volume control via the C28.

Variable damping knob -- the amp on the left has a higher serial number, and it also has this switched potentiometer which the older amp doesn't. What is it, and how do I set it?

I've used these amps before and they sound quite nice (of course), but I've never used them with my C28, and I'd like to know how to best install them in the system. Thanks in advance for all your help.
 
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Gene,
You should tie the ground and common terminals together before you use them. They'll be more stable and quieter. Mine are that way at least.
My pair do not have damping pots so I can't comment.
Adjust the ac balance with the input shorted for the least amount of hum and noise.
Adjust your gain for equal output. A meter and warble tone is handy here. Dan
 
The amp with the variable damping knob is a "mc-30A". It is a little later version but very seldom seen. I have two of them in their original boxes but can't tell you exactly what years they were manufactured. Mine just came in and I have not done the full research on them yet.
 
Carl,

I am sure you have some fantastic equipment that would make many of us envious.

I do need to unload some of mine here shortly as I have one daughter deciding where to go to college next year. If it is out of state, I will have no choice unless some great scholarships come along with another daughter who is a junior. :tears:

It should be fun however as I am going to compare these wonderful MC-30A's hooked to a C-22 through a pair of Khorns, then my MC-225 through the same preamp and speakers. It will also be compared against a new MA-2275 integrated. So who will win the battle of my ears? Can the vintage surpass the new MA-2275? It should be interesting. All of the vintage pieces are in excellent condition so I am really having a hard time deciding IF I will actually rid myself of ANY of these. I also have a 240 and 275 so how much do we actually need?:dunno:

Anyway, I don't believe the two different MC-30's will have any conflict in your system and should sound great w/ your C-28. It looks like they are in great shape and in my opinion, one of the best sounding amps with efficient speakers. My suggestion is to play with the variable output switch and see if there is any discernable difference. If so, just turn it down and there should be nothing but enjoyment. I would also assume you would use the C-28 to control your volume. Just play with the gain adjustment to see what sounds best and adjust each amp accordingly. I am not technical so my method works for me. When it sounds good to my listening prference, that is where I leave the settings.

Let us know how it sounds once you get everything hooked up.
 
Gene,

also try the 4-ohm taps - to my ears the amps sound better on those when connected to my Khorns.

Otherwise enjoy your gear.

Wolfram
 
barrynsue said:
Carl,

I am sure you have some fantastic equipment that would make many of us envious.

I do need to unload some of mine here shortly as I have one daughter deciding where to go to college next year. If it is out of state, I will have no choice unless some great scholarships come along with another daughter who is a junior. :tears:

It should be fun however as I am going to compare these wonderful MC-30A's hooked to a C-22 through a pair of Khorns, then my MC-225 through the same preamp and speakers. It will also be compared against a new MA-2275 integrated. So who will win the battle of my ears? Can the vintage surpass the new MA-2275? It should be interesting. All of the vintage pieces are in excellent condition so I am really having a hard time deciding IF I will actually rid myself of ANY of these. I also have a 240 and 275 so how much do we actually need?:dunno:

Anyway, I don't believe the two different MC-30's will have any conflict in your system and should sound great w/ your C-28. It looks like they are in great shape and in my opinion, one of the best sounding amps with efficient speakers. My suggestion is to play with the variable output switch and see if there is any discernable difference. If so, just turn it down and there should be nothing but enjoyment. I would also assume you would use the C-28 to control your volume. Just play with the gain adjustment to see what sounds best and adjust each amp accordingly. I am not technical so my method works for me. When it sounds good to my listening prference, that is where I leave the settings.

Let us know how it sounds once you get everything hooked up.
Click to expand...

barrynsue,

Please post your thoughts when you have had time to do this comparison.

Thanks!
Paul
 
Dan, thanks for the input! I hope you don't mind some more questions:

How do I short the inputs?

Also, do I tie the ground and common terminals together with a jumper?
 
efhjr said:
Dan, thanks for the input! I hope you don't mind some more questions:

How do I short the inputs?

Also, do I tie the ground and common terminals together with a jumper?
Click to expand...

You could buy some shorting plugs to short the inputs. All they are is an RCA plug with the + shorted to the - (ground).

And, YES, tie the ground and common terminals together.

Your amps look very clean. Congrats!
 
TnT2 said:
Your amps look very clean.
Click to expand...

Thanks, Dan.

Well, I made some jumpers and tied the ground and common terminals together. Then I plugged the amps into the system, powered them up, and ... I got sound from only one amp.

So I turned off the lights and looked at the tubes. Dang, one of my Telefunken 12AU7s was not glowing. So I popped in another and I got music.

:music:

Holy cow, it's been too long. I've been using my MC2505 for power for the last year or so, and I had forgotten just how f**cking good these MC30s can sound. I dang near melted in the pool of rich, buttery midrange that came out of my Cornwalls.

And whoever says tube amps don't make bass hasn't heard Cornwalls driven by MC30s. As a matter of fact, I also put some of Herbie's Tenderfeet under the amps and I think they did a lot to tighten the bass and improve the sound of the amps.

I'm still getting some hiss, but I'll make some shorting plugs and fine-tune the amps. I need to rearrange all the power and speaker cords, too. But I cannot wait to get home and put on some music. I just bought some minty-fresh Nat "King" Cole mono LPs that are gonna be heaven played through my Lenco L75, MC30s, and Cornwalls.
 
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