Being new to tube amps,always make sure you have speakers hooked up to the amps,and correctly.If you turn on a tube amp without the speakers hooked up,It can destroy the output transformers.Others here hopefully can steer you on the correct path for hooking your gear up,plus preamp suggestions.
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Good advice from Hifitime.
I don't see any reason why a JC2 wouldn't be a fine match for MC30's.
Re hooking them up, I'm pretty certain that you can ignore the two sockets on the side which look like 8-pin tube sockets.
There is a conventional rca jack for connection to one channel of the preamp outputs. I think that is what you are referring to as "1/4 type socket," because it is approximately 1/4 inch in diameter. However it is more properly called an rca jack, to which a conventional interconnect cable is connected. The term "1/4 inch jack" is normally used to refer to one type of headphone jack, which is different than an rca jack.
The black terminal of the speaker would be connected to the screw-type terminal on the left side of the amp which is labelled "com." The red terminal of the speaker would be connected to either the 4 ohm or 8 ohm screw terminal on the amp, whichever is closest to the nominal impedance of the speaker. If the speaker impedance is somewhere in between (say 6 ohms), try both the 4 ohm and 8 ohm terminals and see which one sounds best.
If the amps haven't been turned on in several years or more, their ac power input should be brought up very slowly, over a period of at least several hours, using a variac. And when they are initially turned on, make sure that the plates of the large power tubes are not glowing red, which would indicate an internal problem that might lead to serious secondary damage if the amps are operated in that condition for too long.
Here are links to the manual and schematic:
Good luck! I once owned a pair of MC30's, and they are classic amplifiers.
To Almarg - thanks a lot....phew, some good advice from you two guys. I am glad I posted here. One thing - when I switched the amp on without a speaker hooked up the tubes did glow an orange/red color. Not sure if this was because I should have had the speakers hooked up or if it has been damaged before I bought or maybe because it has been stored for years.
Just looked on the amp again - what I referred to a the 1/4 inch socket is a pre-amp input. It has a hole that looks like a headphone jack would go into and has a large plastic ring around it with 8 smaller slits. Above this is an RCA socket (at least it looks like one) and it says 0.5v input.
Are you saying my speaker cables need to be with spade ends then? If so, good as I have some coming next week for my other equipment.
Some other related Qs - I am guessing these would be able to run my Ikon Dali 7 speakers. However, I have a pair of Magnepan 1.6 speakers arriving Monday and the dealer I bought them from (before I discovered Audiogon) says they would be perfect for the Maggies. Naive as I am I doubt they would as I have read that (1) Maggies need lots of power (2) Maggies are not a good match with tube amps.
Anyway, I know I have a mint looking pair of very old time pieces here that deserve to be cared for and to think they are almost as old as me adds a whole other dimension to them. I have bookmarked a guy by the name of Terry (forget his last name), well known in the Mc community and he is very highly respected regarding refurbishing/fixing any old Mc amps and I think my next step is to box them up (carefully) and have him service them if they need it.
Thanks a million Almarg for the advice.
Just to end, finding this site and forum has been fantastic - great people, tons of integrity (re purchases) and I find it amazing that people aren't out to rip people off given all the expensive gear around like so many other places on the internet. A place where a persons reputation and respect mean something to them - just lovely. Oh, and I will never buy retail again!
Thanks a lot guys
My guess (and its just a guess) would be that you did not damage anything by running it without speakers, because the main likelihood of damage occurs when a music signal is going through the amp, while no speaker is present. The open-circuit at the output, combined with abrupt changes in the signal, produce what's called inductive kickback which can damage the output transformer. With no music signal, there are no abrupt signal changes, aside from responses to any electrical interference that may be picked up, which should be small if any.
As far as the orange/red color is concerned, it's important to distinguish whether that is the filament at the center of the tube (which will glow that color normally), or the cyclindrical metal plate which surrounds the other elements in the tube, and which should not be glowing.
Connect the preamp to the rca jack labelled "0.5v input," and ignore the other larger socket (which is actually a tube socket, but in this case is intended not for a tube but for a special purpose input cable that could be used instead of the rca jack).
You can connect the speaker wires to the screw terminals either as bare wire, or with spade lugs (if the spades are not too big to fit, and some spades will be too large for screw terminals on vintage equipment).
The two things you cited about Maggies are basically correct; they typically need lots of power and they have impedance characteristics which, while not extremely difficult to drive, are somewhat less than ideal for an older tube amp. But on the other hand, if you don't listen too loud, and you don't listen at too great a distance, and you don't typically listen to music with wide dynamic range (such as classical symphony) maybe it would be within reason.
One final thought -- if you have occasion to remove a tube, it is good practice to lift it out by the base, not by the glass. Otherwise the glass conceivably could loosen where it is fastened to the base, and although it would probably continue to function that is obviously not good.
Thanks again Almarg - you have given me some hope. Can't wait to hear a tube set up (with my Dali Ikons) and compare the sound I have with my Nait Naim5i. By the way, I just picked up a great deal on a pair of Parasound JC1 monoblocks to drive the Maggies along with the JC2 pre-amp....and I already know that that would be a good match. I paid $2,400 for the pair of JC1s - very good deal. I am already preparing for a lot of very late nights in the coming weeks.