McIntosh MC75 and SDA 1-C
zplyonz
Posts: 18
I recently got lucky and landed a pair of McIntosh MC75 tube monoblocks. Very, very lucky. The amps sound toe-curlingly good.
Anyway, after getting knocked out using them with my Klipsch Chorus II and Magnepan 1.6QL's, I really really wanna hook them up to my pin/blade SDA 1-C's. I am scared to death to try it, electro-numbskull that I am. I have done a ton of searching here and am beginning to think I can do it. Basically, I understand the concept of using a strappable monoblock, but the configuration of these amps is confusing to me. I want you guys to give me a push if you agree it's OK. Here's a description:
Each amp has the following speaker connections: Typical "hot" connections for 4, 8, or 16 ohms. But also two more: a "common" connection and a "ground" connection, which have a small metal connector between them. Here's what the manual says:
"A ground connection marked GND has been provided on the speaker connection strip. The strap between the terminal marked GND and the terminal marked COM is provided to ground the secondary of the output transformer to the chassis for normal applications. If it is desirable to have the secondary of the output transformer feed a balanced line, the strap between the COM and GND terminals can be removed. McIntosh amplifiers are designed to operate with the secondary of the output transformer either grounded or not grounded. the speaker output connections are fed from the secondary of the output transformer."
Sooo, do I just strap the GND to GND on the two amps? Sounds like I should NOT remove the little connector before doing it?
Anyway, after getting knocked out using them with my Klipsch Chorus II and Magnepan 1.6QL's, I really really wanna hook them up to my pin/blade SDA 1-C's. I am scared to death to try it, electro-numbskull that I am. I have done a ton of searching here and am beginning to think I can do it. Basically, I understand the concept of using a strappable monoblock, but the configuration of these amps is confusing to me. I want you guys to give me a push if you agree it's OK. Here's a description:
Each amp has the following speaker connections: Typical "hot" connections for 4, 8, or 16 ohms. But also two more: a "common" connection and a "ground" connection, which have a small metal connector between them. Here's what the manual says:
"A ground connection marked GND has been provided on the speaker connection strip. The strap between the terminal marked GND and the terminal marked COM is provided to ground the secondary of the output transformer to the chassis for normal applications. If it is desirable to have the secondary of the output transformer feed a balanced line, the strap between the COM and GND terminals can be removed. McIntosh amplifiers are designed to operate with the secondary of the output transformer either grounded or not grounded. the speaker output connections are fed from the secondary of the output transformer."
Sooo, do I just strap the GND to GND on the two amps? Sounds like I should NOT remove the little connector before doing it?
Post edited by zplyonz on
Comments
-
Those are some nice tube amps.
Have you contacted McIntosh and asked them what is the best way to do it?
Another alternative is to get an AI-1 interface for the speakers.
Good luck! -
If your 1C's are a certain serial number or later you can build an AI-1 isolation transformer interconnect which can be used with mono block amps and non-common ground stereo amps. As far as your question about the amps specifically, that is a question for either Mc Intosh or someone very, very well versed in both those amps and SDA's.
If you're serial numbers don;t fall within those 1C's that can be used with the AI-1 and you find from an iron clad source you can't strap the mono's, then you can't use them with SDA's.
If you post your Left and Right serial numbers I or someone else will let you know if they can be used with the AI-1 isolation transformer.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
Thanks for the replies. My serial numbers are past 7500 which puts my SDA 1-C's in the group of those which can accommodate a strappable set of amps. Just wanted thoughts on the Common plus Ground straps and config of these amps.
-
keeping the com to ground connection on each unit then strapping the ground from one unit to the other will assure common gound.
