Mixed driver tube for Mcintosh MC275

The Mark IV also has gold plated balanced inputs. The balanced inputs sound far more electric sounding IMHO in comparison to the natural sound of RCA's in any component. The balanced inputs have more gain but I am not sure that makes them better, different for sure. Some manufacturers still do not even use balanced inputs in their components. It was a major disappointment the new amp does not have the RCA's and attenuators. The lead free design is a good thing. I also think the old barrier post allow for a better connection, just not as many options. I could have had either but went with the older model so I can run a phono amp directly into the amp. I like this option. From what I am told, the mark IV and earlier models had their tranformenrs wound by the same person/people that wound the original models. Does anyone know if that is true?

I still have to say that putting a better tube in V1 does make a difference when using balanced inputs. It is not small either. You have to try it. Better bass and well, everything. I don't care what the schematic says, my ears tell me different. Take the stock tube out and put a spare tele in there and come back and tell me you do not hear a difference.

Tzh21y, do you know how to read schematics? I'm guessing you don't, because if you can make a statement like "I don't care what the schematic says" etc., then you'll never understand that there is a cause-effect relationship behind ALL audio experiences. Whether a person prefers one kind of sonic experience over another is their call! But that doesn't change the science.

I've used all kinds of 12AX7A/5751 tubes in the MC275 V-1 slot while driving the amp in BAL mode; and they don't have ANY effect on the sound; a result which understanding the schmatics would make clear for you; unless of course you subscribe to 'audio voodoo' ;--) And if you are in fact being sincere and objective (and good manners demands I assume you are ;--), the only explanation I can offer for your "experiences" it that you've got some 12AX7's with badly damaged filaments, gas or perhaps shorts!

Further, it's been my experience that when a listener says they sonically prefer SE operation over BAL operation, it's because;
1.) Some other hardware in their system is skewing the result for reasons contained in that hardware.
2.) Or the quiet and more accurate BAL operation is revealing some nasty condition or component elsewhere in the system that the less precise and less dynamic ("natural sound"?) of SE mode is masking.

My point here, is that instead of throwing up one's hands and pronouncing that the Gods of Science and Audio somehow or other work differently in THEIR listening room, it would be far more instructive (and productive of better sound) to learn some of the science behind the things we hear (both good and bad) and not just chalk it up to the weather or the color of the listening room ;--) I've looked at your system and would be happy to discuss these things in greater detail if you want to send me an email.

Neil
.

I spoke to McIntosh today and their tech support told me that V1 is definitely in the signal path when using balanced cables on the Mark IV so I now I know I am not tone deaf. According to Mcintosh, it is the circuit that determines whether you are using balanced or unbalanced. If you do not believe me, call them, they are easy to reach. I would like to see the schematics for this amp because I can read them. Are they available? Where would one find them? I know you can get the schematics for the original 275. So there you have it!

I know that I am not the only one that feels that RCA inputs sound better. I have spoke to others and they feel the same way. In the case of the MC275 which we are discussing, balanced cables offer more gain, otherwise, a waste of money. The MC275 is not a fully balanced amp so why would I want balanced inputs. If my amp was fully balanced, then it would make a difference, otherwise, it is a waste of money that I could use to buy records. I would not call it masking the sound. I also think the masking many hear is due to other factors such as the power cords. It is amazing what good AC power cords can do.

Tzh21y the balanced inputs on the MC275 have less gain not more as you stated in your last but one post.
MC275 gain: Balanced - 4 ohm = 16.8dB, 8 ohm = 19.8 dB, 16 ohm = 22.8dB
Unbalanced - 4 ohm = 23.2dB, 8 ohm = 26.2dB, 16 ohm = 29.2dB
These figures came from Mcintosh tech dept.

That may be true as I do not have the gain specs in my manual. It does say that the input sensitivity is 1.2 volts unbalanced and 2.5 volts balanced. The only time I would use XLR is if I needed to use a longer interconnect from the preamp to the amp. It is not a fully balanced amp so what benefits are there to the balanced connection other than if you need a long run to your preamp? it makes absolutely no sense other than spend more money that I could put towards more records.