Powering off MC500 power amp

[tdelahanty]

If you think the autoformer has nothing to do with dampening factor you lack a basic understanding of electronics and amp design.

[Charles]

Originally Posted by tdelahanty

If you think the autoformer has nothing to do with dampening factor you lack a basic understanding of electronics and amp design.

I don't believe anyone is claiming that. Most tube amps have very low damping factors. I believe that when Mac came out with their solid state amps their aim was to duplicate the sound of their tube amps. I believe they did a fine job. Modern Mac tube amps have damping factors greater than 40. I really like Mac bass as I mentioned.

Modern Mac amps have plenty of current, both SS and tubes. Currently the MC3500 is the most powerful tube amp on the market and it requires no fan. The XVX Chronosonic is a massive speaker with a minimum impedance of about 1.5 ohms at 327 Hz. Its crossover is massive and holds a lot of current. Either my 1.25KW or my 3500 drives it with ease.

Interestingly, I can make my 1.25's sounds almost identical to my 3500's by going from an 18 dB/octave to a 12 dB/octave LP rolloff. I precisely matched the amount of gain in the sub for both sets of amps.

The 3500 has the best bass I have heard in any amp. However, I am not sure I cound discern between my 1.25's and my 3500's with this adjustment. I happen to prefer port to sealed bass because I feel port is more natural. I prefer "autoformer" bass because again I don't like overly tight audiophile bass. Extremely tight bass isn't for me. Everything is a matter of preference in the high end. One would think that the bass I'm describing lacks detail. Not so, the 3500 has the best detail, resolution, and nuance through my XVX, and yet maintains that naturalness I so enjoy.

I would expect the same performance through the MC500 but perhaps to a slightly lesser degree.

Best

Charles

__________________________________________________ _
Charles Updated System: Wilson McIntosh Audioquest
New gear on order:
Most recent updates: Latest is the last one posted: AQ Diamond USB replaces AQ Coffee; Wilson Audio Specialties Alexx replaced by Wilson Audio Specialties XVX Chronosonic; new subwoofer crossover; new Galaxy Grey Thors Hammer; Wilson Pedestals; heating and cooling completely reworked and reinsulated resulting in a much quieter, cooler, and more efficient room (cost about 10,000.00). McIntosh MCT 500 SACD/CD transport; Wilson Audio Acoustic Diode for XVX Chronosonic; WEL Signature digital Coaxial cable for MVP 881/D1100 digital connection replacing the optical connection; New plinth for Thor subwoofer made of X material with the Wilson Acoustic Diodes; Thor is now off my floor; MC3500MKII mono block amps (2) and two custom granite slabs; Wilson ActivXO Stereo Electronic Crossover; new 75-ohm multi-directional FM antenna for tuner
Amps: McIntosh MC3500MKII mono blocks (2), McIntosh MC1.25KW’s (3). All amps set on floor on custom made granite slabs
Preamp and DAC: McIntosh D1100
Sources: McIntosh MCT500 SACD/CD Transport, MVP881 BR player, MVP851 DVD player, MR87 tuner, Marantz 510LV Laser Disc player, ASUS laptop USB (JRiver Media Center 23)
Speakers: Wilson Audio Specialties XVX Chronosonic; custom made Wilson Acoustic Diodes
Sub-woofer: Wilson Audio Specialties Thor’s Hammer (1) horizontal lie; custom plinth of X material with Wilson Acoustic Diode feet; Wilson ActivXO Stereo Electronic Crossover
Cables main system: Audioquest WEL Signature speaker cables and balanced IC (preamp to amps); WEL Signature AES/EBU balanced digital IC for CD playback; WEL Signature digital coaxial cable for MVP 881/D1100 digital connection; Audioquest Diamond optical (1) for tuner, (1) for MVP 851 DVD player, and (1) for LD player for total of (3); Audioquest Diamond USB cable; McIntosh MCT cable for SACD playback; Dragon power cords (5 HC cords and 3 source cords for total of 8); Thunder HC power cord for MR87 tuner
Cables subwoofer system: Audioquest Redwood speaker cable (1); Wolf balanced subwoofer IC from ActivXO crossover to amp; Wind balanced IC from preamp to ActivXO; Hurricane HC (2) and Dragon HC (1) power cords
Power conditioners: Audioquest Niagara 7000 (1) and Niagara 5000 (3); (4) dedicated 20-amp lines with no. 10 wire straight out of fuse box
Isolation: Wilson Pedestals for D1100; MVP881 BR player; MCT500 transport; MR87 tuner; plinth for Thor subwoofer made of X material with the Wilson Acoustic Diodes
Cabinet: Double Custom Woodwork & Design (CWD) solid walnut cabinet on large casters; holds all sources and preamp; also, Niagara 7000; 11 feet minimum distance from speakers
Acoustic Treatments: Room and Echo Tunes
AC: Dedicated to this room only, an ultra-high efficiency and quiet recently installed Ruud split system 3-ton heat pump.

[tdelahanty]

I have used MAC amps in an industrial/military environment and have great respect for their reliability! I have also heard the big tube amps (in home stereo), I owned the MA7000 integrated (250 w) and never liked the warm and wooly bass.

[Charles]

Originally Posted by tdelahanty

I have used MAC amps in an industrial/military environment and have great respect for their reliability! I have also heard the big tube amps (in home stereo), I owned the MA7000 integrated (250 w) and never liked the warm and wooly bass.

tdelahanty, Respectfully, I think that all Mac aficionados would disagree with you concerning the "warm and wooly wooly bass" comment, regarding the MA7000 and Mac amps in general. In addition, you believe Mac amps are generally inadequate regarding current and you don't like autoformers. Mac is selling so many 3500's (a large tube Mac power amp) that they can't make enough of them to keep up with demand. I assume you sold your MA7000 for a good price and didn't lose much money, since it's going for around 6-9K used and only a few are even for sale. So you cut your loses and have found a power amp that better suites your taste. Congratulations.

Best

Charles

[tdelahanty]

I can only recall one other company using an auto-former output stage, Mitsubishi (Integra today). It was huge, heavy and monster power. It also had very cool meters. I'm not 100% sure about it being Mitsu, but I have a very clear picture of this amp in my mind. The concept was abandoned in favor of more modern circuit design.

The output transformer of a tube amp is a completely different device from an auto-former. A tube amp is meant to be high output impedance and derives its power from very high plate voltage (output tubes).

If you love MAC products that's fine. From my point of view, whatever I choose, I want to understand the design choices. I'm curious why other reputable manufacturers don't use auto-formers and choose to build amps with very low output impedance (high dampening factor) ???

[cleeds]

Originally Posted by tdelahanty

I can only recall one other company using an auto-former output stage, Mitsubishi (Integra today) ...

Integra is an Onkyo brand. I don't think it ever had anything to do with Mitsubishi.

[tdelahanty]

:thumbsup

Originally Posted by cleeds

Integra is an Onkyo brand. I don't think it ever had anything to do with Mitsubishi.

You are correct!!!!! Your memory is much better than mine

[Masterlu]

Originally Posted by tdelahanty

:thumbsup
You are correct!!!!! Your memory is much better than mine

Which begs the question is it 40 years experience or one years experience 40 times.

[tdelahanty]

I don't know, forgot the answer?????

[W9TR]

Damping factors over about 50 are irrelevant due to the DC resistance of the speaker voice coils themselves and the resistance of the speaker cables and terminations.