MC-30 with variable damping kit

[Jose Jimenez]

Variable damping was kind of a design phase amplifier manufacturers went through. The designer of the AR-3 loudspeaker insisted the the best sound from a tube amp for his speakers was with an amp with a damping factor of 1. So Marantz model 8 and 9 and in this case the MC 30 had variable damping.

I heard a similar story from Henry Engle of EZ Teltronics one evening when talking about the early days. Hank went to an audio show and heard the AR line of speakers and thought that they would be a good addition to the products he sold. He checked the system setup and had those item currently in the store including the Mcintosh MC30 amplifiers. He placed an order and became a dealer. When the order arrived, he was eager to setup the system and tried to replicate the glorious sound and bass he heard at the show. No matter when he did it was to no avail. So, he called up Gordon and explained the situation. Gordon replied, "ah Henry, I should have told you sooner. Those MC amps had specially wound transformers!"

 

[Bill Ferris]

Were not MC-30, 60 amps occasionally specially requested specs ordered & purchased to be used by various manufactures to drive equipment shaker tables in the mid 50~60ties ?
Maybe these particular MC-30ties variable damping circuit was designed and offered by Mc. due to industrial manufactures specific requirements requests.

Just a speculative thought.

 

[ramjet]

Were not MC-30, 60 amps occasionally specially requested specs ordered & purchased to be used by various manufactures to drive equipment shaker tables in the mid 50~60ties ?
Maybe these particular MC-30ties variable damping circuit was designed and offered by Mc. due to industrial manufactures specific requirements requests.

Just a speculative thought.

They were used for shaker tables and other industrial applications. I know of one was used at a USN Calibration Laboratory near me (knew the man in charge). As far as the unit being used having variable damping I do not know. References in the Audio Cyclopaedia state that it was used "for matching the output impedance of a vacuum tube amplifier to the impedance of a loudspeaker" but continues with "The method is now obsolete". I restored an Altec A340A a few years ago and it had this feature.

 

[Bill Ferris]

They were used for shaker tables and other industrial applications. I know of one was used at a USN Calibration Laboratory near me (knew the man in charge). As far as the unit being used having variable damping I do not know. References in the Audio Cyclopaedia state that it was used "for matching the output impedance of a vacuum tube amplifier to the impedance of a loudspeaker" but continues with "The method is now obsolete". I restored an Altec A340A a few years ago and it had this feature.

Yes, I remember reading something back yrs. ago about that circuit in my 1975 purchased wonderfully informative Howard Tremain`s Audiocyclopedia.
That variable damping "feature" was also provided on, at least one of the Fisher boxcar series mono block late fifties era tube amps.

My next door neighbor B-I-L`s pair of "The Fisher" 100 boxcar one, that I electronically restored ~ 15 yrs. back does, and he keeps that "feature" disabled for obvious sonic improvements with the speakers he`s driving them with !

 

[ramjet]

Yes, I remember reading something back yrs. ago about that circuit in my 1975 purchased wonderfully informative Howard Tremain`s Audiocyclopedia.
That variable damping "feature" was also provided on, at least one of the Fisher boxcar series mono block late fifties era tube amps.

My next door neighbor B-I-L`s pair of "The Fisher" 100 boxcar one, that I electronically restored ~ 15 yrs. back does, and he keeps that "feature" disabled for obvious sonic improvements with the speakers he`s driving them with !

I sold the A340A because I didn't like how it sounded regardless of the damping setting.

 

[Jose Jimenez]

Gee. And all along I thought it was there to get that grandpa bass feeling.

 

[prww]

Yes, I remember reading something back yrs. ago about that circuit in my 1975 purchased wonderfully informative Howard Tremain`s Audiocyclopedia.
That variable damping "feature" was also provided on, at least one of the Fisher boxcar series mono block late fifties era tube amps.

My next door neighbor B-I-L`s pair of "The Fisher" 100 boxcar one, that I electronically restored ~ 15 yrs. back does, and he keeps that "feature" disabled for obvious sonic improvements with the speakers he`s driving them with !

Bill, Still have my copy of Audiocyclopedia, all 1800 pages. Bought it in 1975 also. Used it extensively as I was building my first set of monoblocs at the time. The guy in the store sighed when I wanted to buy it. Said this was the 6th time he sold his copy, and he would have to order another now. Excellent book, and I still look things up on occasion. Paul.

 

[Bill Ferris]

Bill, Still have my copy of Audiocyclopedia, all 1800 pages. Bought it in 1975 also. Used it extensively as I was building my first set of monoblocs at the time. The guy in the store sighed when I wanted to buy it. Said this was the 6th time he sold his copy, and he would have to order another now. Excellent book, and I still look things up on occasion. Paul.

Was my daily reader/reference from front end to the tail end for yrs. while teaching myself audio electronics repair.