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The appeal of retro hifi

James

Lord of the Erg\o/s
It's taken me a while to get my ass into gear in housing my vintage Pioneer amps properly, mainly due to the lack of racking real estate. So I haven't heard the C-21 and M-22 as a matched pair properly until today.

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In part, I had been perfectly happy with my Densen electronics driving the E-Xs, which require six channels of amplification. The stereo M-22 alone won't do. But since moving the E-IIIR back into place and reverting its wiring for single amping, this presented the perfect opportunity to give the C-21/M-22 a proper listen.

I have three words to describe the thirty-plus year old amps.

  • OH
  • MY
  • GOD

I'm not sure if it's the proper class-A circuit, fully discrete electronics or just my expectation bias, but it sounds remarkably good. Less grainy and less clinical than the very fine Densen B-250/B-350s, but seemingly more self-assured and, well, natural really.

I really REALLY like them with CD replay via Densen B-400XS. I imagine vinyl would sound even more beguiling. But it's early days. They've been playing for maybe 30 minutes. The preamp is stone cold and the power amp is barely up to temperature. More to report tomorrow, and maybe better descriptors than OMG.
 
Classic women rock too ;) Hi-Fi never had any dignity . Old basterds and crooks all along.
The thing is (it applies to women as well ) that they were designed to please not to torture or be a tool for sado macho audiopohools chasing the sound of one clapping hand ..
 
Maplin used to sell 'silent PC' fans 12V DC - use a dropper resistor to run it slow [200 ohms? I forget..] it is unnoticable in a PA amp 1 metre from my ear.
 
Excellent stuff James

The plan for a small fan is a good one for longevity. Picking-up demotivated's point you can run '12v' pc-style fans off a 7805 voltage reg just fine for less airflow but total silence. (you don't need a gale anyway, just a bit of air movement will help enormously)
 
Patrick Miller of Sugden once told me not to worry about the heat my A21Se generates and when I mentioned the use of a fan he said yes, by all means , if it makes you feel better.
Before being rebuilt, did the Pioneers show any signs of heat caused damage ?
 
Have been collecting it for years and still love it. Such stylish workmanship and the sound is superb, great for playing my collection of LP,s. Young people are quite amazed at the sound of my system, it may be bulky but if you have the room it is a status symbol. Also my Whirlitzer Juke box is an item on envy.
 
The pre has such clean lines and the power is almost industrial. Just the way it should be!

James, what are your thoughts on going multi amped back to two channels? I know it's difficult as the amps are different but do you think the more natural, less clinical sound may be due in part to the simpler set up and your well designed crossover?
 
Looks to me like maybe they should have left longer leads on the diodes to space them off the board.

Indeed, a common error, combined with putting to many hot components in the same area. Most Japanese equipment of this era seemed to have one weak area like this, as against most British equipment had several.
 
Looks like years of use with inadequately specified / cooled diodes to me.
Bingo. The diodes and capacitors were still fine, even if somewhat toasted. It doesn't help that the board is oriented vertically. The new diodes and capacitors are fitted with some gap to aid cooling.

The plan for a small fan is a good one for longevity. Picking-up demotivated's point you can run '12v' pc-style fans off a 7805 voltage reg just fine for less airflow but total silence. (you don't need a gale anyway, just a bit of air movement will help enormously)
That's what I have in mind. I've found a 120mm fan that is designed for low-noise (20dBA) that might just work. Rather than a voltage regulator, could this be simply plugged into an appropriately rated wall-wart supply?

http://www.jaycar.co.nz/productView.asp?ID=YX2574

Before being rebuilt, did the Pioneers show any signs of heat caused damage ?
No, that photo is the only obvious area. However, despite the massive heatsinks, the chassis and - through conduction - gets very warm to the touch after a couple of albums. I think a bit of forced convection is never a bad thing.
 
The pre has such clean lines and the power is almost industrial. Just the way it should be!
I do like the function leading form philosophy.

James, what are your thoughts on going multi amped back to two channels? I know it's difficult as the amps are different but do you think the more natural, less clinical sound may be due in part to the simpler set up and your well designed crossover?
I was comparing the sound to the E-IIIRs that were reset to single amping a few weeks ago. Incidentally, I could not detect a great deal of difference. Certainly not enough for me to sit up and pay attention or think that I'm missing something with the single amp configuration.
 


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