2. amps-preamps
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How do we remember 1970s amplifiers?

I would be curious to hear some of the memories and impressions associated with the following short list of 1970s amplifiers:

- McIntosh "first generation" SS amps, MC2105, MC2505, MC2300, MC250, MC2100
- Dynaco Stereo 400 and Stereo 120
- Phase Linear 400 and 700
- Bang & Olufsen "slide rule" receivers (i.e. especially blackface Beomaster 4000)
- Original Ampzilla (not Son of Ampzilla)

I've chosen this list mainly because they cover a wide range of approaches to solving the issues of early semiconductor technology, and they were all pretty mainstream products in the U.S. I'm excluding the Japanese receivers/amps not out of predjudice; it's simply that the circuit designs varied quite a bit with each model, and thus harder to broadly classify their characteristics.

I'm interested in impressions of both sonic and non-sonic attributes, and a preferred ranking of the above, if you like.
kirkus
phasecorrect's avatar
phasecorrect
2,013 posts
 
Curious....how is the Kenwood ka 6000 by modern standards?
orpheus10
8,668 posts
 

Either Hafler, or Dynaco could be transformed into true "high end" amps by simply substituting their existing parts for the best parts available today.

Successful businesses were created doing just that. When "Black Gate" capacitors were available, I replaced every electrolytic in every piece of equipment I own with Black Gates. That was with the exception of huge capacitors in power amps, but all other lytics in everything from reels to DACs were replaced with Black Gates.

If the replacement of a single part can upgrade a piece of equipment, imagine how replacing all of the parts would affect that piece of equipment. It's quite possible that some highly regarded "high end" amps are essentially "Haflers" or "Dynacos" with different parts.
pubul57
3,712 posts
 
"It's quite possible that some highly regarded "high end" amps are essentially "Haflers" or "Dynacos" with different parts." Amen.
magfan
1,583 posts
 
I loved my Kenwood...KA-7100 of the late '70s.

Good with my 12" 3-way JBL 4311 clones from RSL....(SoCal Boutique brand) and later with my first panels...some MG-1s.
Since I was poor, I did a snip/snip....solder/solder and attached cables with RCA male ends and used just the preamp for another couple years with my first bit of hi-power amp, my old Carver Cube. Worked fine as a preamp.....

I still know where the amp is. I gave it away to someone who NEVER used it. I'm going to ask for it back. If they haven't used it in 20+ years, it'll never get used. Maybe a recap of the PS would be in order before pluggin it in?
transaudio
96 posts
 
Some of those old designs were pretty good and while the art has moved forward on a lot of amp features (protection, thermal and short monitoring, metering) sound was quite good in many of them. Just listening to an old mac amp is a good example of this. That Audio Research (tube) amp line in the late 70's was darn good. Dynaco's too.

I think long term amps will mean less to the market as active speakers become more and more important over the next years. Older preamps will likely gain in importance-for the front end will be ever more obvious.

Brad

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