So few remember the whole David Halfer kit thing. The Dynaco's were so good, Halfers were equally good to their time in SS. Hafler did OK but eventually got bought by Rockford Fosgate, who also owned Accustat. I forgot his name that designed all those Accustat TransNova amps, but (memory fuzzy) he was involved with Halfer later, wasn't he? I had an interview with Halfer in the 90's (they were all pro by then), in Tempe Arizona.
Hey anyone remember when Summer CES (high end suites) was at Hotel Congress in Chicago? That was about the early 80s and all those folks would be there.....the big companies where all at McCormick Place. In winter, it was Vegas and the Riviera for the high end and everything else was at (a much smaller) LV convention Center.
Brad |
Curious....how is the Kenwood ka 6000 by modern standards? |
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.
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"It's quite possible that some highly regarded "high end" amps are essentially "Haflers" or "Dynacos" with different parts." Amen. |
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? |
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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Eldartford brings up an interesting subject in that many of the amplifiers with more humble aspirations in the 1970s were capacitor-coupled . . . Johnnyb53 mentioned that his Altec integrated stereo had issues with reduced power output at 20Hz, which is a strong indicaion that it had an output capacitor. Most self-respecting "high-end" amplifiers, on the other hand, were DC coupled, possibly taking this to an extreme in the Kenwood L-07 that actually passes DC, and has DC gain. Crown was proud of this in the late-1960s; I think that the DC-300 got its moniker because it was "DC Coupled". And nowadays, this power-supply configuration is standard, and an output capacitor is an anachronism . . . ah, progress. But wait a minute . . . a quick re-examination of the current path in a typical "DC coupled" power amplifier (including even the L-07M), and the speaker is still coupled via capacitors - it's just that now they've moved from the positive side of the speaker terminal to the negative, and we call them "power supply filter capacitors". If their only purpose was to smooth ripple, there could be just one tied between the + and - rails . . . but then there'd be no way to return the loudspeaker current to the supply. The power-transformer's center tap does this in the case of faults and on startup (and for extreme subsonic noise/content on the L-07M), but most power amps can in fact purr along nicely with this disconnected, and no DC ground for the power supply at all. It's true that the "DC coupled" topology doesn't (or at least shouldn't) suffer from nonlinearities associated with the coupling/supply capacitors, the reason is that they are effectively inside the feedback loop, whereas in the "Capacitor coupled" topology they typically aren't. In the "DC coupled" scenario, there's still usually an electrolytic grounding the feedback loop (keeping DC gain to unity), and this can be a measureable source of distortion. So that leaves me wondering a bit why it was cheaper to build a capacitor-coupled amp in the 1970s? The extra cost of front-end transistors is tiny. You still need two big electrolytics, or three for a stereo amp, so it's actually more expensive in that regard. There is a bit of savings in the lack of an output relay and protection circuit, but that doesn't seem like enough to offset the extra big capacitor. This leads me to the conclusion that the real big chunk of cost was the talent to design an input stage with good offset characteristics, and perhaps the production technician to adjust the offset on every single amplifier, making up for the inconsistency in the semiconductors of the era. With an output capacitor, the whole thing is much more tolerant of both substandard parts and design mistakes. Now that transistor quality has improved dramatically, and there are plenty of existing designs to plagarize . . . those costs are much less significant for inexpensive systems, and capacitor-coupling has fallen by the wayside. 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. Indeed it was . . . and the idea of swapping in fancier parts to "improve" them to today's standards has some appeal. There's of course usually plenty of room for sonic improvement by simply correcting the ravages of 30-40 years of age, and technology and manufacturing of all electronic parts has moved forward innumerably in the past few decades. But the parts themselves are certainly NOT the real story, and the real improvement to be have comes from applying a modern design perspective to the older circuits, and making major or minor tweaks as needed. Some of them end up being pretty amazing just as they are, and others . . . well there simply aren't enough Black Gates and teflon caps in the world to help. |
It was 1978, (in Sweden) and I just got my first job cooking in a restaurant.
No debt, and nothing to spend my cash on "Forced me" to check out the stereo store in the neighborhood. Wow I loved it, the smell of warm amps and the big
VU-meters pulled me in to it's warm embrace. I think I spent more time in the store then the owner for the next six months....LOL
One day the owner come up to me and said, why don't you buy a system and you can enjoy some tunes at home. I walked out with Magneplanar Tympani 1D's,
two Sansui BA3000 amps and matching pre-amp, and the turntable was the
Micro Seiki DDX1000 with two tonearms.
I still remember how fab that system sounded, and I just bought the DDX1000 a month or so ago to revisit my youth. If I can only find two Sansui
BA3000 in mint condition I'll be in heaven :-)
Peter |
Peter53, will finding those old amps not just be an attempt at capturing lost youth?
Nostalgia for any of the gear that gave us our first glimpse at what was really hidden in the grooves I think is more like it.
Because a certain speaker or amp was a milestone,somehow some folks think it still will be today.
I have friend who has gone that route, thinking the best was all behind him.
He set out on a journey to replace all his newer gear with gear that he used to own.
Hoping to find audio nirvana once again.
All he found were the reasons why he let that gear go many years ago. |
I remember going from a Dyna 416 to a David Berning ea 150 to use with Magneplanar Tympani 1-C speakers and being blown away with the difference. The shrillness of the dyna compared to the Berning was unbelievable. I still have that amp and it is competetive with a lot of modern amps. |
- Acoustic Research integrated with AR5s. Solid state sound hard and glarey. Gave SS a bad name (which it deserved)
- Dynaco ST 120 - more of the same!
- Crown IC 150 and D150 driving Infinity 2000As - World class speakers even today and beautiful looking pre and amp but op amps and boatloads of negative feedback = bleeding ears + empty wallet!
- Phase Linear 700B- Much better but still electronic
- Phase 400 - better still and actually nice with beefier power supply caps. driving T-1Ds (needed ARC!)
- Hafler 100 & DH200 - actually not bad and better pooged. |
Hi Lacee...
You are most likely right about the "we left it behind" and should really not go back there. But with that said my new DDX 1000 (after a lot of upgrades) sounds
fantastic, although it cost me thousands of $$$ to get there..LOL
My new speakers are coming in a few weeks and I'll decide if vintage is the smart
way to go... :-) |
I've owned the MC250 - the industrial looking 50WPC amplifier. It uses autoformers and actually sounds fairly tubey. Good bass, a little muddy in the mids, and a not very detailed treble. It had a bit of a grainy smear to the sound - at least with the speakers I had at the time. But still, it was a very enjoyable and musical amplifier, just not very high-end.
I've also used a (rebuilt) Dynaco ST-80. Like the ST-120, it's actually capacitor-coupled to the speaker, so some of the faults could be attributed to the bad electrolytics of the time. The only I rebuilt had modern caps and sounded half-decent. Certainly not world-class, but a nice little dorm amp or something for a second system. Again, it just had a slight grain and a slightly forward/etchy treble. |
Well, my Flame Linear blew up, as did my dyna 120.
Having worked my way thru the dyna line, and going by their reputation only, I rushed to sell my Mk 3's for the newer better solid state - big mistake, the magic went. |
I also work in the hi-fi business and have been fortunate enough to change bits and pieces as I went. My very first system was an Apt Holman preamp / HK Citation 19 amplifiers (a pair bridged mono 220w/ch), a Micro Seiki MB15 / Micro Acoustics entry level cartridge with a pair of Yamaha NS100 monitors. I spent quite a lot of time listening to music back then!
Times have changed as well as the sophistication of my systems but the 70's was a fantastic time in audio! Loads of fun. Thanks for the trip down memory lane. |
I had a Dyna stereo 120 which had substitute transistors and never blew up. I used them on Rectolinear III speaker. I had the Phase Linear 700 with the Dayton Wright Electrostatics and the Watson Labs Model Tens. I also had the Ampzilla with Infinity 2000As. It is hard to say which of these gave the best sound. Probably the Watson Labs and PL 700. I never had any problems with the Phase Linear. I sold it to a disco and they blew it up in less than a month.
You neglected to add the Stereo 70, the Audio Research Dual 50, 51, 75A, 76 amps, and the Paoli 60M amps. The Dual 75A and Paolis were great on my Infinity ServoStatics. I keep this combo for five years.
This was a fun period for me with young kids, Hobie racing, and great sea food in addition to some good audio. |
My system in 1976 would probably still sound pretty good by today's standards. Here's the lineup:
Table #1--Rabco ST-4 with ADC XLM
Table #2--Thorens TD-124 with homemade pivoted arm and Decca Mk 5
Phono---homemade based on Trevor Lees circuit (supposedly a copy of the Paragon 10)
Linestage--homemade passive (pot in a box)
Power amp (100 Hz and above)---Dyna 70 with extensive mods
Power amp (below 100 Hz)--Williamson Twin-20 (Audio Amateur magazine project)
Speakers---KEF B200 in homemade transmission line; Fulton FMI-80 for mids; RTR ESR-6 electrostat tweeter |
Salectric, Your speakers sound like the Fulton Premiers which I had in the late '70s. |
Tbg, I would have loved to own a set of Fulton J-Modulars or the later Premiers, but they were way out of my limited budget. |
Salectric, I must say that I heard them when Fulton visited a local deal when I lived on Long Island. He played them with his "amp in a trunk." They were great, but the amp never became a product. I ended up with three pair of Luxman 3045 mono block amps, which had to be rebiased hourly. I gave up and bought double Quad 57s. Before I moved to Texas I had an offer to sell them, which I did.
Yes, I was going through equipment quickly at that time and finding little that satisfied me. |
I liked the Tandbergs. THese were among the best I recall hearing in those daysin terms of overall clarity and listenability. Even the tr2080 receiver's amp that I had up until a couple years back had a lot of top notch positive attributes. Its limitation was current delivery into more challenging loads, but this was a receiver not a separate power amp. I would like to own a vintage Tandberg amp in good working order again someday. |
I had a set of Fulton J-Modulars as well. For a long time I ran them with dual modified Dyna ST-70s monostrapped until I got my own amp going. Fulton was a local so I spent time with him at Bob Fredere's house in Minneapolis, which is where I first met Bill Johnson of ARC (I had a D-51 for a while also...).
I also ran the Rabco- an ST-7 that I had modified with a new servo circuit and a carbon fibre rod for the arm tube (hi tech back in those days), mounted on a Technics SL-1100. |
i heard that the phase linears were the king of frying speakers!! |
g_nakmoto,
I have to say that back in the 70's I was a Phase Linear user and was surrounded by others who used Phase Linear. I remember the sound being wonderful, fast and clean. Amps that I owned were the 400 series's One and Two. Never a problem. My friends owned 400s, 700s and one used two D-500's. We ran them hard and never had a problem not ever.
I even used a 400 to run a PA system for my band. Now it wasn't built like my McIntosh MC-2300, but then nothing at the time was. Still all this Phase Linear bashing? A Phase 4000 preamp and any of the above mentioned amps makes a sweet little system that will drive anything. With regard to frying speakers, I can't remember that happening either.
I like most have moved on but I know if I had too I could live with any of my old systems, Phase, Mac, GAS, Citation, Levinson etc. I have re-discovered my Sansui 9090db a few years ago and haven't been listening to anything but it. Seems to do everything just about right.
N |
Crown DC-300A Power Amplifier
Also Heathkit did make some good equipment |
I know it sounds crazy, but the PL700 I recently purchased out of curiosity (original series, w/factory-recommended mods done in the late ’80’s), fed directly from my Sony DVP-S9000ES SACD and running my Dunlavy IV’s, just wipes the floor with my Threshold S500 S2. PRAT is off the charts; it makes the Threshold sound dull and lifeless in comparison. I’m hearing subtle details in the music that the Threshold doesn’t reveal. Dead quiet amp. No sibilance or harshness, even at high volumes. This amp just makes beautiful music.
Bettered my VTL ST-125 as well. Very similar to my VTL TT-25’s in the mids and highs (and that’s high praise indeed).
I wonder how many people who go around poo-pooing these amps in some of the PL threads have even heard one in a decent system in the last forty years?
And FWIW, I’m a semi-professional trombonist, not some hack with wooden ears...
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I had a Rotel 1412 integrated that could be used as a pre or power amp. Sounded great with JBL monitors.
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chuxhifi,
Doesn't surprise me. A friend ran two D-500's bi-amping a pair of the original AR-9's. Sounded amazing. I could easily live with my old Phase Linear gear. Enjoy the 700. It's a wonderful little amp.
The damping factor on the 700 is 1000. Your woofers love that type of control.
N.
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Kirkus - truly great thread here. Enjoying reading all about this 70's gear. This was a little before my time getting into high end. Back in the 70's, I was still with my HK 330c receiver not getting into separates until in the mid 80's.
Actually an interesting neighbor let me hold onto his Dyna MKII amp, Mac C22 pre, MR71 tuner, and Thorens TD124 TT w/SME tonearm in the late 70's. Not knowing a thing about tubes back then, I turned it on and wondered why it didn't come on immediately and why it sounded so terrible after 5-10 seconds and ran so hot. I gave my girlfriend the TT and she said, "what is this POS?" If only we knew......
Wish they had a long discussion like this about 1980's gear. That is my go to era in audio and when I made lots of purchases...... |
Strongly agree Apt Holman pre-amp and matching amp (I have that pre-amp driving two of their amps running as mono-blocks).
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