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Vintage amplifiers that could challenge or approach current state of the art amplifiers

SirPaulGerman

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Did anyone mention the Harman Kardon

HK 725 and HK 770
I got mine becasue of this


It was under the radar, not anymore
too expensive now

hk7707.jpg
 

Neddy

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Similar to the 3BNRB I have (also for sale). Sweet amp, durable as heck.
 

Cbdb2

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If your giving out 20 year warranties you want it durable, one of the reasons studios liked them.
 
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restorer-john

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I think that this is the fourth time that I've looked at this picture. The most classy and elegant amp I've ever seen. Do you know the production dates of this amp?
1971/2/3.

Here's some details:


and here lots of details and historic pictures:

The most beautiful one IMO is this in HP colours:

1668932984092.png


 
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Ken Tajalli

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I would like to nominate the vintage Meridian 103D power amplifier from the 70s.

103_103.5front[4690].jpg

103[1064].jpg


103ps_internal[724].jpg

meridian103%5b4492%5d.jpg

103_power_amp[5037].jpg

The two trimmers would set the bias/DC offset.

There was the 103 poweramp (pictured above) which consisted of a chocolate sized amplifier box, a thick extruded |Aluminium case, powder coated in brown that acted as heatsink too. And the powersupply matching box.
The 103D (D= Dual power supply) had two powersupply boxes and an adapted cable connecting the lot together.
I think it was 30W per channel.
The D version, really sounded marvellous!
At the time, I preferred it to all Meridian offerings (103 and 105 monoblocks).
 
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restorer-john

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I would like to nominate the vintage Meridian 103D power amplifier from the 70s.

View attachment 244527
View attachment 244528

View attachment 244529
meridian103%5b4492%5d.jpg

View attachment 244530
The two trimmers would set the bias/DC offset.

There was the 103 poweramp (pictured above) which consisted of a chocolate sized amplifier box, a thick extruded |Aluminium case, powder coated in brown that acted as heatsink too. And the powersupply matching box.
The 103D (D= Dual power supply) had two powersupply boxes and an adapted cable connecting the lot together.
I think it was 30W per channel.
The D version, really sounded marvellous!
At the time, I preferred it to all Meridian offerings (103 and 105 monoblocks).

Pretty cool looking layout for its age. Rails (+/-) straight to the TO3s and what looks like a bodged in after the fact zobel with hand wound inductor.

And a simple thermal cut-out on what appears to be the common earth return for both L/R channels. It could work, but wouldn't be fun for THD fluctuations. I should look at the schematic to confirm.

Very nice design aesthetically, especially that FM tuner. :)
 

Ken Tajalli

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Pretty cool looking layout for its age. Rails (+/-) straight to the TO3s and what looks like a bodged in after the fact zobel with hand wound inductor.

And a simple thermal cut-out on what appears to be the common earth return for both L/R channels. It could work, but wouldn't be fun for THD fluctuations. I should look at the schematic to confirm.

Very nice design aesthetically, especially that FM tuner. :)
At the time, Meridian had just started up. Funds available were limited, everything hand built, in house.
At least it does have the zobel filters!
Bob Stuart being the circuit designer and Allan Boothroyd being the art designer, hence the original name "Boothroyd Stuart Meridian".
The matching 101 preamp was a modular design - you could buy MM or MC input modules for it.
It later used, one of the first generations of the 5532 opamp for TT input modules. Earlier ones were discrete.
 

Blumlein 88

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1971/2/3.

Here's some details:


and here lots of details and historic pictures:

The most beautiful one IMO is this in HP colours:

View attachment 244543

I had an O-scope with those colors since it was of course an HP. Did not know about this amp.
 

DSJR

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Pretty cool looking layout for its age. Rails (+/-) straight to the TO3s and what looks like a bodged in after the fact zobel with hand wound inductor.

And a simple thermal cut-out on what appears to be the common earth return for both L/R channels. It could work, but wouldn't be fun for THD fluctuations. I should look at the schematic to confirm.

Very nice design aesthetically, especially that FM tuner. :)
They weren't that good on the bench and Meridian messed around with their products too much during production (first hand experience of many demo units). Best not say more, but the beauty really was only skin deep as time went on...
 

Ken Tajalli

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They weren't that good on the bench and Meridian messed around with their products too much during production (first hand experience of many demo units). Best not say more, but the beauty really was only skin deep as time went on...
Do you have any of those bench results?
It would be interesting.
 
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restorer-john

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I had an O-scope with those colors since it was of course an HP. Did not know about this amp.

It's from that era where the US ruled the world in test equipment, build quality and overall fuggin' everything. I was too young, but the more I have learned, collected and restored gear, I reckon it was an amazing time. I mean, they built that amplifier in their downtime for their employees and it cost USD$325! That was a ton of money, but it was essentially a one off. With 400-500 out there, they are the equivalent of rocking horse chit. Rare is an understatement.

The Japanese were still copying, imitating and sure, improving back then and not unlike the Chinese of today.

But those companies like Hewlett Packard, we may never see the likes of again. Maybe, maybe not. I dunno. All I know (as an Australian) is when Americans decide they want to do something properly, nobody else comes close. I just hope they never forget that.
 

DSJR

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Do you have any of those bench results?
It would be interesting.
They were in the HiFi Choice books of the time. I'll try to scan them and post. The later units being changed were a subjective finding (I have experience up to the 500 series).
 

Ken Tajalli

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They were in the HiFi Choice books of the time. I'll try to scan them and post. The later units being changed were a subjective finding (I have experience up to the 500 series).
Scan is time-consuming. Just a photo or two with your mobile phone will do, thanx.
As long as it is readable.
Anything on 556? I have one and love it, would be nice to know.
 

DSJR

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Scan is time-consuming. Just a photo or two with your mobile phone will do, thanx.
As long as it is readable.
Anything on 556? I have one and love it, would be nice to know.
OK. We were on the way out with the brand by the time of the 500's, but I remember two samples of 506 CD player made several months apart heard fairly close to each other using similar gear and comparisons and one sounded dull and the other thin toned (this kind of thing happened in the subjective-only days of the late 90's). Mid period Linn Karik CD players were the same, the motherboards changed a few times in the mid 90's and results at the time I judged quite audible. The 502 'balanced' preamp was a delight and didn't change and the 501 RCA-only model wasn't so good in reproduction of reverb/acoustic, but it had a revision (not sure if it became a full mk2) and that sorted it out.

The thing is today, with a far more objective bent, it's easy to dismiss these subjective findings as nonsense and imagined and I can't dispute that at all. But I can think of a handful of UK makers back then who did seem to design and somehow 'voice' their products to get good subjective reviews. All this time, there were mid priced CD players by Denon for example, which held to pretty much neutrality (and have stayed the course because of it) and my preamp reference then was the Bryston BP25 (which I still maintain needed some hours after a cold start before fully settling down subjectively - my experience and opinion and I'm damned well sticking to it, so there! :D )


As for seriously good vintage amps which may compare well today, it's difficult. Bryston was mentioned earlier and I feel the 70's Crown/Amcron amps should be considered as well. Ken Rockwell has measured a few and 4 ohm loads apart (when protection can kick in), they're not bad at all still for fifty year old designs. I remain delighted with my inherited pile (IC-150's lightly serviced, D-60's and a cheap D-150 which needs the optional front panel to dress it up) and they seem 'honest' enough for my needs as my speakers don't dip below 6 ohms. Here's my actual power amp in all it's flaking paint glory from the ad. DC offsets well within spec and I haven't tinkered.

1504193764_8661.jpg
DSCF0592.JPG
 
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restorer-john

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OK. We were on the way out with the brand by the time of the 500's, but I remember two samples of 506 CD player made several months apart heard fairly close to each other using similar gear and comparisons and one sounded dull and the other thin toned (this kind of thing happened in the subjective-only days of the late 90's). Mid period Linn Karik CD players were the same, the motherboards changed a few times in the mid 90's and results at the time I judged quite audible. The 502 'balanced' preamp was a delight and didn't change and the 501 RCA-only model wasn't so good in reproduction of reverb/acoustic, but it had a revision (not sure if it became a full mk2) and that sorted it out.

The thing is today, with a far more objective bent, it's easy to dismiss these subjective findings as nonsense and imagined and I can't dispute that at all. But I can think of a handful of UK makers back then who did seem to design and somehow 'voice' their products to get good subjective reviews. All this time, there were mid priced CD players by Denon for example, which held to pretty much neutrality (and have stayed the course because of it) and my preamp reference then was the Bryston BP25 (which I still maintain needed some hours after a cold start before fully settling down subjectively - my experience and opinion and I'm damned well sticking to it, so there! :D )


As for seriously good vintage amps which may compare well today, it's difficult. Bryston was mentioned earlier and I feel the 70's Crown/Amcron amps should be considered as well. Ken Rockwell has measured a few and 4 ohm loads apart (when protection can kick in), they're not bad at all still for fifty year old designs. I remain delighted with my inherited pile (IC-150's lightly serviced, D-60's and a cheap D-150 which needs the optional front panel to dress it up) and they seem 'honest' enough for my needs as my speakers don't dip below 6 ohms. Here's my actual power amp in all it's flaking paint glory from the ad. DC offsets well within spec and I haven't tinkered.

View attachment 244562 View attachment 244563

What is that thing? A crown what exactly. I've never seen anything like it apart from a prototype.
 

DSJR

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Scan is time-consuming. Just a photo or two with your mobile phone will do, thanx.
As long as it is readable.
Anything on 556? I have one and love it, would be nice to know.
Hope these are readable - I'm no photographer and the phone although good for general snapshots, may not be up to this kind of work - Look at the distortion figures though - they'd resoundly fail if tested at this level here today...

IMG_20221120_123700359_HDR[1].jpg


IMG_20221120_123721878_HDR[1].jpg


IMG_20221120_123749755_HDR[1].jpg
 
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