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Classic Integrated Amplifiers!

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Kenwood KA- 7002. It was my second ever piece of HiFi gear. Replaced my Kenwood KR-4140 in my senior year of college (1972). Had it measured at a McIntosh clinic at the audio store I went to work for after graduation. FR was flat and both distortion and noise were low. Lovely piece of kit.

I had the power amp version, the KM-8002 -- it had a lot of features usually found in integrated models like Ken's KA-7002, e.g. a line-level input selector, terminals and switching for three pairs of speakers, and a headphone jack. Those amps were among the first to have DC-coupled output stages, which was a major advance in amp design at the time. Like Ken, I took mine to a McIntosh clinic and it acquitted itself admirably. I think the solid performance of those 1970s Japanese amps was one of the (several) reasons McIntosh stopped testing non-McIntosh amps and eventually stopped holding those clinics -- it was sort of embarrassing that such relatively low-priced imports was performing pretty competitively with their "high-end" counterparts.

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I had the power amp version, the KM-8002 -- it had a lot of features usually found in integrated models like Ken's KA-7002, e.g. a line-level input selector, terminals and switching for three pairs of speakers, and a headphone jack. Those amps were among the first to have DC-coupled output stages, which was a major advance in amp design at the time. Like Ken, I took mine to a McIntosh clinic and it acquitted itself admirably. I think the solid performance of those 1970s Japanese amps was one of the (several) reasons McIntosh stopped testing non-McIntosh amps and eventually stopped holding those clinics -- it was sort of embarrassing that such relatively low-priced imports was performing pretty competitively with their "high-end" counterparts.

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That's a gorgeous classic there. And absolutely true, it has a bunch of features you rarely see on power amps. Switchable inputs, individual polarity switches and headphones.
 
My only system: 1976-1978 trifecta of Yamaha CA-1010, NS-670, YP-511
With 1990 thrown in: NS-1 Classics, YST-SW500
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May not have s/n, SINAD, flat frequency chart topping specs but it can time travel!
I always smile putting on an album my parents bought in the 70’s because it sounds as if they never stopped playing their music 45+ years later….one very long listening session.
You have good taste in music.
 
Meters.
Proven to improve how an amplifier sounds.

If Ramsey said "you eat with your eyes first,"
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perhaps you listen with your eyes first also, lol
 
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I bought a pristine Technics SU7300 last week. Mainly because it was £30 but also because I remember having one before and thinking it was better than I'd expected.
So, taking things a bit more seriously this time, I've compared it to everything I currently have: Rega brio, Roksan K2, Cyrus 8xp and an Aiyima A07 max, amongst others.
This is an astonishingly good amplifier! It's clarity, soundstage, looks and sheer listening pleasure beat each of the above imo.
I'm a bit shocked as I've always thought of vintage mid end stuff as a bit of a novelty.

This is completely subjective and only based on listening tests but I'd say although both the Cyrus and Roksan are better at certain things (bass definition mainly) it's honestly not by an awful lot.

The aiyima in particular sounds dry and weedy now.

Sorry for the long post-just not sure where else I might get interesting feedback.

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I still have this classic Kenwood Supreme 600 combo gathering dust. Drove a pair of QUAD ESL-63s, also gathering dust. Nothing quite like the feel of solid metal milled knobs and switches, no plastic here. I should put them up for sale, I suppose.

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Yes you should!, or have them Cleaned /Restored and just USE them that's what i would do, beautiful looking kit:D
 
I bought a pristine Technics SU7300 last week. Mainly because it was £30 but also because I remember having one before and thinking it was better than I'd expected.
So, taking things a bit more seriously this time, I've compared it to everything I currently have: Rega brio, Roksan K2, Cyrus 8xp and an Aiyima A07 max, amongst others.
This is an astonishingly good amplifier! It's clarity, soundstage, looks and sheer listening pleasure beat each of the above imo.
I'm a bit shocked as I've always thought of vintage mid end stuff as a bit of a novelty.

This is completely subjective and only based on listening tests but I'd say although both the Cyrus and Roksan are better at certain things (bass definition mainly) it's honestly not by an awful lot.

The aiyima in particular sounds dry and weedy now.

Sorry for the long post-just not sure where else I might get interesting feedback.

View attachment 397754
Damn £30 for one pristine Technics SU7300 it's just to congratulate. It is also stylish. :)

If it is possible to hear any difference between your amplifiers, I am guessing that it could perhaps be that the Technics SU7300 only has a damping factor of 20 (4 Ohm) that affects that. Maybe, but that is just a guess on my part. It also depends on which speakers you have.

Aiyima A07 max is load dependent which I guess Technics SU7300 is not. That, depending on the speaker, its load, can make them sound different. Note may, need not be so.

Then you can weigh preconceived notions and imagination factors into the whole thing. But in any case, congratulations again on a nice find.:)

Technics SU7300:
Screenshot_2024-10-10_112104.jpg
 
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Damn £30 for one pristine Technics SU7300 it's just to congratulate. It is also stylish. :)

If it is possible to hear any difference between your amplifiers, I am guessing that it could perhaps be that the Technics SU7300 only has a damping factor of 20 (4 Ohm) that affects that. Maybe, but that is just a guess on my part. It also depends on which speakers you have.

Aiyima A07 max is load dependent which I guess Technics SU7300 is not. That, depending on the speaker, its load, can make them sound different. Note may, need not be so.

Then you can weigh preconceived notions and imagination factors into the whole thing. But in any case, congratulations again on a nice find.:)

Technics SU7300:
View attachment 397763
Thanks!
I tried various speakers, all decent but my Harbeths made it very clear that this amp competes well with modern kit. The clarity was superb. High volume is possibly it's weakness but we are talking ridiculous levels through my old RS6's that I never get close to.
 
I bought a pristine Technics SU7300 last week. Mainly because it was £30 but also because I remember having one before and thinking it was better than I'd expected.
So, taking things a bit more seriously this time, I've compared it to everything I currently have: Rega brio, Roksan K2, Cyrus 8xp and an Aiyima A07 max, amongst others.
This is an astonishingly good amplifier! It's clarity, soundstage, looks and sheer listening pleasure beat each of the above imo.
I'm a bit shocked as I've always thought of vintage mid end stuff as a bit of a novelty.

This is completely subjective and only based on listening tests but I'd say although both the Cyrus and Roksan are better at certain things (bass definition mainly) it's honestly not by an awful lot.

The aiyima in particular sounds dry and weedy now.

Sorry for the long post-just not sure where else I might get interesting feedback.

View attachment 397754

It is very nice to know that now you are in our/my league of rather classic (vintage?) HiFi integrated amplifiers!:D

I too use four HiFi integrated amplifiers even in my DSP-based multichannel multi-SP-driver multi-amplifier fully active audio setup (ref. here post #931 on my project thread for the latest setup) where I shared/emphasized pros and merits of HiFi integrated amplifiers in DSP-based audio system.
I wrote there #931 as follows;
Here in this post, please let me emphasize again about the pros and merits of relative gain (i.e. tone) control not only in digital domain but also in analog domain using pre-amplifiers or integrated-amplifiers (in my setup). I recently wrote again in my post #56 on a remote thread like these;
Yes, as for safe and flexible tone controls (or I can say "relative gain controls among the multiple SP drivers"), my stance (policy) at least, is that we are encouraged to utilize the "best combination" of "DSP configuration in digital domain" and "analog domain tone controls using HiFi-grade preamplifiers and/or integrated amplifiers".

We need to note (and to respect for) that analog domain tone controls (relative gain controls among the multiple SP drivers) give no effect nor influence at all on the upstream DSP configuration (XO/EQ/Gain/Phase/Polarity/Group-Delay). I believe that this is a great merit of flexible tone controls in analog domain. We know well, on the other hand, in case if we would like to do the "tone/gain controls" only within DSP configurations, such DSP gain controls always affect more-or-less on "XO" "EQ" "phase" and "delay" of the DSP settings which will leads you to possible endless DSP tuning spirals every time; within DSP configurations, XO EQ Gain Phase and Delay are always not independent with each other, but they are always interdependent/on-interaction.

Just for your possible reference, my DSP-based multichannel multi-SP-driver multi-amplifier active system has flexible and safe analog level on-the-fly relative gain controls (in addition to upstream on-the-fly DSP gain controls) for L&R subwoofers, woofers, midrange-squawkers, tweeters, and super-tweeters, all independently and remotely. My post here shows you a typical example case for such safe and flexible on-the-fly analog-level tone controls. This my post (as well as
this post) would be also of your interest.

Of course, I know well that I (we) can also perform such relative gain control using DAC8PRO’s 8-channel output gain controllers. I do not like, however, to change the DAC8PRO’s output levels frequently on-the-fly (while listening to music) due to safety and inconvenience concerns; I like to keep DAC8PRO’s analog out gain level always at constant -4 dB which should remain to be usually “untouchable” in my case.

One of the very unique aspects/features of my multichannel audio rig is that I fully utilize four HiFi-grade “integrated amplifiers” plus L&R active subwoofers, each of them have its own gain (volume) controller for safe and flexible relative gain (tone) control in analog domain even on-the-fly i.e. while listening to music.

You would please find inside and outside photos of the four integrated amplifiers I use, i.e. ACCUPHASE E-460, YAMAHA A-S3000, SONY TA-A1ES and YAMAHA A-S301, in my post #38 on this thread.

If you would be further interested, please visit my post here #311 for the summary of my amplifier selection exploration in my multichannel audio project.
 
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Thanks!
I tried various speakers, all decent but my Harbeths made it very clear that this amp competes well with modern kit. The clarity was superb. High volume is possibly it's weakness but we are talking ridiculous levels through my old RS6's that I never get close to.
Sounds like you have a nice experience. :)

Some general thoughts. I wonder if you can use the tape out , rec out:
Screenshot_2024-10-10_143130.jpg
..on a Technics SU7300 to send that signal to an active subwoofer? In that case, you must have a pre amp or DAC with volume control that is fed into the Technics SU7300 so that you can change the volume of the Technics SU7300 and the subwoofer at the same time.
That if Technics SU7300s tape out works for such a setup, that is.
That if you want subwoofers in your solution, but that's another question.:)

Given the Technics SU7300 damping factor, I would have probably let it power up 8 Ohm speakers. Then those with a sensitivity of at least 88 dB.
But with that said, 20 in damping factor at 4 Ohm if it affects the sound, FR? I don't know.

As the saying goes, if it ain't broke, don't fix it, I usually sign. Having said that, close to 50 years old, then maybe the amplifier would benefit from some electronic components being replaced? What speaks against it is as you said: pristine it may not have been used and worn so much over the years so then it is not needed.:)

Edit:
Speaking of damping factor, from another thread. Page 7, #140 and page 8, #141:

Amplifier Damping Factor.PNGScreenshot_2024-10-10_135407.jpg

 
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Sounds like you have a nice experience. :)

Some general thoughts. I wonder if you can use the tape out , rec out:
View attachment 397787
..on a Technics SU7300 to send that signal to an active subwoofer? In that case, you must have a pre amp or DAC with volume control that is fed into the Technics SU7300 so that you can change the volume of the Technics SU7300 and the subwoofer at the same time.
That if Technics SU7300s tape out works for such a setup, that is.
That if you want subwoofers in your solution, but that's another question.:)

Given the Technics SU7300 damping factor, I would have probably let it power up 8 Ohm speakers. Then those with a sensitivity of at least 88 dB.
But with that said, 20 in damping factor at 4 Ohm if it affects the sound, FR? I don't know.

As the saying goes, if it ain't broke, don't fix it, I usually sign. Having said that, close to 50 years old, then maybe the amplifier would benefit from some electronic components being replaced? What speaks against it is as you said: pristine it may not have been used and worn so much over the years so then it is not needed.:)

Edit:
Speaking of damping factor, from another thread. Page 7, #140 and page 8, #141:

View attachment 397778View attachment 397779

Yes, if the subwoofer has some means of level attenuation, and/or if one adds an in-line attenuator. The problem with TAPE OUT is it's at a fixed output level, independent of the volume control setting or any other preamp controls (ahem, e.g., tone controls). That said, if one controls level upstream of the little Technics integrated amp (e.g., the source component has some sort of adjustable attenuation, perhaps via a remote control) -- well, then, Bob's your uncle!
 
Yes, if the subwoofer has some means of level attenuation, and/or if one adds an in-line attenuator. The problem with TAPE OUT is it's at a fixed output level, independent of the volume control setting or any other preamp controls (ahem, e.g., tone controls). That said, if one controls level upstream of the little Technics integrated amp (e.g., the source component has some sort of adjustable attenuation, perhaps via a remote control) -- well, then, Bob's your uncle!
I think you may have overlooked part of the comment you quoted?

In that case, you must have a pre amp or DAC with volume control that is fed into the Technics SU7300 so that you can change the volume of the Technics SU7300 and the subwoofer at the same time.
 
I think you may have overlooked part of the comment you quoted?
I did indeed. Thanks/sorry!
A setup with Tape output to subwoofer is exactly what I did with my vintage HK330C.Trim the volume on the HK330C and on the amplifier in the subwoofer to match, then adjust the master volume via a Topping E30 DAC when listening to the music. It worked fine. :D

Pictures of that setup, as usual I take blurry pictures but you can see how I did it:
IMG_20230824_182323.jpgIMG_20230824_182327.jpgIMG_20230824_205111.jpg

There are nice and useful functions with some old vintage amplifiers and or receivers. :)
 
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Yes, tape loops can come in handy. :)
As do switchboxes of various forms. :cool:


Unfortunately, this handy and simple little Azden switchbox doesn't photograph well -- ahem, more to the point, I cannot photograph it well. :facepalm:
The little silver metal box to its left is a stereo TVC that also contains a three-position stereo source switch -- I am all about combinations and permutations (or, at least, enabling them). ;)

Fortunately, some to many modern components do have "processor loops" that offer a similar breakpoint.
 
Sansui AU-517 and AU-717

The 517 has been restored with all new caps and components where needed. The 717 is cleaned up and waiting it's turn. The 517 just sounds good, easy to listen to and plenty detailed. You don't NEED more, but...

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AU-717 is very similar

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It's better looking inside than outside IMO. Makes it hard to keep the cover on.
 
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