• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

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

Hipocrates

Member
Joined
Dec 31, 2018
Messages
30
Likes
23
Location
Costa Rica
What speakers do you recommend?
My experience with it is, the Usher 6391, be716, Kef R300, Polk LsiM703, Large Advent, JBL 4312, 4333A, B&W 602 and it make them sound a their best... My point is, that a proper reconditioned 2385 will do well with top quality speakers... The JBL 4311 and 12 are not my favorites speakers, but they do ok and some people really like them. So maybe they will work for you.

Look for the best speaker for your needs(size, budget, sound, aesthetics ) and the unit will perform extremely well. Remember that speakers opinions are like bellybutons (every one has one). Something like the usher audio be716 or those newer bookshelf speakers reviewed here (revel, purifi for example) will do great IMHO.
 

DSJR

Major Contributor
Joined
Jan 27, 2020
Messages
1,830
Likes
2,331
Location
Suffolk Coastal, UK
I've been using my 405-II with a pair of Klipsch Fortes in a vintage system and I guess not needing so much juice to power them the Quad is in its element, I sometimes swap the Klipsch around with a pair of less sensitive Dynaco A25-II with equally acceptable results though, it might be a synergy thing going on with older kit but the 405-II just sounds right to my aging ears.
I've owned two 405-2's in my time, both freshly updated to mk2 spec with new supply caps (originals in both were leaking after eleven years or so) and two new boards. the speaker nip-on terminals were replaced and RCA's fitted with allowances for amp 'grounding.' The 'clamp' boards were also dispensed with as this little circuit went over to the mk2 power amp boards.

Both amps 'sounded' just fine but current output was still rather low and into my ATC 20's, the second one could fry eggs (I wasn't really thrashing it officer... - gulp). Both amps idles cool enough. Into Klipsch, the thing would be barely ticking over for a high volume level.

Into the ATC's, I replaced the seconf 405-2 with a pair of AVI S2000 Monos rated at 140W each and subjectively, they went as loud (only a couple of dB on paper louder) and ran barely warm even wit my music pumping through them, so I was a happy bunny. A year later, the 100A's came along and I was in music heaven until they had to go and be replaced by a different kind of heaven and possible hell :D
 

DSJR

Major Contributor
Joined
Jan 27, 2020
Messages
1,830
Likes
2,331
Location
Suffolk Coastal, UK
I would be fascinated to see how arguably the first Class-A amp available in the UK the Sugden A21 (wooden case) would perform under modern testing techniques. I love the sound the 50+ year old Sugden produces with my old mkII Klipsch Fortes whereas most of the pricier modern kit does not cut the mustard and I have always wondered how it would test.
Maybe it was old, but I bought our loan A21 just like the one in your pic. It actually sounded bright and thin with noine of the clogged-up bloat-warmth of it's replacement from decades later (I'd LOVE to know how this latter one measures as it's so obviously coloured in the way the Musical fidelity A1 'griddle' was...)
 

Mnyb

Major Contributor
Forum Donor
Joined
Aug 14, 2019
Messages
1,504
Likes
1,988
Location
Sweden, Västerås
Maybe it was old, but I bought our loan A21 just like the one in your pic. It actually sounded bright and thin with noine of the clogged-up bloat-warmth of it's replacement from decades later (I'd LOVE to know how this latter one measures as it's so obviously coloured in the way the Musical fidelity A1 'griddle' was...)

Som one measured the A1 .

Btw did not the old MF amps even had crossover distorsion like it was 1960 all again ? they redemed later by buildings some stuff with decent performance
 

DSJR

Major Contributor
Joined
Jan 27, 2020
Messages
1,830
Likes
2,331
Location
Suffolk Coastal, UK

Som one measured the A1 .

Btw did not the old MF amps even had crossover distorsion like it was 1960 all again ? they redemed later by buildings some stuff with decent performance
I'm singling out the very soft toned A1 and a better toned but hideously distorted A100 (-30's dB I remember) and this latter thing STILL got a 'recommended' rating.. The A100 had a fan inside which kind of blew air around the interior. We took a look at the period B&O Beomaster 6500 (part of their flash 'stack system') which had a little soundless fan and a properly moulded duct to direct the air where it was needed. I didn't really fully appreciate this kind of design care back then, but I do now ;)
 

Scytales

Member
Joined
Jan 17, 2020
Messages
23
Likes
24
Location
France
I was able to get a Yamaha B-2X and the C-2X



The specs are really good for both pieces, is there anything out there better in term of specs ?
I have one C-2x. It's an excellent preamplifier. A French repairer made some measurements on another one with modern devices : https://www.audiovintage.fr/2021/12/13/yamaha-c-2x/

I also personally made some noise measurements on mine :

bruit-c-2x-2.jpg
 
Last edited:

NTTY

Member
Forum Donor
Joined
Apr 27, 2018
Messages
14
Likes
19
I'm gonna throw a curve ball. Got a soft spot for aiwa stuff growing up with their tape players. This is the best amp they ever made, last time one came up on ebay I got out bid in the last couple of seconds. Not sota but I still want one.View attachment 70134
I sent one of mine to the french restorer mentioned earlier.

Details here: https://www.audiovintage.fr/2022/07/07/aiwa-aa-8700/

I asked for additional measurements as well (not published), including amplifier and preamp separately. The amp measures significantly better than the preamp. Decent phono section though (MM and MC).

The amp shows 0.006% DHT maximum from roughly 0.1W to 78W RMS, and up to -120dB(A) S/N.

Max power is 2x82W RMS (8 ohms @ 0.05% DHT). When letting it go to 1%, we get 2x90W.

This was the first and last tentative from Aiwa to go high end. The inside shows good intention and not so good implementation. Too bad they did not continue.

It sounds flawlessly IMHO even when I challenge it with modern or older high performers pure power amplifiers.

And good looking :)

AA8700-004.jpg


Cheers
 
Last edited:

Thomas_A

Major Contributor
Forum Donor
Joined
Jun 20, 2019
Messages
1,978
Likes
1,376
Location
Sweden
OP
restorer-john

restorer-john

Master Contributor
Joined
Mar 1, 2018
Messages
9,610
Likes
27,332
Location
Gold Coast, Queensland, Australia
I sent one of mine to the french restorer mentioned earlier.

Details here: https://www.audiovintage.fr/2022/07/07/aiwa-aa-8700/

I asked for additional measurements as well (not published), including amplifier and preamp separately. The amp measures significantly better than the preamp. Decent phono section though (MM and MC).

The amp shows 0.006% DHT maximum from roughly 0.1W to 78W RMS, and up to -120dB(A) S/N.

Max power is 2x82W RMS (8 ohms @ 0.05% DHT). When letting it go to 1%, we get 2x90W.

This was the first and last tentative from Aiwa to go high end. The inside shows good intention and not so good implementation. Too bad they did not continue.

It sounds flawlessly IMHO even when I challenge it with modern or older high performers pure power amplifiers.

And good looking :)

View attachment 217086

Cheers

I have the matching tuner for that. The FM AT-9700. It weighs more than most amplifiers.
 
OP
restorer-john

restorer-john

Master Contributor
Joined
Mar 1, 2018
Messages
9,610
Likes
27,332
Location
Gold Coast, Queensland, Australia
any comments ?
Have you ever work in one

@restorer-john ?​


It's a great amplifier and extremely reliable. The only units I have ever seen, had bulged caps from slight overvoltage here in Australia.

Brown bond glue corrosion issues are also something to deal with from Yamaha at that time. Nothing too serious. Have a good look for it when you get the unit.

$100 is an insane bargain.
 

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
13,682
Likes
13,476
Location
Canada
It's a great amplifier and extremely reliable. The only units I have ever seen, had bulged caps from slight overvoltage here in Australia.

Brown bond glue corrosion issues are also something to deal with from Yamaha at that time. Nothing too serious. Have a good look for it when you get the unit.

$100 is an insane bargain.
This is the originator of the M85 red display that everybody got horned up on when in the stores? Awesome display. :D
 
OP
restorer-john

restorer-john

Master Contributor
Joined
Mar 1, 2018
Messages
9,610
Likes
27,332
Location
Gold Coast, Queensland, Australia
This is the originator of the M85 red display that everybody got horned up on when in the stores? Awesome display.

Yep. To me, those red bars looked like some nuclear powerstation meter from a James Bond movie.

I've got an MX-600/CX-600 in my collection.
 

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
13,682
Likes
13,476
Location
Canada
Those where limited quantity in Canada. We got some, we sold some and we got no more....lol. We always had access to M85s though. For years we had access to M85s. I think Yamaha Canada ordered in too many.
 

G|force

Active Member
Forum Donor
Joined
Apr 8, 2021
Messages
210
Likes
227
Location
Gualala, CA
This was probably discussed up thread, but I can't select a vintage amplifier to compete with a modern one without specifying delivered power of said amplifier(s). Are we talking 20W, 100W, >200W? No matter, I would't use a vintage amplifier unless I had to.
Regarding Crown D-75, yes old ones can be mechanically noisy if 'ridden hard and put to bed wet' but some early examples are silent, it all depends. The transformer windings buzzing at 60 or 50 cycles is of course the source of such noise, and some have gotten loose, some remain tight.
*magnetostrsiction*

Regarding Yamaha M-85, It was a formidable amplifier in it's day, as were a lot of the Yamaha 'natural sound' products. I still have a T-80 tuner.

Make a saved search on eBay for an M-85 over some months in USA and you can see what sellers ask for 'working' and 'not tested' examples. Not worth the shipping today IMO, same goes for Luxman Sansui Pioneer Technics/Panasonic etc.
I'd choose smaller lighter cheaper with higher performance and a warranty.

It's not a numbers matching Hemi Cuda. :)
 
Last edited:

Holmz

Major Contributor
Joined
Oct 3, 2021
Messages
1,283
Likes
759
Location
Australia
This was probably discussed up thread, but I can't select a vintage amplifier to compete with a modern one without specifying delivered power of said amplifier(s). Are we talking 20W, 100W, >200W? No matter, I would't use a vintage amplifier unless I had to.

It depends on the speakers.
I don’t think I would be using an 8 ohm amp on new 4 ohm speakers, but 8 ohms speakers should be fine.
 

G|force

Active Member
Forum Donor
Joined
Apr 8, 2021
Messages
210
Likes
227
Location
Gualala, CA
It depends on the speakers.
I don’t think I would be using an 8 ohm amp on new 4 ohm speakers, but 8 ohms speakers should be fine.
Which 4 Ohm speakers?
What is an 8 Ohm amp?

So by your way of reasoning, an amp rated to deliver 80, 100, 150W into 8 Ohms would be "sketchy" delivering 50W into a 4 Ohm load? Alright.
 

dlaloum

Major Contributor
Joined
Oct 4, 2021
Messages
1,373
Likes
886
Which 4 Ohm speakers?
What is an 8 Ohm amp?

So by your way of reasoning, an amp rated to deliver 80, 100, 150W into 8 Ohms would be "sketchy" delivering 50W into a 4 Ohm load? Alright.
Typically most 8ohm rated amps will handle 4 ohm OK

But 3ohm, and 2ohm.... are a whole different ball of wax.

And speakers "rated" at 4 ohm typically have points on their frequency/impedance at which they drop down well below 4ohm (in the case of my own speakers 3ohm in the bass and 1.6 ohm up at the tweeter).

But it is frequently hard to tell what an amps capabilities are outside of the 8ohm to 4ohm range, as most manufacturers provide no information as to low impedance speaker ratings for their amp. ( a nice alternative would be current capability for the amp, which is usually a good indicator of low impedance load capabilities)

Like I have stated elsewhere - this is the spec chart I would want to see for any power amp:

Quad 606 power output.jpg

This is the specification for a Quad 606 vintage power amp "Brick".
It drives 8ohm and 4 ohm speakers very well indeed
2 ohm speakers it is mostly OK but not great - the current limitations constrain it severely
1 ohm it runs out of puff...

All of which can be quickly and easily determined from this specification graph!

The spec also states "unconditionally stable at any load" - and unlike many current and past amps it doesn't shut down, go into a protection mode, or release its magic smoke, when handling difficult loads.
 
OP
restorer-john

restorer-john

Master Contributor
Joined
Mar 1, 2018
Messages
9,610
Likes
27,332
Location
Gold Coast, Queensland, Australia
Which 4 Ohm speakers?
What is an 8 Ohm amp?

So by your way of reasoning, an amp rated to deliver 80, 100, 150W into 8 Ohms would be "sketchy" delivering 50W into a 4 Ohm load? Alright.

You're missing his point, albeit one not made clearly by @Holmz

I could go into the details of amplifiers, tradtitional nominal impedances and over agressive current limiting in high powered designs in the 1970s, but suffice it to say, expecting amplifiers designed and sold in the 1970s to deliver ever increasing (or so-called doubling down) power as the load impedance decreases is not what they were designed to do. It certainly doesn't make them inferior to designs that advertise such.

That said, there are still plenty of vintage amplifiers that are worth the money to acquire, ship and enjoy. There's very little of the current crop of products, from any manufacturer that are built the way I find exciting, letalone worth what they are asking.
 
Last edited:
Top Bottom