Audio Research D79A poweramp

[christoph]

Hi guys

I could buy a Audio Research D79A from someone rather close to my place but I have no clue about this beast.

Is it as good soundwise as the seller claims and how much would be a fair price if the unit is in very good condition?

How does this amp from yesteryear (when did it hit the market) compare to the similarly specced (75 watts) ARC Reference 75 from today?

Thanks in advance for your help.

 

[analyzer]

I remember very well to have listened with great pleasure to D-79A and especially the D-79C version here in my town.
It was usually paired with preamp SP6 and in one session I remember also to have seen for the first time to the SP-10 in two chassis. Speakers were the Magnepan family (MG-I / II and Tympany) and also Acoustat monitor (I don't remember the model exactly, it was without internal servo amp obviously).
Super midrange, good details, definition at its best ... for these years. You must consider that my experience dates in the early '80's and since then IMHO amplifiers have been ameliorated especially in tonal coerence, definition of the bass, quickness and ambience retrieval...
My personal opinion follow the rules normally adopted for purchase of a collector's piece. Well... buy it only if the unit is first of all in working order. A technical check is probably needed in order to be safe, and it will be not cheap, at least 500-1000 euros plus new tubes.
Furthermore... at least the faceplate must be near mint; last but not least are very welcomed the original box, manual and possibly a service history.
At the end price will be in my opinion decisive.
just my two cents
Marco

 

[microstrip]

It depends on so many factors that my humble advice is that if you need to ask you should not buy it . Sorry ...

Current condition, maintenance, partnering equipment, are you a real collector? All this factors must be weighted.
IMHO - and others will probable disagree - you need a SP8 or SP10 to properly drive these old ARC preamplifiers.

The D79 circuit is complex - most people servicing modern tube amplifiers will desperate with the cross coupled driver circuit!

 

[Kcin]

It depends on so many factors that my humble advice is that if you need to ask you should not buy it . Sorry ...

Current condition, maintenance, partnering equipment, are you a real collector? All this factors must be weighted.
IMHO - and others will probable disagree - you need a SP8 or SP10 to properly drive these old ARC preamplifiers.

The D79 circuit is complex - most people servicing modern tube amplifiers will desperate with the cross coupled driver circuit!

I remember very well this amp. I had a D79c really at this vintage if you are not technically adept or do not mind submitting an amp like this to a competent tech ( may be difficult in Europe that anyone has touched one ever) I would say stay away. It will need power supply work at the least and things get pretty toasty on those boards which can cause all sorts of other problems.

The period correct preamp is the SP 6 and maybe the SP8 and SP10 ( had those too) Its really not necessary to drive the amp with any SP ARC preamp.
The REF75 would be far more reliable maybe less costly in the end and most probably sound better.

I bought mine from a chap that drove Beveridge IIIs with his. Later sold it to a Magnepan user. Its a great big amp that sounded better as the 79b I think than the 79c.

A bit of an engineering marvel for the time. I would buy it if the price was right and it was cosmetically good and I would expect that I may spend a month fixing it. It actually is too big and heavy to play with- ok I talked myself out of it. I have enough projects!

 

[christoph]

Hello guys

I thank you all for your advice to be cautious.
I'm not a techie but I know a technician who repairs ARC gear.
I will also ask him about this D79A...

Judging the pictures, the amp looks flawless and the seller claims it looks very good and works perfectly.
All NOS tubes, no noise even directly on high sensitivity speakers.
The vents work silently and even the meters and the lamps behind the meters work

Now this all sounds too good to be true
But the seller is only 30 minutes away by car, so I could drive there and test this beast before I would commit

 

[morricab]

Hello guys

I thank you all for your advice to be cautious.
I'm not a techie but I know a technician who repairs ARC gear.
I will also ask him about this D79A...

Judging the pictures, the amp looks flawless and the seller claims it looks very good and works perfectly.
All NOS tubes, no noise even directly on high sensitivity speakers.
The vents work silently and even the meters and the lamps behind the meters work

Now this all sounds too good to be true
But the seller is only 30 minutes away by car, so I could drive there and test this beast before I would commit

I have heard that it is one of the best "classic" ARC amps. I heard one long ago in France on a pair of JBL C50 Olympus speakers. The overall sound was pretty colored but very lively. Not sure if the coloration was electronics or speakers...or both! Personally, I don't think it will beat anything you already own.

 

[christoph]

Hi Brad

I have heard that it is one of the best "classic" ARC amps. I heard one long ago in France on a pair of JBL C50 Olympus speakers. The overall sound was pretty colored but very lively. Not sure if the coloration was electronics or speakers...or both! Personally, I don't think it will beat anything you already own.

Thanks for your valued input.
I thought about pairing it with the Acoustats as a kind of vintage System...

 

[morricab]

Hi Brad



Thanks for your valued input.
I thought about pairing it with the Acoustats as a kind of vintage System...

My experience with PP tube amps on the Acoustats was mixed...they don't all like the load very much. Funny enough the SETs were happier and of course the Sphinx PJ14 likes the speaker very much .

 

[christoph]

My experience with PP tube amps on the Acoustats was mixed...they don't all like the load very much. Funny enough the SETs were happier and of course the Sphinx PJ14 likes the speaker very much .

The Lamms also work very well on the Acoustats

 

[morricab]

The Lamms also work very well on the Acoustats

I have no doubt...did you get them repaired?

 

[Golum]

The Lamms also work very well on the Acoustats

Well Karan was quite good also

 

[christoph]

Well Karan was quite good also

 

[christoph]

I have no doubt...did you get them repaired?

Yes, they are finally back home with Daddy again

 

[tdh888]

Hi guys

I could buy a Audio Research D79A from someone rather close to my place but I have no clue about this beast.

Is it as good soundwise as the seller claims and how much would be a fair price if the unit is in very good condition?

How does this amp from yesteryear (when did it hit the market) compare to the similarly specced (75 watts) ARC Reference 75 from today?

Thanks in advance for your help.

They’re quite good , mine are the D79B version , I still have a pair driving Magnepan MGA using the ARC EC21 electronic X over . I prefer to listen to it when partnered w/ my modern line & phonostage (ARC REF5SE & REF PHONO 2SE) rather than my ARC SP10 MK2. I plan to have the D79B’s recapped probably next year hopefully .

 

[gian60]

I bought D79A 4 years ago.
Was perfect and price euro 2.800
I had SP 3, SP 6,SP 8,SP10 , D 90 B and D 250 but never own D 79 that always i wanted,and 4 years ago i founded in a shop of a friend and i bought to put in my second system with Sentry III

I was sure sound was not very good,in comparison Kondo and Audiotekne i had,but the beauty of D 79 took me and i bought.
But when i connect to the system i was surprised of his quality,little colored like Morricab told,but big sound,full with power and dynamic,mid bass no bad and no roll off
Not a modern sound and better of yours amp,but good.

If price and amp are good i suggest to buy,to listen sometimes and to see him you will be satisfied

 

[microstrip]

I(...) I was sure sound was not very good,in comparison Kondo and Audiotekne i had,but the beauty of D 79 took me and i bought.
But when i connect to the system i was surprised of his quality,little colored like Morricab told,but big sound,full with power and dynamic,mid bass no bad and no roll off
Not a modern sound and better of yours amp,but good.

If price and amp are good i suggest to buy,to listen sometimes and to see him you will be satisfied

Although I am not a partisan of blind tests, for some types of gear, such as reel tape machines or the D79, IMHO we really need a blind test to listen critically. Reels and beautiful VU's are hypnotic!

 

[tdh888]

Sorry for the late update . I was able to compare my newly recapped D79B to a REF 75 . The REF 75 gave more musical information but it lacks meat in the bone in the mids were the D79B excels . The D79B is more powerful sounding and has a stronger bass . The mids characteristic is similar but the D79B has this less electronic signature . I enjoyed using both amps , but if your asking me if I’m going to sell my D79B to get a Ref 75 the answer is no .

 

[DonH50]

They’re quite good , mine are the D79B version , I still have a pair driving Magnepan MGA using the ARC EC21 electronic X over . I prefer to listen to it when partnered w/ my modern line & phonostage (ARC REF5SE & REF PHONO 2SE) rather than my ARC SP10 MK2. I plan to have the D79B’s recapped probably next year hopefully . View attachment 42157

Small world. For many years my MG-IIIa's were driven by a D79, sometimes also using an EC21 or various other crossovers with a Counterpoint 220 as the bass amp.