What Audio Research power amps have you owned or admired?

[DaveyF]

Thanks for that mep and DonH50. I asked my tech again about this issue. He seems pretty sure that the caps are good in my ARC and that in general caps are replaced far more often than they need to be.
I think that one of the problems in general about older equipment is that it is prone to failure due to any number of different issues based on age.(kind of like us too!) I suppose one could replace all the caps and tubes and possibly
even resistors and then expect a more robust life. OTOH, I have had tube amps that were fairly new and had caps blow and tubes arc etc. I think that this may be one of the problems with an amp or any piece
of equipment that gives off a lot of heat. I do agree totally with DonH50's last sentence though.
BTW, mep, surely the life of the cap has to do with the amount of time that the unit is up and running. Would not an amp that runs 24/7 typically have a lower life on the caps than one that has been used infrequently over many years?
You say elecrtolytic caps are spec'd for a 20 year life; surely that must somehow correspond to the amount of use that the amp has seen? ( the more use, the lower the life, the less use the longer the life) The type of climate and care that the amp has been used in also might have a bearing on the life of the parts.There are guitar amps on the market and being used right now, that are over 50+ years old that are still highly prized due to the fact that they have their original caps and basic parts/speakers etc, are you saying that all of these amps are likely to self-destruct due to their age? I am just wondering?

 

[mep]

Davey-Ask any guitar amp tech how many vintage amps still have their original PS cap (usually a multi-section can) and work correctly. The power supply caps and the coupling caps are usually the first thing that starts causing problems in these old amps besides the selienium rectifiers used for the bias supply. There are people who are museum amp collectors and they insist that an amp be all original. That is fine as long as you don't turn it on and play through it. Then there are the real musicians that use the amps and they want the orginal tone, but they need them to be reliable as well. My Ampex 350s which have outboard tube power supplies have sockets for the filter capacitors which makes changing them out a breeze. I don't know why Ampex would have done that if they didn't intend to make replacement easy because they knew these pieces would be around a long time and the filter caps would need to be changed. Filter caps are like a timing belt on an engine. It's not a question of if they will break, it's a question of when. You can cross you fingers and hope your timing belt never breaks and drops your valves on to your pistons or you can do preventative maintenance and save yourself a bunch of money.

 

[DaveyF]

mep, I agree that's a good analogy. However, I think that a car that is 40 years old and has only done 5000 miles since new probably doesn't need to have the timing chain replaced. Same applies to an amp, IMHO just because an amp is a certain age doesn't mean it has had much use. So, I think what my tech is saying, is that age isn't the main determinant as to the condition of the caps. To replace perfectly good caps ( which he says is done way too frequently) isn't in the best interest of anybody except the company doing the work.

 

[DonH50]

While not a fully consistent analogy, both rubber belts in cars and capacitor dielectrics dry out and crack over time and need to be replaced even if they just sit there unpowered. However, if you have had them checked and they are OK, play on!

 

[mep]

mep, I agree that's a good analogy. However, I think that a car that is 40 years old and has only done 5000 miles since new probably doesn't need to have the timing chain replaced. Same applies to an amp, IMHO just because an amp is a certain age doesn't mean it has had much use. So, I think what my tech is saying, is that age isn't the main determinant as to the condition of the caps. To replace perfectly good caps ( which he says is done way too frequently) isn't in the best interest of anybody except the company doing the work.

As Don just stated, rubber belts will change over time and not in a good way whether you use them or not. Tires are the same way which is why manufacturers are required to date their tires and they are not supposed to be sold if they are over so many years old (and I don't remember the number of years before they are considered dangerous). The bottom line in your case is that if you had a good tech check your caps and he gave them a clean bill of health-rock on. If you have a car that you don't hardly drive and you think you don't have to change the timing belt for 20 years-good luck. I have a 2006 Passat with the 3.6L engine that only has around 24K miles on it. I will be changing out the timing belt before 60K miles because the belt will be old long before it ever sees the recommended mileage and I don't want to risk ruining an engine. The bottom line is that your thinking that if you don't use something it will last longer, but that doesn't apply to all materials.

 

[DaveyF]

Mep, don't get me wrong, I agree with you that as things age they deteriorate. This is true whether the item is used or not. In regards to engines, I also agree that it is prudent to change timing belts etc. way before they need to be changed or are even showing signs of wear.
However, I do think that a timing chain ( NOT rubber belt) that has not seen much use may not need to be changed until such time as the chain has seen the usage suggested by the manufacturer as a recommended change time. My main point is simply that with some things that aren't
exhibiting much wear, it isn't always necessary to replace them just because they are old. In my case, my tech assures me that my caps are fine. He also says it is common in the industry that caps are replaced before they need to be. Obviously, if a cap is too old it has a higher chance of
failure and that there are many instances when caps have failed due to age. BTW, the generally accepted age limit on tires before they are considered dangerous is seven years, regardless of condition; But tires aren't caps.

 

[mep]

The tire comparison was just to show you that even if something isn't used at all it can turn to crap and be unsafe and you were starting to make me think that you had convinced yourself that if something is not used or barely used it will last forever. I think we are fairly close in agreement now.

 

[tdh888]

ARC has a 40 year history of making power amps. In particular, some of the tube models have been iconic products that are still interesting decades later. When I look at an old D-79 I just shake my head -- it is a massive industrial-looking product that looks like it could get a second job as an arc welder. But it only puts out about 60 watts per channel. The D-79 represents an overkill approach that is entertaining just to look at.

http://www.arcdb.ws/D79/D79.html

I have a D-70 II from the 1980s with the same power output. It has considerably fewer parts than the D-79 but still works perfectly. The only issue is that the bias setting procedure may be the least friendly of any tube amp.

http://www.arcdb.ws/D70/D70.html


What ARC amps have you owned and what are your favorite ones?

Hi Jay S,

I still own a couple of ARC Amps (a pair of D79B's,D250mk2 servo,Classic 150 monoblocks)and my favorite is the D79B ,it was love at 1st site when I saw this amp 24yrs ago.Maybe its the best medium powered amp ARC built.Its Overbuilt,overkill ( 550 joules storage energy for a 75w/ch amp same energy storage as their monster amp of that time the D250),super expensive when it was new ( $4500 back in 1981).Bias is a breeze, the adjustment can be made from the faceplates using the Vu meter as your guide(same as the Ref 300/600).DC balance can be set by the owner if you know how to use a digital tester,its done from the back( just remove the rear cover) w/ clearly defined test points.It has 3 cooling fans inside for cool operation and a Power Meter aside from the Vu to monitor incoming AC voltage. ARC said they cant make amps like this anymore because its going to be very expensive to build/and sell.Downside of ownership is the price of replacing the filter capacitors it has 21 of these and the price is $50 ea W/ adoptor so you can use the orig.circuitboard were its mounted or you can get it directly from NTE for about $38ea w/ out the adoptor.
The ARC amps that I admire (heard) and hopefully own them someday and add to my stable are the REF 600 and the REF 610.

 

[Steve Williams]

I owned the Ref 600 Mk lll with a Ref 3 preamp several years ago. Phenomenal sound but unless you live in a cool climate those amps have 62 tubes so be prepared to sweat

 

[Jay_S]

Downside of ownership is the price of replacing the filter capacitors it has 21 of these and the price is $50 ea W/ adoptor so you can use the orig.circuitboard were its mounted or you can get it directly from NTE for about $38ea w/ out the adoptor.

There is another WBF member who owns a D79B. The capacitors definitely need to be replaced. Sounds like a $1,000 plus job but probably worth it.

 

[tdh888]

I owned the Ref 600 Mk lll with a Ref 3 preamp several years ago. Phenomenal sound but unless you live in a cool climate those amps have 62 tubes so be prepared to sweat

I envy you Steve Williams for having the chance to have owned the REF 600. In our country its so hot that its mandatory that we have airconditoners in our listening rooms.

thanks for your reply,

tdh888

 

[tdh888]

There is another WBF member who owns a D79B. The capacitors definitely need to be replaced. Sounds like a $1,000 plus job but probably worth it.

When I went to the ARC factory last 2007 they told If I wanted my Amps reconditioned by them. If Im not mistaken they offered $1800 for the D79B (cap replacement is inclusive) servicing.(all parts are replaced except for the tubes, transformers, circuit board)It was kind of tempting, (bec if I sold my amp and add $1800 were will I get a replacement amp that will be as good/better than the D79B) but the price to ship my amp from our country to Minnesota is going to be prohibitive. Now Im thinking of just buying all the parts from ARC and ask local tech to replace/install them.

tdh888

 

[Lee]

Admire my VT-100, dream of Ref 110.

 

[jadis]

3 weeks ago, I upgraded my 2004 ARC VS110 to a brand new 2008 model VS 115. From 100 watts to 120 watts. I figure this might help my hungry Maggies.

 

[mep]

Let us know how that works out. 120 watts vice 100 watts really isn't much to talk about. Your hunrgy Maggies want current and not just watts. SS is what Maggies really crave.

And by the way, I have owned the following ARC amps: D-76, D-76A, D-79A, D-70 MKII, and the VT-100 MKII.

 

[jadis]

Let us know how that works out. 120 watts vice 100 watts really isn't much to talk about. Your hunrgy Maggies want current and not just watts. SS is what Maggies really crave.

And by the way, I have owned the following ARC amps: D-76, D-76A, D-79A, D-70 MKII, and the VT-100 MKII.

Yeah, 20 watts more isn't really much, but my priority was to update the entire amp to a more present one, which ARC said mimics its Ref series but for a lower price. And yes, one of the best amps I heard that can rock the Maggies was a Krell KSA 250 at showroom conditions.

 

[karma]

HI All,
Boy, what a bunch of ARC lovers here. Me too.

Over the years I have owned the SP-8Mk II, SP-10 Mk II, And the SP-11 Mk II preamp's.

On the power amp side I've owned the D115 Mk II and the D250 Mk II Servo.

My favorites? The SP-11 and the D250 by far. I still have both of them. The sheer power of the D250 gives a sense of ease when driving my difficult Martin Logan CLS IIA's that has to be heard to be believed. Do understand, my speakers are biamped and sub woofed so the D250 does no low bass work. But the few times I have run the stats full range, the bass was beautiful, just not deep. It's the nature of the stat panels.

I suppose I should, out of respect, mention my Mark Levinson NO. 23 power amp that powers my subs. It's a terrific solid state amp with a ton of power. It is fully capable of causing the lights to flicker with the right bass material. It's a little scary.

Speaking about bias, the D250 is easy though you still have to remove the cover. I just keep the screws removed so I can easily lift the cover off. The test points and the pots are very easy to get to and don't threaten your fingers with white hot heat. Of course, there are 16 measurement and adjustments that must be made, one for each output tube.

The D250 has four relatively quiet fans so it runs cool. However, the fans are louder than dead quiet so my amp is installed in a closet with its own air conditioner. This amp has been dead reliable as has the preamp.

I far prefer the SP-11 to the other ARC preamps I've had. It has the amazing quality of simply not being there. If you prefer a romantic presentation, then the SP-10 is the way to go. But, in truth, the SP-11 is far more neutral and transparent. The SP-11 seems to be very easy on tubes. I've had the original set of Bugle Boy tubes I installed for almost 20 years and they are still going strong. I think that is pretty good.

You guy's can say all you want about the other D series amps but the D250 is at another level of excellence.

Sparky

 

[Steve Williams]

am I the only one to have owned the Ref600 Mk lll

 

[mep]

am I the only one to have owned the Ref600 Mk lll

Probably. You've got all the cashish.

 

[Steve Williams]

It was an amazing amp

Only problem was the heat the tubes put out . I had to put in a dedicated central AC for my listening room