Old SS amps

@devinplombier 

Fascinating your knowledge on this.

So basically the older wine bottles I opened a few months ago, all bad and disturbing, are foreshadowing problems I may have connecting some pieces of equipment I haven't used for years. 

I’ve just finished restoring/tuning a Yamaha Pc5002m, better than spec and 8.5 looking. I’ve two driving the music section and a Pc4002m on the movie section. Certainly I’ve head room, no strain for anyone. The 5002m’s are truly audiophile be it in PA clothing, a marketing decision a.k.a. 101m reface. All three have had very time consuming and detailed refurbishing. Not a lot of technicians can or are willing to work on these, the detail justifies their spec sheet. Old to some, boat anchors to others, missing the bells and whistles of modern…time spent (hobby) irrelevant, its  about the sound quality. The make doesn’t matter if it’s liked and breaks ya fix it new or old. 
 

Cheers 

Often manufacturers would glue caps to the PCB. Although you'd like to think they did this for the sake of microphonics, the glue was there to hold the components in place while they were being soldered.

Sometimes with age and heat that glue kind of decomposes and spreads out over the PCB from under the cap. For all the world it looks like the cap is leaking, but it's not, it's just glue. 

Not that glue is necessarily benign: in rare cases it becomes conductive and causes short-circuits.

Old to some, boat anchors to others, missing the bells and whistles of modern…time spent (hobby) irrelevant, its about the sound quality. The make doesn’t matter if it’s liked and breaks ya fix it new or old.

@1971gto455ho 

+1 That's exactly how I look at it. Giving great gear a new lease on life is worth the while in my opinion. Congrats on refurbishing your PC5002M, these are gorgeous amps!

@emergingsoul sadly there is no variac for wine! 😁

I am 'Tipping my Hat' to those giving a Boost to and Promotion of the environmental considerate Circular Economy.

Land Fills need not be the Journey's End.

I know many who are Participant and unknowing, I am a knowing Participant and am Proud of the collective Walk the Walk being done.

Around the mid ’80’s Bob Carver made some very good sounding amplifiers with an unusual and very light power supply. He challenged critics to hear any difference between his M1.0 and an expensive high-end tube amp (forgot which one) - and he proved his point- they couldn’t hear a difference.
Subsequent designs like the PM1.5t and PM2.0t were made for the pro audio industry and they were immediately accepted for their light weight and superb audio quality - and now you can find these used on eBay for around $500. 
I don’t think anything these days at any price will give you better performance than these vintage Carvers- even at at ten times the price.

Only down side: A little bit of fan noise, but in a home system where these will be barely whispering, you can easily disconnect the fan, like I did with mine, running the woofers in a bi-amped system.
 

Marc Stager
and check out my cables:
https://silversolids.com/

Might not have all the numbers straight but

I like the 74ish Marantz 2035. 2135?  Cat Steven's,!  

I didn't like Sansui, Kenwood, Pioneer but could be mixed up.

Magnapans were too much for Ampzilla, Quattre.  I believe we settled on SAE.

We had Carvers and Leaches. Nice sounding amps.  The leach was reliable, Carver no.  

I still use an 8002 Aragon solid state dual monaural for my power amp. It is clear as a bell and puts out 400 watts into 4 ohms and is about 30 years old. Bought it new and have never been disappointed.

@bdp24: I have all three! My Bedini 25/25 still doesn’t work despite being sent to John Bedini (RIP) in Idaho three times. The Brown Electronics Lab (BEL) 1001 amp worked briefly after I acquired it from the original owner. He was a friend of Richard Brown (RIP). It is the first production one - serial no. 0001. The John Iverson (RIP) Electron Kinetics Eagle 2A is still working. All three are competitive sonically with today's six-figure made-in-Switzerland amps!

I have 3 old Yamaha AVRs.  One is 29 years old, another is 25 and the third is 21.  They all still work.  Amps last forever as long as the on/off switch works in my experience.  I bought the newest one used for $25 at a yard sale.  A great deal.  

My Classé Audio DR-9 amps are over 35 yrs. old and functioning fine.  They came with a lifetime warranty.  Try to get one of those these days.  I expect they were built to last.  They are Class AB, so never get as hot as Class A amps, so that also helps with their longevity.  I use them in bridged mode, so they provide loads of power and current.

About a year ago I removed the lids to remove dust, and I think I inspected the caps and didn't see anything suspicious.

+1 for McCormack.

Have a 225 if you're interested..

@drmuso 

Thumbs up from a fellow Classé owner! The David Reich designs were fantastic. I definitely have a pair of DR-3 VHC on my bucket list. 

Happy listening!

You need recapping if you turn the unit on, there is a flash of flame and the room fills with smoke. I found it (enormous, heavy, Adcom receiver) in a thrift store for $30. For $80 in parts (power supply capacitors) and a bit of work it now sounds wonderful. It's built like a tank! I'm still hunting for bargains but will wear goggles and a mask when powering them up for the first time. Perhaps I can find one of those flame proof suits Nascar drivers wear. That $12 Yamaha tape deck didn''t blow up, but it didn't play tapes ether.

@boomerbillone 

What you need is a dim bulb tester, not a gas mask 😂

In 1979, I purchased a McIntosh MC2120 power amp for $800, if I recall correctly, from which I graduated to Odyssey monobloc amps in early 2024.  The 2120 was in use the entire 45 years, less one month in the early 2000s for a refurb, which included an LED, capacitors, and other minor parts replacements, which cost me about half of the original purchase price.  The amplifier performed superbly, and I upgraded because I realized that I would better sound with more power for the speakers, and I actually considered seeking another MC2120 to bi-amp the speakers, but I was convinced to purchase more powerful monobloc amps.  With appropriate care, SS amps can serve a long time quite well. 

Many older power amps are still excellent - check them out and have them recapped if they need it. I still run small production Class A amps like the Belles A, a pair of bridged Classe DR3 VHC, a stereo Classe DR3, a Jeff Rowland 5, and a Robertson  4010 in various systems,

@jasonbourne71:

My Eagle 2 still works (and sounds) fine. I sold my Bedini 25/25 when it needed it's transformers replaced. I paired it only with QUAD 57 ESL's.

I never had a BEL 1001, but still have a PS Audio 200C, which I use with the bass panels of my Magneplanar Tympani T-IVa speakers. I guess I could have included the PS Audio amp in my list, but I don't know how it rates when compared with the others (I haven''t heard it in a while).

@bdp24 Was the Tympani Bass Panels used in Conjunction with the 57's?

I'm assuming in recent times the Bass Panels from a 25ish Year Old Speaker to augment a 65ish Year Old Speakers Bass.

 The Circular Economy is thriving.

If Yes to my assumption, I would like it if you would be willing to share more.

@pindac: No but using Tympani bass panels with Quads is a very interesting idea! The problem for me would be the required room size; the two Tympani bass panels are about 40 inches wide, the Quads about 34". Side-by-side the Tympani/Quad pairing requires just over 6 feet per channel! That 12 feet (for both channels) plus say 8 feet between left and right speakers requires 20 feet, and that’s with the Tympani/Quad pairing being right against the side walls. 

In the 90’s I put my Quads on top of ESS Transtatics, the Transtatics laid on their sides (20" tall when so placed). I used the Transtatics as subs; they feature a transmissionline-loaded KEF B139 woofer (Dave Wilson used a pair of that woofer in each of his original 1970’s WAMM super speaker).

In the 80’s and 90’s the Finnish company Gradient offered dipole/open baffle subs designed specifically for both Quad 57’s and 63’s. Those subs also served as bases for their respective speakers. The dipole/open baffle sub now offered by GR Research and Rythmik Audio is a much improved version of the ob/dipole design, and work splendidly with all dipole/panel speakers, including of course Quads. My Quads are now in storage, as I am currently listening to Eminent Technology LFT-8b’s and LFT-4’s. The GRR/Rythmik OB/Dipole Sub may be used in place of the LFT-8b’s stock 8" sealed woofer; the LFT planar-magnetic driver plays down to 180Hz (crossing over to the 8" dynamic woofer), and while "normal" subs can typically play no higher than 100-120Hz, the GRR/Rythmik OB/Dipole woofer can be used up to 300Hz.

I bought my Quad 303 new in 1978. It was still sounding great when I had it serviced by Quad in 2021. My Sumo Polaris II was untouched and working beautifully when I sold it in 2023, at 28 years old. I bought a recapped Mark Levinson 331 in 2020 - zero problems, and sold it for a profit last year. My star SS amps are my Michell Alecto II monoblocs, serviced by their designer in 2019 and still sounding fantastic at 30.

So I’ve had precisely zero problems with old SS amps over many years. As base class A/AB technology is pretty mature, they’re a good buy, and are a good way to experience different design philosophies and circuit topologies.

@bdp24 Thank You for the reply.

I asked about the IV Bass Panel as their are reports to be found of it used as a Bass Extension.

My 57's are Stacked, and I will one day produce a Ripole Bass to be coupled to them. This design has a Figure if Eight Radiation that has similarities to the 57 Radiation.

To date, but not with 57's all ESL Speakers heard with a Bass augmentation from a Typical Driver has been noticeable for the add on. This is not saying not liked, but noticeable is a distraction. The Ripole description commonly suggest the Bass Source is lost in the space and not detectable. That is the same description I can add for the 57's, hence the attraction to the design.

Many many years past I was demo'd at a Commercial Audio Event a Gradient Dipole with ESL 63's, I don't remember being that impressed, maybe the price at the time to feel the need to pursue the set up.

The most impressive / indelible demonstration and my Benchmark is the Tim De Paravicini 57''s directly coupled to Valve Power Amp's, his demo' room was non emptying, the experience changed my interest in End Sound for life. I have a close mimic version of this End Sound able to be produced today in my own system.   

Usually when I want substantially noticeable bass presence, I bring in the Cabinet Speakers to be hooked up and give them a run for a period of time.

I am not monogamous about End Sound or Orientated to one formed sound only. , This does not cause any concerns, being able to have variances in the flavour of the Sound acle to be produced, there are other Upstream devices at hand to do similar for the Speakers Types when in use.  

People often have their amps recapped unnecessarily. Many amps can go 40+ years before a capacitor goes bad. 

More often, in class A and A/B amps, the bias drifts. 

Outside of Class D and THX AAA designs, amp technology really hasn’t improved much in the last 35 years. Buying a flagship amp that is 20 years old but in great condition is a good way to get top-shelf performance for reasonable money, even if you do have to spend $1K to have it refurbished. 

I don't have the high end stuff that's dominating this discussion, but I recently got my Denon PMA 547 up and running. I bought the amp new in 1987 and shelved it in the early 2000s for an Adcom set up since sold. Took the Denon in and basically just cleaned things up and  it works perfectly. Bench fee was $89.  And it sounds surprisingly clean and really rips. Also have a Yamaha CR 450 bought new in 1976 cleaned up, replaced a couple bulbs, and it also works nicely, though the right channel has just started cutting out. 

I have quite a few vintage or old amps that I use every day. In my living room system I have a Thredhold S200 class A amp running through an Audio Resesrch SP1 preamp into Wilson Watt/ Puppies.

    The Threshold I got was a one owner who had it serviced before I bought it, new caps,etc.. It works and sound very nice. I also have a Krell KSA 150 which I bought after it was serviced by the previous owner. It’s my main amp in my dedicated system and I will never part with it. 
  Some older gear is just as nice sounding as newer stuff, maybe not as low a noise floor and the cosmetics might not be up to snuff for the wife but I wholeheartedly believe you can get some excellent equipment at good prices that will last another 20 years.

   Then at that age they probably would be collector items and fetch a good price on the market. Don’t be afraid to take the plunge and buy vintage gear if it’s been properly maintained. I haven’t regretted one purchase yet and I have a ton of vintage gear.

Was listening to a couple of days ago with a friend's Dynaco ST-70 which he had it recapped a few years back. He claimed that he spent some $$ to put in premium parts. Well that really paid off. Driving some JBL speakers, they really sound great. but he claimed that before the re-cap, the music was really unlistenable. Those ST70 he got were from the 70's and was never recap till recently.

Tinned Compressed Air with a Straw Nozzle and Deoxit is a real friend when entering the inner sanctity of the Vintage Circuits, Panel Control Dials and connections scream their thank you when getting Deoxit Treated from the Devices innards. 

Many Many sing once more with a few minutes of this care being administered.  

I bought a gently used B&K ST-202 power amp in the early '90s. That thing worked perfectly from day-1 to now. Sounds pretty good, too.

 I have 3 power amps, 2 vintage and a newer one. I like my old Phase Linear 400 Series 2 amp. Sounds as good as anything newer IMO. Could do with larger power supply caps and and more reliable output transistors. But for that investment it would well worth it. 400 watt amplifiers are insanely expensive now.

I own and use daily a Krell 300cx amp. Original owner since 2002, capped by Krell about 8 years ago, never had one hiccup with this melodious but powerful amp. Won't leave it until it leaves me. So if an amp is well-cared for and from a high reputation mfr., go for it. Neal

Hi Roxy.  I have a 30yo Denon PMA-520 that used to sound great.  I am the original owner, bought it from the original Magnolia HiFi in Seattle back in 1995.  It has sat in climate-controlled storage for the last 18 years or so, unused.  I fired it up a couple of months ago, let it sit for a few days before running a signal through it, then played it and it sounded quite wooly.  I suspect I need to have it re-capped before I pass it on to my daughter.

I don't know if it makes a difference if a device has been used regularly over many years or if it has sat unused for many years.  My gut tells me that sitting unused has more of a detrimental effect on capacitors.  Others more knowledgeable than me might be able to shed some light on that question.

@ronmen 

As stated above, gear stored for many years should not be plugged into the wall. It needs to be visually inspected and if everything looks ok then it needs to be plugged into a variac and brought up to line voltage progressively over a period of 12 to 24 hours. That lets capacitors reform.

@devinplombier

Hey Devin.  So, I visually inspected it first - no leakage or obvious signs of trouble.  The question is, since I have already plugged it in and tried it, is it too late now to go back and put it on a variac as you suggested.  It was probably 4 months ago that I fired it up after about 18 years in storage.

Question two: If you had two amplifiers of equal age, let's say 30 years old, one had been used almost daily for those 30 years and one had sat for 20 years unused, would one be more likely than the other to need a re-cap?

@ronmen 

The idea of the variac is to let dried-out caps reform progressively and spare them the full blast of inrush current while in a compromised state. So going back on the variac at this point is unlikely to make a difference.

Re question 2... a lot happens to electronics in 20 years, both actively used and stored. So... it depends.

That said, I think the compulsive hand-wringing over capacitors (while glossing over everything else) that seems to afflict many in the audiophile community is misguided. A number of potential issues with vintage gear are more important than caps.

@devinplombier

Does that mean you do not have an opinion on the specific question?  Also, what would you consider the more important issues?  'Just to be clear, I'm not trying to be antagonistic.  Please don't interpret my questions that way.  I'm just trying to learn. Thanks.

All well over 20 years, the newest is a Bryston 6BSST. I also still use a Bryston 4BST, 7BST and 10B Sub crossover.

Years ago my dad gave me his MC2125 and C28. I had them serviced and find them fun to listen to but lack the clarity of more modern amps. That said I’d rather listen to this pair over many sub $2500(I think equal value after you pull out the nostalgia value) pre/amps/integrateds, but not compared to many better amps I’ve had.

There is something about this pairing that brings me back 30 years, whether tone or timing or whatever, so there is that piece of the puzzle that’s fun too. 

@ronmen 

No worries, these are good questions.

I don’t have a strong opinion as to whether an amp used daily for 30 years is more likely to need a recap than one that has sat unused for 20 years because caps will deteriorate in both cases, albeit for different reasons. Personally, I would pick the unused one if it hasn’t been plugged in / turned on yet.

Bias drift is quite common and can raise internal components’ operating temperature to dangerous levels (dangerous for the amp that is) if left uncorrected, causing an amp to slowly cook itself to death in some cases. Cooked PCBs are not salvageable past a certain point of doneness, making the amp essentially unrepairable. Such total loss may be uncommon, but it is still best practice to check bias current and DC offset, and adjust them as needed, every couple of years.

Driver and output transistor failure can have significant negative consequences. Same for power supply failure, depending on an amp’s topology.

Granted, modern amps are equipped with protection circuits that are designed to save speakers from being destroyed by excessive DC offset. But early SS amps raw-dogged it; Phase Linear - known for building 300+ wpc amps in the early 1970s out of automotive electronic-ignition transistors, as well as for being the first known audio-related manifestation of Bob Carver - was affectionately nicknamed Flame Linear 🤣

Regular preventative maintenance is desirable with early SS amps.

@devinplombier regular preventative maintenance is desirable even with more modern amplifiers as they age. My 33 year old Krell amp has more protection circuits than a lot of modern amps have, but that doesn't mean it can't still have a catastrophic failure.

@invalid 

Of course, although it’s always nice to know that if it does it’s less likely to take your speakers out. In any event, I would definitely recommend a sensible preventative maintenance program. Out of curiosity, which Krell do you have?

@devinplombier  Krell ksa 300s

+1, I use and rotate in my twenty five+ year old Forte' Audio 3/1A (Pass Labs) Class A 50 watt stereo amplifier [Jon Soderberg upgraded last year]. 

Has a nice large transformer, Toshiba Mosfet output transistors. Four new power capacitors, and bridge rectifier's.  True Class A, 50w@8ohm, 80w@4ohm. Sounds fantastic and competes with many expensive amplifiers today. Also have the matching Forte' Audio line stage preamplifier with dual pre-outs in stock form. 

While I use my 6SN7 tube preamplifier with it, rotating my mono tube amps in/out, I've been playing this SS amp for the past year every other weekend. Liking it quite a bit. I might part with it to do the same upgrades with two of them as monos for my larger custom speakers just for fun. Not necessary, this stereo amp version is plenty on its own for speakers 90db+ efficiency.  This amp keeps me from using my tube amps due to how it performs and sounds as a true Class Amplifier.  Make sure you have a good tech who can check, upgrade, and freshen up your amp for you.  

If ever I will decide to buy a used amp . I will buy it from TMR audio . Because they meticulously inspect their used products. And I think you have 45 days to decide. If you like it , you can’ return it. To be sure call them.

Techs who work on high-end gear are scarce, and really good ones are rarer than flying pigs. They (justifiably) command high rates.

The downside of this is that at $100+/hr it doesn’t take long for a repair to become economically unfeasible, or the tech won’t touch it if it’s not straightforward and / or looks like it’s going to take a lot of research time. So there are definite plusses for dedicated audiophiles to learn how to do it for ourselves.

@invalid - KSA-300S are beautiful amps.

A couple of years ago I invested $2000 in refurbishing my 35 year old Nakamichi PA-7A MKII amp and CA-7A preamp.

Money well spent in my opinion.

I am running a pair of MacIntosh MC2100 SS Amplifiers that were built in the early to mid 1970s... one has been fully recapped; the other is (I believe) all original. They are fed by a PAS3 Tube Preamplifier that was built in 1968 I believe. The PAS3 has had a new power supply installed, and new tubes. Other than that I believe all the caps and transistors are original. 

Sound quality is pretty much identical from each amp. The only issue I have found is that the all-original amp runs a little warmer than the recapped unit. I will be recapping the original unit within the next few months, just to be on the safe side.

I think there is a certain 'charm' and sound quality to the vintage stuff that the modern units just don't have... but that is just my own opinion. I do think, objectively, that if you have a desire to run the vintage equipment you should try it. In reality, if you start by purchasing good quality brands that are still in good shape - you shouldn't run into anything that would be any more difficult to remedy than if you had an issue with a modern unit.

@devinplombier  yes, some amplifiers are not worth putting too much money into repairing, the better built ones like many of the old Krell amps is a different story. To buy a modern class A/B amplifier built like the old Krell amps would cost tens of thousands.

Still using my sunfire amp from late 90s in my second system. Sounds pretty darn good but not quite up to my Triode Lab PSet 45 monoblocks in my primary system. I’ve swapped them several times not and keep going back to the TL. There’s also a 10x cost difference so I probably shouldn’t be that surprised.

In 1980 I bought a Yamaha M2 Poweramp 240 w. Of channel weighs 70 lb. To purchase a 240 w amp today that's built as well as this one would cost me $5 to $6,000 or more. This amp was sold by Yamaha is a high-end home amp and also as a power amp for PA systems and concerts. I had a local tech that specializes in '70s and '80s amps only take it apart. Change relays that had corroded contacts because it had relay protection in several areas. Cleaned all the pots. Checked every capacitor. Checked all all transistors for proper specifications. All the parts that are inside these amps are subject to changing their specifications over time because of heat abuse, high voltage, low voltage spikes, whatever we're talking thousands of parts in these amps. Yes they will run perfectly for years and years and years. But if you want it to run like it was from the factory going through and and replacing the Hi-Spec parts that Yamaha put in with the high spec parts that are available today is the cheapest thing you can do. In the end I put $750 into the amp that I bought for $1,000 and it still is better than a $5,000 amp today. The amp is such a sweet piece of equipment. I purchased a second one because I'm going to buy at my speakers cost me a little more cuz it was having a problem when I got it. But now it sounds just as sweet. 

Yamaha is one of those engineering companies that just likes to do things top notch when they're selling a top-notch piece. If you look at their current offerings they have three levels of basically the same power amp. They're all supposed to be 100 w a channel but the quality of the construction as you move up becomes apparent as to why some of these ultra expensive amps do Excel at their craft. I've been an audiophile since 1975 and I've watched the industry grow up. I've been watching these companies grow up and it's always the company that goes to the nth degrant engineering that'll last today's modern high-end amplifiers are very well built. Use quality components. My choice is for the vintage because they just look cool. Enjoy whatever you have and enjoy upgrading it