Opinions on Recapping vs Repairing Vintage Receivers

I once fully recapped an st-70 with orange drops and wasn’t happy with the outcome. Not sure if it was the cap choice, preamp (dynaco 4 pre) or speakers (bozak symphonies), but all the hype I’d read about the st-70 was not there for me….the amp and rest of the gear were moved on promptly.
It might have been the preamp if that was a PAT-4 . I built one. It seemed to work fine but I hated the sound of it. So I sold it and built another. It sounded exactly the same. So I sold that one and bought a SWTP 198/A That sounded better but it was still awful and a certain combo of tone controls would oscillate. So I gave that one away and bought a MacIntosh C-20 which I was very happy with for a long time.
 

JohnVF

Administrator
Staff member
It might have been the preamp if that was a PAT-4 . I built one. It seemed to work fine but I hated the sound of it. So I sold it and built another. It sounded exactly the same. So I sold that one and bought a SWTP 198/A That sounded better but it was still awful and a certain combo of tone controls would oscillate. So I gave that one away and bought a MacIntosh C-20 which I was very happy with for a long time.
The PAT-4 was the worst sounding bit of hi fi gear I have ever owned. I had hoped mine was just in bad shape but I've heard others and... I'll just say I'm not in search of any more of them.
 
I don't know what they did wrong with the PAT 4. The PAT 5 was not a bad piece of gear although I never owned one.

The Akitika kit guy has lots of upgrade kits for those units. I think you could totally replace the gut inside either of them. But he also has a kit or built preamp that is reasonably priced so you could skip the rebuild.
 

JohnVF

Administrator
Staff member
If I was going to mod something, I wouldn't start with the worst thing I'd ever heard :).

I've heard many Stereo 70s, and each one sounded completely different than the last. The one I had was a very special piece, sounded incredible both for what it was, and up against some better on paper amps, and I have no idea why I sold it.
 

Audionut

Next Round Is On Me
It might have been the preamp if that was a PAT-4 . I built one. It seemed to work fine but I hated the sound of it. So I sold it and built another. It sounded exactly the same. So I sold that one and bought a SWTP 198/A That sounded better but it was still awful and a certain combo of tone controls would oscillate. So I gave that one away and bought a MacIntosh C-20 which I was very happy with for a long time.
Definitely a Pat-4, by the looks of everyones post, it was a smart choice moving it along. It left with a neat looking tuner that had the magic eye?
I could see a C-20 being leaps and bounds better too!
 
I’m definitely in the full recap camp, especially when talking about electrolytics. An aged component on the brink of failure does not “sound better” than a fresh modern equivalent.

Plus, I like to be able to push the power button without having to have all fingers and toes crossed.
Many of my current pieces employ a simple design layout so it wouldn’t be a daunting task to tackle. I believe the designer of one of my pieces even suggested a recap would be his recommendation in order to keep the unit long lasting and without issues developing, but wasn’t heavy handed about it. I’m purposely leaving his name out of the post in case I’m erroneously recalling this interchange, but he’s well respected and active on some specific boards that draw some well recognized industry bigwigs.

I’ve another piece here with an external power supply. The unit sounds great but the external power supply a touch noisy. The beauty of this is I can tackle the power supply alone and not rush into the rest of the unit. The piece is around 30 years old and it’s a well documented unit- a mild upgrade on power supply capacitors and a very few additional handful of parts and I would feel confident with the unit.

But you also get to thinking- how are the rest of the capacitors aging? They look fine visually on the outside, with no weeping of fluids or bulging of bodies, and with only a fistful or two of caps to replace, that could buy you thirty-plus more years of not worrying about how the caps are holding up under the lid, and wouldn’t be an expensive proposition to tackle.

So I hear what you’re saying.

Some of my other pieces however, are a bit more involved. A full recap would be expensive and I’m not interested in the sweat equity to try and tackle it myself, and not so sure I’m that enamored with the pieces to put that cash into them. That does keep a thought in the back of my head, that like many a vintage acquisition from other hobbies, things occasionally spring up and require attention and repair. The “what if” gremlin sits in the back of your head, reminding you it’s not “if”, but “when”….
 

JoeThePop

Known member
I repair scientific equipment at my day job and have been an audio nut for 53 years and built a lot of things.

I am firmly in the if it ain't broke , don't fix it camp.

My system which was new in the late seventies was taken down for a move. I was anticipating a rebuild on some Pioneer M-22 Toasters. But I found a young friend with an enviable bench which includes a relatively recent HP distortion analyzer. All that late seventies stuff still measures like a preamp.

I would also worry alot about who was doing such a recap and rebuild. There are improved capacitors available now over what was available "back in the day" But is the person doing the job fastidious enough to do it better than the engineers that built it the first time.

I personally find the recap fashion to be one of those things that seems to me to be an effort to releave people of money.
Check whether or not it meets its factory specs or its original known performance and if it is close leave it at that.

One of the amps in the rather large pile was a Quad 405 current dumping amp. also from the late seventies early eighties.
It was the first one we checked. It measured so well that the young man whose bench it was ,said, I have to get myself one of those.
There are kits of parts to rebuild them and I had looked into those. But nah I'll wait till something pops. ymmv

I have a 34 year-old Yamaha receiver that I bought new which I plan on using more after we move, and I'm basically of the same opinion; "if it ain't broke , don't fix it". What I will do, is before I get real serious of mating up some new speakers to it, is have it checked by a reputable tech to see if it is operating within manufacturer specs. Just like you managed to do with your young friend. If it is operating to spec, I will leave well enough alone. I have limited funds and those will be going to go towards speakers.
 

fiddlefye

Senior Member
One other aspect of rebuilding older gear is that with a bit of thought we get to see how things have aged and maybe make some changes to improve future longevity. On a few pieces I've had redone it was apparent after a few decades of use that certain components were heating a board more than was healthy and we added the odd extra heat sink to help things out.
 
That goes for capacitors too. Modern caps are significantly smaller than even 70's caps. So you can up the voltage.
Makes them fit better too. If I see 50v caps (especially if they've failed), I'll use 63v for example.
 

fiddlefye

Senior Member
That goes for capacitors too. Modern caps are significantly smaller than even 70's caps. So you can up the voltage.
Makes them fit better too. If I see 50v caps (especially if they've failed), I'll use 63v for example.
Hindsight can be 20/20 if we actually look, right?
 
Old gear gets at least the power supplies recappped and the inrush diodes replaced. Sometimes the whole cap lot goes, it’s peace of mind. I have a couple things here now which need the treatment.
 
I have a solid state tech who I have come to trust because he is very disciplined about making sure components new (being installed) and old (already in place) meet or exceed performance consistently matched across all these parts. Regardless of what grade parts are used (and I do push him to use the best reasonable parts for the unit) I think this careful assessment is an important aspect. He just completed my 2270 which has had much work over the years already and now it really sounds astounding as never before. It was well worth the refresh despite good performance before the work. I'm smitten. I think good parts and good careful tech work is worth it in vintage gear of a certain design caliber. I have found that this diligence also has kept my vintage gear reliable.

IMHO, the real good deal is to find a piece which has been recently restored and buy that even if you pay a little more. That's the unit that will save the most as you are benefitting from someone else's expenditures which are probably not being fully recouped in the sale. If the piece is coming from a "good home" and not a careless flipper situation, there are probably many system variables and considerations for the decision to sell which may not be relative to you as the new owner.

...and yes in firm agreement that this is the nicest damn forum I have ever encountered. I'm a newbie invited by a friend here after being a long time member of other forums and must say it is really refreshing here!
 
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