to re-cap or not to re-cap Mcintosh C20

[cocovinyl176]

Hi All,

I have a c20 I recently sent to a tech. Prior to bringing it in, I was pretty confident that there were for sure leaks and a recapping was inevitable. After benching it, good News, all of the original bumble bees are in great shape and in tact. As it turns out, I need some new tubes and a good cleaning. My dilemma is, even with the old caps in good shape, do I still recap? I have heard about the mystic of these bumble bees on one hand, but have also heard that replacing them with modern caps will provide more depth. I understand a collector may want to have this pre all original. is there that much of a significant change in dynamics should I chose to replace all of them? Also, on another note, can anyone recommend (non-NOS) manufactured tubes for this pre? I plan to uniform them with one brand, even though I have a few tele's that are still in good shape.

thanks as always-

 

[twiiii]

If you bought a collectors Ferrari that was 20 years old would you drive it with original tires? Of course not.

 

[cocovinyl176]

If you bought a collectors Ferrari that was 20 years old would you drive it with original tires? Of course not.

I get the analogy, but there are expiration dates on tires, whether they're used or been sitting on a shelf for 20 in it's brand new state. Do these things have that same "date"

 

[primosounds]

I get the analogy, but there are expiration dates on tires, whether they're used or been sitting on a shelf for 20 in it's brand new state. Do these things have that same "date"

How do you know that the original caps are not leaking DC? While the originals have "sentimental" value you can always ask the rebuilder to save all the original parts and give them to you so you can pass them on if someone wants them.
If you are going to replace the caps the ones that are most similar in construction are the paper in oil type. I did a c20 or c22 with Sprague VitaminQ that sounded very good afterwards.

 

[cocovinyl176]

How do you know that the original caps are not leaking DC? While the originals have "sentimental" value you can always ask the rebuilder to save all the original parts and give them to you so you can pass them on if someone wants them.
If you are going to replace the caps the ones that are most similar in construction are the paper in oil type. I did a c20 or c22 with Sprague VitaminQ that sounded very good afterwards.

I tend to agree with what you're both saying. Maybe i'll recap and save them all in the event I ever sell the unit. Thinking of using Nichicon, I thought I recall Terry Dewick mentioning in a post somewhere.

 

[gadget73]

I have not had good luck with old bumblebee caps, unless I was trying to find leaky ones. Most of the ones I've subjected to my ancient Solar cap tester have failed.

 

[Pio1980]

You can check for leakage in circuit if you know what you are doing. What is critical is DC leakage thru blocking/coupling caps between stages into controls and tube grids.

 

[4-2-7]

My dilemma is, even with the old caps in good shape, do I still recap?

I would leave it as is, the tech just told you that they checked out, now you online asking others who have not see your amp.

 

[primosounds]

If you are going to sell this , sell it as is and that would certainly be more "attractive" if were totally stock. If you are going to keep it for your own listening pleasure then would you not want it to be performing the best that it can? Even back in the 1960s parts were built to a certain life span. I don't think that 50+ years was the lifespan that these parts were spec'd at. But if you like the way it sounds the way it is and there are no issues, I guess you can roll the dice and see how long it operates without a problem.

 

[gadget73]

It might be worth at least asking how they were checked. Checking them for value won't cut it. If they were checked for leakage at full working voltage and passed, that will do.

but yeah, if its an item to sell, leave it be, send it to it's next home and let whoever buys it do what they want.

 

[Champco]

There is something to vintage audio gear that works properly and is unmolested. It is what I prefer when I can.

 

[cocovinyl176]

It might be worth at least asking how they were checked. Checking them for value won't cut it. If they were checked for leakage at full working voltage and passed, that will do.

but yeah, if its an item to sell, leave it be, send it to it's next home and let whoever buys it do what they want.

they were ck'd for leakage at full voltage. Aside from maintaining its original state untouched, are there any auditable benefits? is there anyone here for believes it sounds better as built in 1959?

 

[4-2-7]

There is something to vintage audio gear that works properly and is unmolested. It is what I prefer when I can.

This is what I like and tend to leave things alone. Unless it will harm the amp like Sansui Black Flags.

they were ck'd for leakage at full voltage.

Very good

Aside from maintaining its original state untouched, are there any auditable benefits?

This you will never know because it's impossible to listen side by side and it's also a subjective synopsis.

is there anyone here for believes it sounds better as built in 1959?

Well good sound is built whenever it was built, it could have been yesterday or 50 years ago. However I don't expect a 50 year old amp to sound like it did new, what's important is how it sounds now. I look at it like this, I have some old jeans or shoes that just fit right and are comfortable to me. Going to the store and buying new ones might work but wouldn't be as comfortable, at least not yet, nor is it guaranteed they ever will. The thing is, it was the uniqueness, individuality and test of time that made my old jeans and shoes my favorite pair, sometimes, most of the time this can never be duplicated.

 

[cocovinyl176]

This is what I like and tend to leave things alone. Unless it will harm the amp like Sansui Black Flags.


Very good

This you will never know because it's impossible to listen side by side and it's also a subjective synopsis.


Well good sound is built whenever it was built, it could have been yesterday or 50 years ago. However I don't expect a 50 year old amp to sound like it did new, what's important is how it sounds now. I look at it like this, I have some old jeans or shoes that just fit right and are comfortable to me. Going to the store and buying new ones might work but wouldn't be as comfortable, at least not yet, nor is it guaranteed they ever will. The thing is, it was the uniqueness, individuality and test of time that made my old jeans and shoes my favorite pair, sometimes, most of the time this can never be duplicated.

thanks you. funny, even with the failing tubes, the thing sounded fantastic. My hope is that once I replace all the tubes that I may be more impressed, but doubtful I'll notice the difference. it may be so subtle.

 

[4-2-7]

thanks you. funny, even with the failing tubes, the thing sounded fantastic. My hope is that once I replace all the tubes that I may be more impressed, but doubtful I'll notice the difference. it may be so subtle.

Now tubes are another matter and should be sampled, tested and changed when needed. Some of the signal tubes might be just fine and you can match them in specific areas like the phono stage output. And buy new/used for other areas to replace bad one.

 

[cocovinyl176]

Now tubes are another matter and should be sampled, tested and changed when needed. Some of the signal tubes might be just fine and you can match them in specific areas like the phono stage output. And buy new/used for other areas to replace bad one.

2 out of the 5 12ax7 org Tele's were shot, 1was very good, the other 2 on their way out with limited life. so, I figure to buy all new tubes.NOS would be nice, but think it's a tad overpriced and over hyped. Ive read good thigs about Gold lion/ JJ Telsa gold plates.

 

[Pio1980]

they were ck'd for leakage at full voltage. Aside from maintaining its original state untouched, are there any auditable benefits? is there anyone here for believes it sounds better as built in 1959?

"Different" is easy, "better" not so much". I don't consider what's thought of as classic "tube sound" accurate, others love it and prefer it to "accurate". The old oily paper caps, carbon composition resistors, carbon track wiper pots, and lack of power rail bypassing, are all, with the tubes and complex signal path, part of that over-all "sound". Change anything, the sound changes with it.
It's a classic for sure, but not the world's greatest preamp by comparison.

 

[trainbuftony]

It all depends on what you want to do.
Want to listen to it at its best, then replace everything in it with the best modern parts. Low noise resistors, and premium caps.

You could leave everything exaxtly how it was originally, in order to maximize resale value to collectors, who wont want any modern parts. Its worth a lot in working condition with all original parts, and so is a 67 camaro with original tires.

You could fix whats wrong and leave the rest, and enjoy having a nearly original McIntosh. Personally i would replace every part in it, and think long and hard about what components are worthy, then it would of course stay with me until i die...

 

[primosounds]

2 out of the 5 12ax7 org Tele's were shot, 1was very good, the other 2 on their way out with limited life. so, I figure to buy all new tubes.NOS would be nice, but think it's a tad overpriced and over hyped. Ive read good thigs about Gold lion/ JJ Telsa gold plates.

Telefunken ecc83 have a reputation that is deserved but procuring replacements can be give people sticker shock. A long time ago I started collecting all brands of vintage 12ax7 when i was using them in my equipment and tried different brands just to see what difference that would make in sound quality. One thing i learned was that a strong tube was important to performance. So, new tubes always had the advantage because they had good emission. Now, how long that ability lasts is maybe a different story vs vintage tubes.
When i rebuilt my buddy's Mac preamp i auditioned it in my main system for a bit just to know what it sounded like so after rebuilding i had a frame of reference to speak to after installing the new caps. And i thought the new caps improved the sound in areas of dynamics and soundstage. The new parts did not have enough time to break in so overall i felt the new parts were an improvement with around 10+ hours of use. As always YMMV.

 

[gadget73]

I strongly suspect that the components selected in 1959 wouldn't be what was picked if they had access to modern parts. The engineers made a selection based on what would do the job, what was available, and what it cost. I have no belief in "magic" in paper capacitors or carbon comp resistors.

All that said, I increasingly subscribe to the golden rule of equipment: if it is not broken, do not screw with it. If the failure-prone parts have been tested and blessed as good, leave it alone. You have some extra wiggle room here since its a preamp. If one of those caps starts leaking, its not going to melt down a power tube. Its not impossible to take out a 12ax7 but more likely it'll just sound funny.