Help me with OLD tube amp!

[soundguruman]

[QUOTE=Rhodesplyr;327801]Complete bullshit. The Mojo is in the circuit and the transformers, not to mention largely in whatever speaker you connect it to and who's playing guitar through it.

Now let's see if you can learn how to preserve a classic sound...
instead of gutting it.

Just cling to your oscilloscope. That's as far as you will progress.

It's called "the Music Electronics Forum."
You know the electronics part, but witness the "Music" part, that you are so UN-familiar with.

from the economic standpoint:
Although it may seem illogical to you,
Amp with original parts and original construction is worth more money, besides being more desirable to collector, or musician.
Amp with replaced parts is worth less money, and is less desirable blah blah blah. Except in certain cases, where expensive high end parts have been added...

They never sound the same.
The makers of "new old style caps" want you to "think" they do.

If you gut all the old coupling caps, it will sound sterile. The old mojo be gone.
Try to use the old ones, unless they are really shorted or "too" leaky, for the amp to function.
Don't be obsessed with "out of tolerance" parts. It's the AGE that makes the tone.

The most experienced LEAVE the old coupling caps, and try to use them. This is considered the most "proper" approach.
The MOJO dwells in the old parts. That's why try to preserve oldness of it....

It was Drewl who so wisely spake:
"I bet it will sound pretty good as is.
You can always mod or tweak the circuit after you get it working."

OK, now here's a Drewl with some common sense. OUTSTANDING approach!
257 thumbs up, and 1000 stars.

Sorry, but you are missing 50% of it. The part that the musician appreciates, you don't even consider it.
AND, until you achieve competency with an electric guitar, you will NEVER consider it.

[Leo_Gnardo]

I service 1950s Hammond Organs and Leslie speakers all the time, and I know organ dealers who try to dust off an organ and sell it without replacing the mid-50s paper coupling caps. Almost invariably, within a few months of being put back into regular use, these timebombs start to cause problems. I've seen many cases where these paper caps give up before the original electrolytics.

I've also read a book on amp repair written in the 1950s in which the author states that problems in an amp are most frequently caused by failed capacitors. No one was under any illusions back then about their reliability.

Having had a Hammond catch fire on stage one day - I'd agree with the preventive maintenance you recommend. NOBODY in the paying crowd is gonna walk out because the instrument or amp has a set of good reliable caps in it. When the show stops dead in a cloud of stinky smoke, they want their money back, every one of 'em. Failing equipment = not good for business, plus it builds a BAD reputation, not conducive to future business. Promoters DO talk to each other. And email. And msg. Bad news travels FAST. Also, 99% of the mojo is in the brain-hand connections of the musicians.

[soundguruman]

Yes, if you use old coupling caps
as so many collector and musician do...
your amp will explode and blaze with fury.
Doom is eminent.

[Leo_Gnardo]

Yes, if you use old coupling caps
as so many collector and musician do...
your amp will explode and blaze with fury.
Doom is eminent.

IMminent, you mean. Better than the Sunday funnies you are SGM! No, smoking & smoldering is mostly what happens. It's Sunday morning, you should be doing that with some local Humboldt cash-crop. Goes good with pancakes. If that doesn't calm your nerves, send it here & I'll find out what's wrong with it...

Also note the # of posts - 666 - I saved it especially for you. I know you'd appreciate that!

[drewl]

Boy, things went south here pretty quickly.

It's easy enough to test caps for leakage or failure.
If they are bad, they have to go, simple as that.

[eschertron]

Boy, things went south here pretty quickly.

Looks to me as if oscillating gets to see the best and worst of MEF on his very first posting. Good work, everybody!

[soundguruman]

The standard followed world wide by the most experienced techs FYI:

A. only the bad parts are removed, there is no wholesale replacement, just because "parts are old."
B. We (meaning experienced techs) always try to keep every classic tube amp "as original as possible."
C. We (meaning experienced techs, collectors, musicians) consider "gutting" parts out of a classic tube amp: "bad practice."
D. We (meaning experienced techs) never assume that parts are bad, or should be replaced, because "they are old."

"It's easy enough to test caps for leakage or failure.
If they are bad, they have to go, simple as that." "

Why is it that Drewl seems to be the only person here who speaks what is considered "good practice?"

The majority (in fact all of them) of tube amp preservationists, and collectors of tube amps, DO NOT change parts, because they "are old."
They only do this when the parts FAIL.
That IS the excepted and practiced standard.

What collector is looking for: Amps that the inexperienced have not gutted. "as original as possible."
What collector does not buy: Amps that have had a bunch of parts replaced, by inexperienced tech, "because they were old."

There are a lot of old tube amps, but the number of amps which have not been unnecessarily screwed around with are becoming fewer and fewer.
Too bad for tube amps. They deserve to be taken care of, not gutted.

[Rhodesplyr]

As an experienced tube amp tech myself, allow me to clarify without all the posturing, use of bold face type, and misspellings ('excepted'). You are making massive generalizations based on my recommendation in a specific instance to replace paper capacitors.

I don't "gut" amps. On the basis of considerable experience, I know which parts are likely to fail and which to leave in place because they are likely to last. For example, in 1950s Hammond amps, you find two styles of paper capacitors made by the John E. Fast Company. One style fails. These get replaced. The other style was a special high-reliability paper capacitor. These stay because I've never seen one fail. However, the vast majority of paper capacitors from the 1950s are either leaking DC and/or measure nothing like they did when new. Their ESR has increased by factors of 10 or more, and their capacitance has increased 30-50% due to moisture infiltration. As an example, I restored a 1952 Flot-A-Tone amp for a customer. If you put 100V on any of the bumblebee caps in circuit, you'd find 15-30V on the other side.

Most of my customers are performing musicians who need to have their amps working reliably. That means that they need to be reasonably sure that they won't blow up if they use them for a performance or a recording session. I go to great pains sometimes to use parts that are as vintage-correct as possible, including using boutique paper capacitors if the customer wants to go that route, and I recone blown speakers with parts as close to the originals as possible, including paper voice coil formers, if available.

Amp collectors are a distinctly different group. They often don't seem to care if the amp works or not, or if it can be counted on for a performance or a session. I don't really understand or subscribe to that mentality since I don't understand what they do with non-functional amps. Do they set them on altars and worship them every day? My position is that the builders of these amps intended them to be used to make music and that keeping them functional honors those intentions. If someone wants to keep an amp as a museum-piece object, that's fine, as long as you don't try to use it.

Like I said above, we have another tech in town who takes your approach. He charges people ~$300-$600 to install a three-wire cord and maybe replace one or two completely failed parts. Then, when the musician tries to use the amp, parts that fail predictably start to fail, often at inopportune moments. In one of these, a Fender Super Reverb, his approach caused the amp to burn up a pair of Sylvania 7581s that the amp's owner couldn't afford to replace. I could give five or six more examples. One by one, his customers are migrating to me and another tech in town.

And, believe me, you do not want to get a call about how a 1957 B-3 is breaking down in front of an entire church congregation on Christmas Eve or on Easter Sunday. They're not going to care one damn bit about how you were trying to keep the organ's preamp all-original. They need the show to go on, period.

[armillary]

Hi oscillating,

The Rauland 1916 is a great chassis to turn into a Fender Deluxe 5C3 clone. I wouldn't call it an easy first project though. You basically remove everything but the transformers and sockets from the chassis and add back the five tubes that make up the 5C3 (6sc7, 6sc7, 6v6, 6v6 and 5y3). The ceramic 250 ohm resistor can be reused, but there's not much else that matches the Fender schematic. Even the pots are replaced. But the result is worth it. Loud and honky and totally tweed.

A Champ would be a better first project though. You could save the Rauland 1916 for a second project. Or PM me should you decide to part with it.