Vintage amp safety question here...

[pdf64]

Regarding the cap memory effect mentioned, see http://www.rubycon.co.jp/en/products/alumi/pdf/RecoveryVoltage.pdf

 

[axpro]

To add my $0.02 Canadian funds.... Don't use the amp. DEFINITELY don't gig with it... until you take care of it. We had one get traded in at the shop I work at (not the same model, but similar type... Garnet "Stencil" amps as they call them up here) To be honest the amps like this don't usually sound "great" even as a funky sort of thing... and they will act like you are french kissing a light socket with any part failure, and you are counting on 50 year old parts, used in an amp that probably lived in someone's attic or basement for 40 years, keeping you safe.

You list your location as Houston, there HAS to be an amp tech near you. Maybe not one who will do it for Beer, but someone in your area knows tube amps... you just gotta search them out

 

[Tbone135]

To add my $0.02 Canadian funds.... Don't use the amp. DEFINITELY don't gig with it... until you take care of it. We had one get traded in at the shop I work at (not the same model, but similar type... Garnet "Stencil" amps as they call them up here) To be honest the amps like this don't usually sound "great" even as a funky sort of thing... and they will act like you are french kissing a light socket with any part failure, and you are counting on 50 year old parts, used in an amp that probably lived in someone's attic or basement for 40 years, keeping you safe.

You list your location as Houston, there HAS to be an amp tech near you. Maybe not one who will do it for Beer, but someone in your area knows tube amps... you just gotta search them out

Yeah, there's a really good tech on the other side of Houston. Not too many good or dependable guys elsewhere in town. If I don't return the amp, I'll make a point to get it checked out.

Y'all should see this thing, I thought it was a reissue, it's so clean.

 

[Jeff Gehring]

Wow, if you can return the amp, that's sure what I'd recommend. Unless it sounds absolutely magical, it won't be worth the work it's gonna need.

 

[icr]

There is unlikely to be significant shocking DC coming through the mains. Isolation transformers block DC, not AC. Some dangerous advice in this thread.

 

[Don A]

I've got some pix of a Dano Corporal that I installed an isolation transformer in for a customer; I can post them if requested. For myself, I wouldn't want to own an amp with a line-derived power supply. Usually they are small, cheaply built, and lightweight as a result. By the time you shell out for a capable repair to install the isolation transformer and do what else is needed (you know it's going to need caps at a minimum) you are upside down on the amp financially, and it weighs a good bit more than it did before. I found the only safe place in the Dano for installing the transformer was on the cabinet floor, as there was no way that the masonite they used for the chassis would hold up a chunk of iron the size of a small fist.

This is why my Sears 5XL sits w/o an isolation transformer while I play other amps.

 

[pdf64]

There is unlikely to be significant shocking DC coming through the mains. Isolation transformers block DC, not AC. Some dangerous advice in this thread.

Please ignore the above post; whilst it is correct to state that transformers block dc not ac, a direct connection to mains current is not tolerable in guitar amp circuits. All power must be provided be via an isolation transformer so as to prevent this.

 

[Kyle B]

There is unlikely to be significant shocking DC coming through the mains. Isolation transformers block DC, not AC. Some dangerous advice in this thread.

Pretty good laymans explanation here (close to laymans as possible... it's still a kinda heady concept)

Another way to look at it...

If it were indeed "ok" to not isolate, then why does every current production amplifier provide this isolation? It would be far cheaper to wire up the heaters 'old school' style (no transformer).

 

[UsableThought]

Pretty good laymans explanation here (close to laymans as possible... it's still a kinda heady concept)

That's actually pretty good, including the "oops" situation where if your body interrupts the "isolated" circuit, well, you know. You can protect against some bad things some of the time but not all bad things all of the time. I think PT Barnum said that as he was slipping on some elephant poop.

Same thing with GFCI outlets. They are really good for speeding up earthing protection (that is my crude way of thinking of it). But they won't help you if you manage to insert your body in series with a high voltage circuit without earthing involved. I have installed them in my workshop anyway.

 

[J M Fahey]

There is unlikely to be significant shocking DC coming through the mains. Isolation transformers block DC, not AC. Some dangerous advice in this thread.

Unclear comment.

1) who mentioned DC?

2) if you mean DC being dangerous and AC being safe or viceversa, truth is DC mains will kill you as dead as AC mains will.

3) that fight was run 130 years ago, :

Not surprised remnants of what was said in those days still remains, Edison thought nothing was way too gross if it helped him "win", here's an Edison company film showing an elephant being electrocuted in 1903, "showing AC is dangerous" ... viewer discretion advised:

https://upload.wikimedia.org/wikipe...son_-_Electrocuting_an_Elephant.ogv.360p.webm

 

[icr]

Perhaps I was not clear. AC is NOT SAFE but AC is freely passed by an isolation tranformer and that AC can KILL you. That is why there is dangerous information in this thread!

 

[UsableThought]

AC is freely passed by an isolation tranformer and that AC can KILL you. That is why there is dangerous information in this thread!

Obviously everyone here is concerned about safety; and it sounds like you are too. But so far it is not clear what your objection is.

It would be helpful if you could quote an example, word for word, of a specific statement that you believe is dangerous. Otherwise you may be seen as flaming the entire thread so far, which I'm sure is not your intention.

It would also be helpful if you could explain more clearly what you are objecting to with isolation transformers. To say that "AC is freely passed by an isolation transformer" is too vague - "freely passed" could mean almost anything. Can you say what you mean using terms and descriptions that are more precise & more commonly used?

As Kyle B. has effectively pointed out, the only difference between the power transformer in a typical amp and an isolation transformer by that name is that the iso transformer is one-to-one rather than stepping up or stepping down. That's literally the only difference. They all isolate the same way. So as I say, it's not clear what you're objecting to.

 

[Structo]

Don't use a screwdriver to short out caps unless you want to arc weld.

 

[DGTCrazy]

*(This is not intended towards those who have been trained and can competently work on amps).

Folks.........remember this is the Internet. If you have an issue with your Vintage Amp......or any amp for that matter, and you're not 1000% versed in safely dealing with Electronics, especially those that are older and pose a great risk even when unplugged, please consult a qualified Amp Technician. IMO, they are worth their weight in gold.

 

[Tbone135]

*(This is not intended towards those who have been trained and can competently work on amps).

Folks.........remember this is the Internet. If you have an issue with your Vintage Amp......or any amp for that matter, and you're not 1000% versed in safely dealing with Electronics, especially those that are older and pose a great risk even when unplugged, please consult a qualified Amp Technician. IMO, they are worth their weight in gold.

I am indeed taking it to a trustworthy tech here in Houston when I can. I have been amazed at the wide ranges in information I've read over the last few days and it's made my head spin. We have one really good tech here in Houston (sad to say) and he'll get to sort it out.

 

[TweeDLX]

I am indeed taking it to a trustworthy tech here in Houston when I can. I have been amazed at the wide ranges in information I've read over the last few days and it's made my head spin. We have one really good tech here in Houston (sad to say) and he'll get to sort it out.

Very good decision!

 

[Tbone135]

Very good decision!

Yes, I am entirely too important to get shocked.

 

[TweeDLX]

Right!

 

[icr]

 

[Kyle B]

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