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Post subject: Re: DRRI- solid state rectifier
Posted: Tue Apr 23, 2013 9:54 am
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bluesky636 wrote:
stratele52, Arjay, and I all design, build, and repair tube amplifiers. And your qualifications are what? :roll:


I'm certain that like you, he has a college degree in electrical engineering and circuit design. Or like me, has a First Class Radio Telephone Technician's license with a radar endorsement from the FCC. And like Stratele and both of us, has spen thousands of hours of bench time repairing hundreds of Fender amps and guitars.

We should all bow down and kiss his ring......

:roll:

Arjay

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Post subject: Re: DRRI- solid state rectifier
Posted: Tue Apr 23, 2013 9:58 am
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Retroverbial wrote:
bluesky636 wrote:
stratele52, Arjay, and I all design, build, and repair tube amplifiers. And your qualifications are what? :roll:


I'm certain that like you, he has a college degree in electrical engineering and circuit design. Or like me, has a First Class Radio Telephone Technician's license with a radar endorsement from the FCC. And like Stratele and both of us, has spen thousands of hours of bench time repairing hundreds of Fender amps and guitars.

We should all bow down and kiss his ring......

:roll:

Arjay


+100


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Post subject: Re: DRRI- solid state rectifier
Posted: Wed Apr 24, 2013 4:39 am
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yomammaaho wrote:
...Someone should make the s.s. rectifiers so that you can plug a tube in, and the diodes would only kick in if the GZ34 shorts.........saving your fuse......or tranny.


This will do exactly that. Just pick up a couple of diodes, 1N4007 or better, and wire them like this, and plug in the rectifier tube (the amp won't work without the rectifier tube). You will still get the tube sag and the diodes will only work if the rectifier tube shorts, allowing continued play until a new rectifier tube is installed, albeit with a higher B+. The diodes do not protect the rectifier tube, but will protect the amp, should the rectifier tube short. I have done this mod, and it's fairly easy to do. I couldn't find the site where I copped this picture.

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Post subject: Re: DRRI- solid state rectifier
Posted: Wed Apr 24, 2013 5:24 am
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Shimmy, it's from me. AA (Audio Asylum) site for use in Dynaco ST-70 amps which are very hard on Sovtek or Chinese made 5AR4. Only one modification to the original plan --- use UF4007 instead of 1N4007. Ultra-fast diodes have better noise stats. And are relatively cheap for good ones. I recommend good US or German made ones.


http://www.farnell.com/datasheets/57067.pdf

http://www.partsconnexion.com/rectifier ... neral.html

:D


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Post subject: Re: DRRI- solid state rectifier
Posted: Wed Apr 24, 2013 5:01 pm
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In that case, thanks very much for the link. :) I just wanted the picture to show others, as it's easier than typing an explanation.

I've never really found the need for UF in a guitar amp power supply, no noise problems as of yet. Even UF diodes still create 60/120 Hz hum that must be filtered. I can't remember coming across a guitar amp yet that the designers felt the need to use UF diodes in the power supply. The last amp that I did this to, a silver face Princeton reverb, I used ECG 125 general purpose diodes. Notice the picture lists 1N4007. But hey, it sure can't hurt to use the best diodes possible.

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Post subject: Re: DRRI- solid state rectifier
Posted: Tue May 13, 2014 8:57 am
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Hey y'all,

I'm not only new to this forum, but I'm also new to amp repair/mods etc., so please bear with me as I am truly trying to understand all this mumbo jumbo.

I've been researching solid state rectifiers and would like to try some out on my 60's-mid 70's super reverbs (I have three), but I'm having a helluva time trying to figure out which ones to start with. Is a Yellow Jacket rec a good one, or are they pretty much all the same? I can't seem to find a definitive answer.

As a 30+ year helicopter technician I have a pretty good understanding of electronics, but this amp stuff can be way over my head, especially when helo's have absolutely no tube stuff in them.

Thanks!


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Post subject: Re: DRRI- solid state rectifier
Posted: Tue May 13, 2014 9:03 am
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X-Ray Demon wrote:
As a 30+ year helicopter technician I have a pretty good understanding of electronics, but this amp stuff can be way over my head, especially when helo's have absolutely no tube stuff in them.


"Helos"?

:shock:

Must be a rust-picker.

:mrgreen:

Watch that EGT and keep your rotor in the green.

Arjay

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Post subject: Re: DRRI- solid state rectifier
Posted: Tue May 13, 2014 9:40 am
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I don't know how to quote yet, but yes Arjay, they say watch your T's & P's but we have to watch our R's (RPM'S) as well!

T's & P's ain't gonna do ya no good when your rotor's bleeding off.


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Post subject: Re: DRRI- solid state rectifier
Posted: Tue May 13, 2014 10:05 am
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X-Ray Demon wrote:
Hey y'all,

I've been researching solid state rectifiers and would like to try some out on my 60's-mid 70's super reverbs (I have three), but I'm having a helluva time trying to figure out which ones to start with. Is a Yellow Jacket rec a good one, or are they pretty much all the same? I can't seem to find a definitive answer.

Thanks!


X-ray, I would not use a Yellow Jacket or some such solid-state substitute in your Super Reverb. You will lose a lot of the sag which makes the SR such a great amp.

There are good US made NOS 5U4GB's available. This tube rectifier will work in your amp. And good ones last forever. Just rebias the amp, once you put in a new one.

My favorites are the black plate Tungsol, Raytheon, RCA, CBS-Hytron, Sylvania, and GE's. But, the US made gray plates are very good, too.

http://www.ebay.com/sch/i.html?_trksid= ... &_from=R40


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Post subject: Re: DRRI- solid state rectifier
Posted: Wed May 14, 2014 2:12 pm
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*X-ray, I would not use a Yellow Jacket or some such solid-state substitute in your Super Reverb. You will lose a lot of the sag which makes the SR such a great amp.*


Thanks, Bimmer!

You're right, I've kind of come to that same conclusion about the sag and all.

I recently bought a 1965 small bottle GE 5AR4=GZ34 rectifier with copper plates from Tube World that I want to put in my '65 SR - it had a Shuguang 5AR4 in it.

It also had some GE GT6L6's, Sovtek 12AX7's, an Electro-Harmonix 12AX7EH and some 12AT7's I can't identify. The filter caps are iffy too - the installer did a crappy job replacing them with Spragues (one which was way off on the specs) and Nichicon's.
Other than the above and the '07 & '09 Jensens, she looks pretty much untouched.

The SS rectifier business was just a thought that's pretty much out of my head now. I want to start with getting this thing all to original specs before I start messing with it. I'll mess with my '76 SR instead.

My '73 SR is completely original, from the RCA tubes, CTS alnico speakers and all the caps, etc.

With the exception of a couple (I think) tubes the '76 is all original as well.

My head is hurting just thinking about which caps to use for replacements - but first things first, so I'll concentrate on the tubes right now.

I'm also not going to play them until I have a tech look at them - just look at them, mind you. I plan on doing all the work myself - I don't trust mechanics, and an amp tech is just another mechanic to me, and I know mechanics! I have a new Fender Blues Deluxe and a '95 Bassman RI (not a LTD) I can play with in the meantime.

Anyway - thanks again for the advice.


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Post subject: Re: DRRI- solid state rectifier
Posted: Wed May 14, 2014 2:56 pm
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X-Ray Demon wrote:
I'm also not going to play them until I have a tech look at them - just look at them, mind you. I plan on doing all the work myself - I don't trust mechanics, and an amp tech is just another mechanic to me, and I know mechanics! I have a new Fender Blues Deluxe and a '95 Bassman RI (not a LTD) I can play with in the meantime.


Be prepared to pay a nominal fee for a routine bench check. My buddy in Tucson (gold-level Fender-certified for the last 25 years) routinely charges $35 for such a service. Most techs charge $50 or more.

Arjay

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Post subject: Re: DRRI- solid state rectifier
Posted: Wed May 14, 2014 9:26 pm
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X-Ray Demon wrote:
I don't know how to quote yet.


Click the "Quote" button in the lower right of the post you want to quote and then start typing.

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Post subject: Re: DRRI- solid state rectifier
Posted: Sun May 25, 2014 10:14 pm
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X-Ray Demon wrote:
Hey y'all,

I'm not only new to this forum, but I'm also new to amp repair/mods etc., so please bear with me as I am truly trying to understand all this mumbo jumbo.

I've been researching solid state rectifiers and would like to try some out on my 60's-mid 70's super reverbs (I have three), but I'm having a helluva time trying to figure out which ones to start with. Is a Yellow Jacket rec a good one, or are they pretty much all the same? I can't seem to find a definitive answer.

As a 30+ year helicopter technician I have a pretty good understanding of electronics, but this amp stuff can be way over my head, especially when helo's have absolutely no tube stuff in them.

Thanks!

Is it true that helicopters don't actually fly but instead beat the ground into submission?

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