What type of part is this? My amp project :)

[darren01]

Hello,

I popped open a tube amp of mine to take digital shots to use for my summer project.

There is one type of component that I am not familiar with. It is the metal, square shaped thing pictured below.

This is placed in between the power source and the tube.

Any clue? What does it do?

Thanks in advance.

Darren

[PeteMcK]

could be an ancient selenium rectifier.
How old is the amp?

Pete McK

[darren01]

Must be 1959-early 1960s.

It is an amp with an ECL82 tube in it.

What would this specific rectifyer do?

Darren

[Bill Fitzpatrick]

That is definitely a selenium rectifier. As I recall, they had a forward voltage drop of 1.4v. They have been replaced by silicon diodes.

[darren01]

Hello,

Thanks for the info.

As part of this project I want to replace all the parts that are not good. Capacitors have to go.

Should I replace this component with a new one or should it be okay?



Darren
(who knows nothing about recitfyers)

[planet10]

Originally posted by darren01
Should I replace this component with a new one or should it be okay?

Most assuridly yes... if it is just a single (half-wave rectifier)you probably want to replace it with a bridge (full-wave rectifier ie 4 x IN4007 would do)

It will have less noise & hum, and you will avoid the not that all uncommon phenomenom of the selinium rectifier depositing its guts all thru-out your amplifier.

dave

[darren01]

Thanks for your answer.

You said "full-wave rectifier ie 4 x IN4007 would do."

Do I put 4 of these in series in place of the original?

I see Digikey.com has many types of 1n4007. Which is the best to get?

Here is another part I have questions about.

It appears to be a four-in-one type of capacitor. Picture is down below.

Two out of the 5 leads go directly to the tube, one goes to ground, one to the rectifyer, and one to a resistor > tube.

It is a 60-60/40/25 mf capacitor with voltage values are 250-250/200/25.

Do I replace this capacitors with 4 equivalent Electrolytics?


Darren

[planet10]

Originally posted by darren01
You said "full-wave rectifier ie 4 x IN4007 would do."

Do I put 4 of these in series in place of the original?

Here is an article i did on a simplier, but similar amp with scematic & pictures, look at the power supply

http://www.t-linespeakers.org/tubes/SEP_50EH5.html

It is a 60-60/40/25 mf capacitor with voltage values are 250-250/200/25.

Do I replace this capacitors with 4 equivalent Electrolytics?

Yes, althou there are some places where you can get multipart elcos for restoration purposes.

Before you do anything you want to trace out the circuit (this is a very valuable learning experience)

this site will be helpful

http://tdsl.duncanamps.com/tubesearch.php



dave

[planet10]

this scematic of Morse's 6BM8 amp (there is a whole thread on it) will be roughly the same as yours (at least in terms of where things should be -- values may be different -- your amp may well have a bypass cap in the cathode of the pentode)

dave

[darren01]

Originally posted by planet10

Yes, althou there are some places where you can get multipart elcos for restoration purposes.

Hello,

Thanks, again for the replys. You are very helpful.

This isn't a restoration job. I am aiming to bring this stylish 40+ year old tube amp'ed Stereo Reel to Reel Hi-Fi system up to date.

It isn't worth more then $10 as it is. Other RtR recorders from the same era and by the same manufacturer rarely sell on eBay even when listed at $5.

Very heavy. Postage is more than the value of these things, I recon.

Originally posted by planet10

Before you do anything you want to trace out the circuit (this is a very valuable learning experience)

I tried it just now and am no good at it. I am much better at point-to-point removal and replacement soldering.

Show me a scematic and I am lost. Show me the physical finished product and I understand it.

Originally posted by planet10

this site will be helpful

http://tdsl.duncanamps.com/tubesearch.php



dave

Thanks for the tips and hints.

As stated above, I just want to bring this up to date as much as I can for the fun of it.

I got some old reel to reels. Hours worth. It would be great to be able to listen to them in better quality or even record over them in stereo.

Taking all the old capacitors out and replacing them with good audio grade or better one, replacing the recitfier and putting new plugs and jacks on it is the mission.

Basically, I am hoping for something that sounded better when bought new.

I will be posting at DIYaudio.com very often as I find the parts and progress is made.

There will also be a website. I have over 40 photos taken for it already.

Back to the rectifier thing. Do I solder all four of these in series?

Can someone show me an example of how this is done? I am ordering those parts, along with others, tomorrow afternoon.


Darren