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My newest amp creation

#21
I own enough tools and equipment for three of four people. Electronics, carpentry, HVAC, mechanics, plumbing, electrical, painting... When I can't find something the best way to locate it is to start putting things where they belong and I eventually find the missing tool. Sometimes Ive had to find something in my enormous tool storage area, and someone is with me, and I go to the spot in all the clutter, and find it instantly, and I get asked how I knew where that tool was among all this stuff, and I reply that "I am a master of organization".:D

Question: How many tape measures, and caulk guns do you need to own so that when you need one you can find one without too much looking around?

Tape measures? Twenty, at least. Caulk guns? eight, or more.
 
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#22
REV said:
As a kid with no money one of my first amps was a Bogen PA amp that I found. It had six sixL6 power tubes I got a old Alembic F2B preamp for cheap and I was off and running. It was a great sounding setup but hard to move around. The Bogen wasn't really set up to be put in a case so I just kept it on the floor and put the F2B on top of my speaker.
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My first PA was a Bogen that my Dad pulled out of a dumpster. I plugged it in and it worked fine. I ended up selling it and then my uncle gave me a Kasino four-channel PA with reverb. This was back in the seventies.I thought I was a lucky SOB.
 
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#25
Hoochie Coochie Man said:
I own enough tools and equipment for three of four people. Electronics, carpentry, HVAC, mechanics, plumbing, electrical, painting... When I can't find something the best way to locate it is to start putting things where they belong and I eventually find the missing tool. Sometimes Ive had to find something in my enormous tool storage area, and someone is with me, and I go to the spot in all the clutter, and find it instantly, and I get asked how I knew where that tool was among all this stuff, and I reply that "I am a master of organization".:D

Question: How many tape measures, and caulk guns do you need to own so that when you need one you can find one without too much looking around?

Tape measures? Twenty, at least. Caulk guns? eight, or more.
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That’s a trick question. I don’t know how many I have. Last time I needed a caulking gun I bought a new one. The others are in deep storage and it would have broke my back to pull one out. Then there’s metric and imperial tape measures.
 
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#27
beans-on-toast said:
That’s a trick question. I don’t know how many I have. Last time I needed a caulking gun I bought a new one. The others are in deep storage and it would have broke my back to pull one out. Then there’s metric and imperial tape measures.
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One time when I needed a caulking gun and could not find one, I also gave up and just went and bought one. I bought the most expensive one they had thinking that if I paid so much for it, I would be less likely to lose track of it. I now own at least three of the most expensive ones they sell.
 
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#31
Hoochie Coochie Man, did you ever locate a schematic for your Rauland 2135? I just found an amp along with a similar 2175 amp. Both appear the same except one uses a 5Y3 for the EL34 bias circuit.
If you have a schematic for either one is it possible to get a copy?
 

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#32
5Y4 would be a very odd choice for a bias rectifier. I can’t say that I have ever seen one used that way, and I’m not sure how well it would even work if at all.
 
#34
Agedhorse, It’s not difficult to use a tube rectifier in a bias circuit, but it is impractical. You need a whole separate winding for it. It’s so much easier to use a IN4007 diode. Pictured is the power supply with bias from a print schematic of a Rauland 1960 PA from the 1950s that uses the 5Y3 for bias.
 

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#35
Jonathan horne said:
Agedhorse, It’s not difficult to use a tube rectifier in a bias circuit, but it is impractical. You need a whole separate winding for it. It’s so much easier to use a IN4007 diode. Pictured is the power supply with bias from a print schematic of a Rauland 1960 PA from the 1950s that uses the 5Y3 for bias.
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Never seen that before, the challenge is that changing the rectifier tube or the failure or degradation of the tube will cause the bias voltage to shift resulting in possible runaway saturation of the output tubes.

The more common way to do it back then was via cathode bias, then selenium rectifiers for that reason. Selenium and Ge/Si rectifiers are much more reliable and have a constant voltage drop which is much more stable.
 
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#37
Some of the Rauland amps had two 5U4GB and two 5Y3 rectifier tubes.

I’ve seen some where each power tube had it’s own bias circuit. When doing this, the bias adjustments should be independent. Adjusting one bias shouldn’t affect the other. There are ways to do this without having separate bias power supplies. But some of the Rauland PA amps date back to the 1930’s and on. Things were done differently. On the other hand, some were military and perhaps they wanted some form of redundancy. A lot were PA amps.
 
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