• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

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No, unfortunately, I haven’t tried swapping caps. I know many people enjoy parts rolling but I’m content if the gear comes out looking ok and sounds half-decent. I realize I’m a pathetic audiophile, but it’s one less thing to give me anxiety.

Rolling or not rolling parts has nothing to do with being an audiophile or not.
 
Here is my latest build, GU-46 single ended stereo amplifier.
Power management (start up and shut down) by Siemens Logo 8 aequivalent.
Currently with with a 12hg7 driver installed (might be changed to some other tube later).
4 5C8S rectifier tubes per channel.
Circuit optimization ongoing.
Total weight of iron approx. 90kg, capacitors and electronics approx. 12kg, industrial aluminium profile housing and lexan/plexy approx. 55kg

wowww impressive also you really take care of small details on the looks, is very easy for massive structure compromise the looks but you certainly did a very impressive good job, simple and linear looking but very classy and "handsome", may I ask you how long it takes you for build it and how it sound? Can you also include some technical details like frequency response, max power and THD? Best Regards
 
I found some time to finalize the details on an amp that is playing for a while. Push pull, classA, 7W with EF80, 6P31S. The looks maybe so and so because cost was an object, but the sound is marvelous.
 

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Just finished my latest project. A 45 single ended amp with 2 24A triode strapped tubes in the preamp.

All cloth wire and cable laced point to point wiring.
Very, very interesting!
Would you mind share the scheme and your sound impressions?
I'd like to build one too, and maybe with an option to use 46 tubes as well (like the old "Ragtop" amp).
Thank you in advance!
 
what a beauty! love that nice wiring loom and I didn't know they made those Russian caps in such a pretty colour :) Do you happen to have more pictures

Thank you! Of course there are more pictures ;)

As far as I know the only russan PIO caps that come in that nice blue colour are the 250nF 630V ones.

Very, very interesting!
Would you mind share the scheme and your sound impressions?
I'd like to build one too, and maybe with an option to use 46 tubes as well (like the old "Ragtop" amp).
Thank you in advance!

The circuit is really very simple. The 24A screen grids are connected to the anode with 100 ohm resistors and biased at 2.5mA and 100V, I have attached the tube curves below so you can see. The 45s are biased at 33mA and 250V with a 6K load giving about 1.3Watts.

The preamp tubes are really nice but nobody ever uses them. They are very linear as you can see in the curves, and plentiful and cheap. The biggest downside is the high heater current.
 

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First ever tube circuit!

So I became interested in Valves/Tubes a long time ago, but never got much further than drawing a load line.

I finished a first ever tube circuit this week. A very simple textbook cathode biased voltage amplifier stage.

Using a load line I get fairly close to reality, biasing voltage isn't quite right, and the cathode bypassing capacitor isn't large enough, but it functions fairly well.

Near to centre bias I get a voltage gain of around 41 times, which isn't too far shy of the 2/3rds Mu (mu is 70).

A great little circuit built in 15mins! I'm hooked!
 

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So I became interested in Valves/Tubes a long time ago, but never got much further than drawing a load line.

I finished a first ever tube circuit this week. A very simple textbook cathode biased voltage amplifier stage.

Using a load line I get fairly close to reality, biasing voltage isn't quite right, and the cathode bypassing capacitor isn't large enough, but it functions fairly well.

Near to centre bias I get a voltage gain of around 41 times, which isn't too far shy of the 2/3rds Mu (mu is 70).

A great little circuit built in 15mins! I'm hooked!

I have the same powersupply laying around, I believe you can even modify it to give you a negative voltage by just adding a diode and a capacitor
 
I have the same powersupply laying around, I believe you can even modify it to give you a negative voltage by just adding a diode and a capacitor

I have a couple, and I believe you are correct, just the fly back diode, output capacitor and a couple of and resistors need soldering.

(However, I blew the diode quite quickly and required a replacement)