Does anyone have a set of circuit boards for a #124 build?

[Joost]

I am looking for a set of circuit boards for my 124 build. I thought I could get the set at agbamplifiers, but those boards are for later builds with different power board, etc.

Does anyone have a good set of boards for sale for me, specifically for a 124 AND classic power filter board?

Does anyone know if the standard 100W ODS boards from Nik are a good match?

[Structo]

They really are simple to make.

Eyelet boards are a piece of cake.

Get some 1/8" Garolite G10.
1/8" eyelets

Here are some drawings I made when I built mine.

I think they print out 1:1

[dreric]

Here's a link to a thread I started which contrasts two simultaneous builds. At 102 (very close to 124) and a Bluesmaster. The 102 has home made boards the blues has Jason's boards except for the main and HRM. I haven't had the time to work on these in a while..............but that will change soon.


https://tubeamparchive.com/viewtopic.ph ... 89&start=0

The layouts Structo supplied will work fine. For the PS board you'll have to use the f&t or IC caps due to their smaller size.

rj, a member here offer his version of the 124 and it comes with boards. Look carefully, as rj does put his own spin on things.

http://www.rjguitars.net/Amp_Kits.html

Hope this helps

Eric

[David Root]

Jason's boards are excellent, I stocked up a while ago.

[hans-jörg]

Hi,
sorry for this shot,
but I see on Toms Layout 220K/150k as anode resistors on both channels instead of 100k trough out. Probably the Kathodes aren`t 1k5 too.
Instaed of the classic layout. Whats the effect to the current at the stages?

Hans-Jörg

[Structo]

Yes my board has high plate resistors and cathodes.

I am just showing it for parts layout.

You can certainly use 100K plates and 1K5 cathodes.

[hans-jörg]

Ok,
thats High plate! I wondered allway wath means "high plate/low plate". I had some ideas, but now its nailed.

But may I ask whats the different in tone?

Thank you Tom

Hans-Jörg

[Structo]

Amps like #124 and earlier amps used 100K plate load resistors.

The plate load and cathode resistors are chosen to determine the biasing of the preamp triode.
Generally a 100K plate resistor and a 1K5 cathode resistor will bias the triode in the center of it's designed operation producing a cleaner tone.

The higher plate load and cathode resistors bias the tube a little hotter making a harder or brighter tone.

It gets into load line plotting and all that which I'm not very good at.

I have only built and played high plate amps so I can't tell you personally how high plate and low plate differ in sound or tone.

Here is an excellent resource:
http://www.freewebs.com/valvewizard1/gainstage.html

Merlin has a book out on Preamp design that is very good and well written.
That pdf file is the first chapter in his book.
Not sure if it is available in your location but this is the book.
He also has one for power supplies.
http://www.amazon.com/Designing-Tube-Pr ... 0956154506