6LU8 Spud - Request for comments

[tomchr]

Can you tell me the test equipment you have used to measure and plot the distortion vs. frequency results ?

I use an HP 8903A Audio Analyzer along with some MATLAB scripts that I developed. You can find some of them on my home page (which is in serious need of an update!!).

Beautiful amp Tom. [...]
I have doubts the CXSE25... will be much better than the GXSE10... For more correct flux in the core, the OT should be sized accordingly and an oversized ditto may not always give the best results.

Thanks! I haven't tried the GXSE. I don't think they were even available when I first designed my amp. Might be wrong, though... I did try the bigger CXSE and noticed a sizable improvement in sound quality. Unfortunately, I don't have measurement data to back that up, though.

I am just now getting ready to wire mine up. Here are some pix. I am still trying to find an Oil Pressure gauge and Oil Temp gauge for the two holes in front.

Dude!! I suggest naming that amp WTF!! or something! Cool shop amp for sure! Love the idea of oil pressure and temp gauges... even if they are wired to show B+ and bias.

~Tom

 

[djn]

Thanks Tom. I am going with the AK schematic with a couple tweeks. The OTs are from a consol of some sort but will work well.

 

[Tubelab_com]

Love the idea of oil pressure and temp gauges...

Everybody knows that you need a boost gauge!

I got mine (and other cheap gauges) from the JC Witney catalog. I stuck the boost gauge in a car though. Boost is like B+, too much makes things blow up. Expensive things!

I did try the bigger CXSE and noticed a sizable improvement in sound quality.

I came to the same conclusion. My CXSE's are currently in a 300B amp. Best sounding $100 transformers that I have found. The little XSE's sound great driven by a trioded 6V6. 2 WPC, full power down to 25 Hz.

 

[SemperFi]

Great looking amp Tom. I am just now getting ready to wire mine up. Here are some pix. I am still trying to find an Oil Pressure gauge and Oil Temp gauge for the two holes in front.

Man I like your artistic approach

 

[djn]

Everybody knows that you need a boost gauge!

I got mine (and other cheap gauges) from the JC Witney catalog. I stuck the boost gauge in a car though. Boost is like B+, too much makes things blow up. Expensive things!
.

Yep, I use to blow up my 1000cc Norton with turbo drag racing about twice a season. Love the sound of connecting rods letting loose. Then I know the motor is giving me all it's got.

Man I like your artistic approach

Thanks Semper. The art is the best part of DIY....for me at least.