Thanks,If the 34 give you 20 volt more (p.e.) the increment of the dissipation will be not so much.
Note the original Kegger amp had a lower B+ for use with an EL34. You would definitely have to adjust some things to use an EL34.Thanks,
Would using an EL34 require any adjustments?
The diagram states you can exchange no problem, including a number of others, but with my voltage readings I think increasing cathode resistor to 560R - 600R would be more suitable.
Maybe, even adding a switch between 500R for KT88 and 600R for EL34?
So in another words: no you haven't built nor have you listened to one, and I can assume you didn't watch the videos showing the measured performance of the finished amplifier either. As far as "hands on", I'm going to listen to folks that have actually put their hands on one building and testing it, rather than speculation. I understand that you like to discount the value of other people's efforts/work, I'm not sure that really does anything positive for our community/hobby.Kegger Blueglow Amplifier Analysis
Kegger Blueglow Amplifier Analysis
This amplifier is simply another member of a common 2-stage singled ended configuration...
Just to clarify the facts, what you posted isn't the Blueglow KT88 amplifier. None of the voltages match what he published, and this is a great example of what happens when someone doing an "analysis" of something, does so with a bias going into it looking to prove a statement they previously made.That should result in a very interesting distortion family.
The end result, pick whatever flavor of distortion you like....
Also, to add to the measured performance of this 'All show no GO' amp, it sounds excellent.Just to clarify the facts, what you posted isn't the Blueglow KT88 amplifier. None of the voltages match what he published, and this is a great example of what happens when someone doing an "analysis" of something, does so with a bias going into it looking to prove a statement they previously made.
Attached is the actual schematic with measured voltages off the physical amplifier, not some simulation. Also he explains to only use a ecc85 or a 6n1p at the voltages he is running for a driver and how this improves the amp in his video series, and what to do to run the other tubes listed, but that doing so increases the distortion and the amp doesn't sound as good. Also the voltages on the published schematic output tubes are for a KT88 which he also explains in the video series. Again, this "analysis" is using the wrong tubes at different voltages from what a Blueglow KT88 amp is.
I'm sure I can take any amplifier design ever made, and start changing tubes and voltages to get it to sim however badly I wanted it to be.
And FYI the actual distortion numbers of a sample of this amp, running the right tubes at the correct voltages, measured at 1% distortion is making 8W, at 5W is at 0.5% and at 10W it's still under 2%. For a SE amp those are really good numbers, the frequency response is flat and it has a lovely looking square wave. He explains all this in these two videos.
I just wanted to clarify what the measured performance on this "All show no GO" labeled amplifier actually is.
Also to the OP, clearly the voltage increase using the 5AR4 you are talking about is right at the voltages shown for this amp and shouldn't be an issue at all if built to this schematic. As always though, check your voltages!
View attachment 1074332
View attachment 1074333
Also, to add to the measured performance of this 'All show no GO' amp, it sounds excellent.
Indeed, the additional voltage will be at close to those measured by Mark. My B+ with 5U4G is 435v (at the 200uf cap, Mark's is 460v) and 425v at the KT88 plate (Mark's is 450v). So 25v difference between 5U4gb and 5AR4. My secondaries are 750v CT, 375-0-375v so a little less than Mark's Edcor
My circuit is exactly the same, with the only exception of the 5U4gb (of course) and my driver bias LED is IR not red.
Cathode voltage on my 6n1p is 2.5v, KT88 is 41v.
Kegger Blueglow Amp
How does this one differ from yours? Of the many alternative output tubes listed I simply plugged in a 6L6GC. For the driver I used a 6BK7, what did you use? On the Kegger schematic the implication is that any combination of all the tubes they listed are OK. With cathode biasing that is to an extent possible...
SE KT88 well into Class AB with 460V supply running 80 mA into 5K Loadline.
10V drop in the OPT.
wow! this is a very interesting analysis of the circuit gentleman. Good for you, the load lines start to tell an intersting story. It does beg the question; why does it get such good reviews by DIY builders? and what would the operating points be to get the best potential from the circuit? ie reasonble power and low distortion.
Thanks for your input