Simple SE GU-50

[LAZAROIU]

When you point at blocking distortion when grid current occurs, the combination of coupling capacitor / high ohm-ish grid leak resistor is more responsible. Replacing the grid resistor by a low DCR grid choke should work OK, also with a coupling capacitor.
Better drive still will be there with an interstage transformer IMO.

It may get justice, but an interstage transformer is more difficult.
Semanlul asymmetric attack is just to be absolutely symmetric signal task.
Shme works perfectly with excellent results, as designed.
Certainly there is room for improvement, undoubtedly.

 

[pieter t]

....Semanlul asymmetric attack is just to be absolutely symmetric signal task....

I don't understand this sentence (apart from the fact that "lul" is "dick" in Dutch ).

 

[Einric]

WOW Guys, I'm looking for a great middle ground between Simple and Quality.

 

[Wavebourn]

WOW Guys, I'm looking for a great middle ground between Simple and Quality.

Here you go:

For more details: http://www.jogis-roehrenbude.de/Verstaerker/LS50.htm

 

[LAZAROIU]

I don't understand this sentence (apart from the fact that "lul" is "dick" in Dutch ).

Sorry, I do not speak English and try to <google translate>, if you mind do not interfere with anything here, I promise!
I know that electronics is a universal language and that schemes are sufficient ....

 

[Einric]

@ Wave,

Your schematic shows an isolated input @ 7kΩ.
Does the input need to be exactly 7kΩ?
Does it need to be isolated?

BTW, I love the simplicity of that circuit.

 

[Davec113]

Einric, I have a Simple SE running el34s in triode mode and it is enough power for my 93 dB efficient Omega single driver speakers. I can run UL too if I need more power, but I never do. So, I don't think you need to parallel tubes to get more power and there is some chance it could degrade sound quality. Good luck on the amp, I am very happy with my Simple SE.

 

[Wavebourn]

@ Wave,

Your schematic shows an isolated input @ 7kΩ.
Does the input need to be exactly 7kΩ?
Does it need to be isolated?

BTW, I love the simplicity of that circuit.

I believe that German guy that published it used some kind of available standard then transformers. Don't forget that in SE triode mode the tube needs about 30V RMS input voltage.

 

[Einric]

Well then, I should take a reading from my Aikido to see how much voltage I have on the output with 1.5-2.1V input.
Anybody know off the top of their head? 1.5V input with 9db of gain? = Output Voltage?

 

[Einric]

OK so it looks like my Aikido 6CG7-6CG7 has about 19.5db of gain not 9.5.
At 300V there is 20.7db input gain with -.9db of output gain.
This looks like about 10 volts of gain.
It looks like I will need to replace the input tubes with 12AX7's @300V to get the voltage gain I need.
Good thing I built my heater supply to be 12.6V!

 

[Einric]

So with a 12AX7 in the driver position on my Aikido I should have right around 30V of gain.
Will this be sufficient to drive a SE GU50?

What would be the best way to implement the above circuit with a 12AX7-6CG7 Aikido as the driver?

 

[Einric]

Or....Wave.....Do you have a circuit for your Gubernator that is complete and ready to build in GU50 Triode?
I can follow your schematics very well and all I will need to build is a pick list.

 

[Wavebourn]

Or....Wave.....Do you have a circuit for your Gubernator that is complete and ready to build in GU50 Triode?
I can follow your schematics very well and all I will need to build is a pick list.

I think the version on my Forum that Knarf simulated is ready to breadboard.

Here it is:

http://wavebourn.com/forum/viewtopic.php?p=25154

 

[matejsirk]

My variations on GU-50:

For my taste is the best sounding with 6J52P

 

[Einric]

All of those options look great, they are also nice because my multimeter only goes up to 600V.
I will look through them an make a decision.

Would an Edcore GXSE10-6-10K suffice for these circuits?
This would help keep the iron cost down.

How well do the 3.5K OPT's work?

 

[Einric]

Do the 6J52P valves us a standard 9-pin socket?

 

[Einric]

Wave, do you (or anybody) have an English translation of the GU50 datasheet?

 

[Einric]

Would a 6Ω secondary be OK for 4-8Ω speakers?
The speakers I will be building for this amp are 6Ω but for future purposes I'm just wondering.

 

[Wavebourn]

Wave, do you (or anybody) have an English translation of the GU50 datasheet?

No, English was language of "potential enemy".

Search for LS-50 datasheet, it is in German.

 

[Wavebourn]

Would a 6Ω secondary be OK for 4-8Ω speakers?
The speakers I will be building for this amp are 6Ω but for future purposes I'm just wondering.

Use Google Translate - we discussed this matter in that topic. It is not about speaker, it is about optimum load of the tube. Search here on the forum for load lines. GXSE10-6-10K is what doctor prescribed for Frank's schematic. However, for better bass I would use 25W Edcor transformer instead of 10K one.