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ja2dhc 10th May 2008 09:28 AM

Pete's SE E-Linear
 
2 Attachment(s)
I have completed to make an E-Linear Amp based on Pete's design with my modification.

The sonic is very vivid. I have never heard such a atmosphere made by the amp.

I have up-loaded the measured results into my Web as below (sorry in Japanese) .

http://ja1cty.servehttp.com/E-LINEAR/

Many thanks to Pete to give me good suggestions.

oldeurope 10th May 2008 01:06 PM

Re: Pete's SE E-Linear
 
Hi ja2dhc,
thanks for posting the schematic.
http://ja1cty.servehttp.com/E-LINEAR/E-Linear-amp.jpg
You should make the C3g anode floating on the cathode signal
like it is done in e.g. Loftin White.

Kind regards,
Darius

ja2dhc 11th May 2008 03:17 AM

Re: Re: Pete's SE E-Linear
 
Quote:

Originally posted by oldeurope
You should make the C3g anode floating on the cathode signal
like it is done in e.g. Loftin White.
I cannot understand your point. What is the benefit ?

oldeurope 11th May 2008 08:57 AM

Re: Re: Re: Pete's SE E-Linear
 
Quote:

Originally posted by ja2dhc


I cannot understand your point. What is the benefit ?

Hello ja2dhc,
have a look at the upper 70F . Signal voltage drop at this cap causes
a signal voltage drop at the 500R resistor (cathode EL34).
This drop is deducted from the grid-cathode signal voltage.
Look how Loftin White solved this "problem".
The drive signal voltage for the power tube floates on the cathode
potential of the power tube. Very clever, isn't it?

Kind regards,
Darius

PS: In the WE (repeater amp) they made the secondary of the input transformer floating.

ja2dhc 11th May 2008 11:04 AM

Re: Re: Re: Re: Pete's SE E-Linear
 
Hi, oldeurope !

Now, I have understood your point. It's good idea .

Thanks so much for your quick response.

oldeurope 12th May 2008 10:04 AM

Hello ja2dhc,
thanks, I am happy to help you.

Best wishes,
Darius :)

pieroh 16th May 2008 01:01 PM

Quote:

Originally posted by oldeurope
Hello ja2dhc,
thanks, I am happy to help you.

Best wishes,
Darius :)

Hi Darius,
I found this thread on my search for a C3g application. I want to use this tube as a driver in a 2A3-amp. The circuit could be quite similar to the one ja2dhc uses.

You recommend to "make the C3g anode floating on the cathode signal".
I had a look at your very interesting website but I must confess, that I did not understand everything immediately.

If we stay with the given supply voltages and RC-coupling between driver and power stage, how would the practical approach look like in the circuit ja2dhc shared with us?

regards
pieroh

Sheldon 16th May 2008 05:54 PM

Hi Darius,

Nice concepts. There is something pleasing about the idea of direct coupling. Your blogs are interesting; makes me wish I had kept up with my German. One question: You mention the lack of cathode decoupling capacitors, but isn't C2 still a cathode decoupling capacitor?

Sheldon

oldeurope 16th May 2008 06:40 PM

Chb
 
Quote:

Originally #7 posted by pieroh

Hi Darius,
... The circuit could be quite similar to the one ja2dhc uses.

You recommend to "make the C3g anode floating on the cathode signal".
I had a look at your very interesting website but I must confess, that I did not understand everything immediately.

If we stay with the given supply voltages and RC-coupling between driver and power stage, how would the practical approach look like in the circuit ja2dhc shared with us?

regards
pieroh

Hello pieroh,
A practical approach is given by Loftin White.
Chb makes the driving signal floating on the cathode of the output triode.
This is one of the unknown secrets in the Loftin White topology.

Kind regards,
Darius

oldeurope 16th May 2008 06:56 PM

C2 and Chb
 
Quote:

Originally #8 posted by Sheldon
Hi Darius,
... One question: You mention the lack of cathode decoupling capacitors, but isn't C2 still a cathode decoupling capacitor?

Sheldon

Hello Sheldon,
cathode cap to ground is forbidden in a Loftin White.
If you make a bypass capacitor parallel the cathode resistor,
Chb will not be able to eliminate the losses of C2.

Kind regards,
Darius


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