Nina Mu Stage Preamp - Circuit and Details - Page 3

TheGimp · 27th January 2010, 02:36 PM

If you are running a Single Ended output, maybe. If you are running Push Pull, no you will need a phase splitter.

Most EL34 guitar amps are PP.

What are you hoping to build?

How much power?

Etc?

davew · 27th January 2010, 02:41 PM

Thanks for the quick reply, I am hoping to build a single ended EL34 stereo amp.

davew · 27th January 2010, 03:28 PM

Sorry I never mentioned wattage, I am hoping to get 5+ watts from the final amp. My goal is more a first hifi starter project with parts that are reasonably to hand. If I use the Nina preamp I have all the valves that I need.

Wavebourn · 27th January 2010, 04:12 PM

Quote:

Originally Posted by Mike C

When I started this project, my wife Janet said she didn't know why I was bothering as she didn't think it was possible to improve on what I had.
I wasn't too sure myself to be honest. Anyway, Janet is now convinced.

Hmmm... Who is Nina, if wife's name is Janet?

davew · 28th January 2010, 10:03 PM

I had in mind something along the lines of the output stage of this design using the nina preamp instead of the 6sl7. I would welcome any comments as to the practicality of this idea.

Stereo Single-Ended EL34 Hi-Fi Amplifier

KOMA-Cable · 17th March 2012, 01:22 PM

Hi Mike.

Long time no see on DIYaudio. Are you still alive?

I am about to built up your NINA preamp. For a better stereo separation, I want to use one E80CC for each channel, and run both E80CC-triodes in parallel-mode. Besides the better stereo separation, it will also halve the noise, and double the output current.

Now I need your help. Do I have to change any resistor-value, if I run them in parallell?

This question also goes out to all other DIY members who are interested.

Kind regards,
Max

TheGimp · 18th March 2012, 02:59 AM

davew,

If you want to run EL34 SE triode mode you will bias around -12.2V. and you don't want to go beyond -1.3V on g1 according to the data sheet (300V B+).

Given this, you only need 10.9V peak to drive it. (Pretty easy drive).

The proposed circuit should meet this requirement without difficulty.

I haven't looked at gin of the input, but yo will need considerably less than a gain of 10 to drive it from a typical line output.

17th March 2012, 01:22 PM	#26
KOMA-Cable diyAudio Member Join Date: Sep 2004 Location: Southern Austria	E80CC in parallell mode Hi Mike. Long time no see on DIYaudio. Are you still alive? I am about to built up your NINA preamp. For a better stereo separation, I want to use one E80CC for each channel, and run both E80CC-triodes in parallel-mode. Besides the better stereo separation, it will also halve the noise, and double the output current. Now I need your help. Do I have to change any resistor-value, if I run them in parallell? This question also goes out to all other DIY members who are interested. Kind regards, Max

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27th January 2010, 02:36 PM	#21
TheGimp diyAudio Member Join Date: Aug 2009 Location: Johnson City, TN	If you are running a Single Ended output, maybe. If you are running Push Pull, no you will need a phase splitter. Most EL34 guitar amps are PP. What are you hoping to build? How much power? Etc?

27th January 2010, 02:41 PM	#22
davew diyAudio Member Join Date: Nov 2006	Thanks for the quick reply, I am hoping to build a single ended EL34 stereo amp.

27th January 2010, 03:28 PM	#23
davew diyAudio Member Join Date: Nov 2006	Sorry I never mentioned wattage, I am hoping to get 5+ watts from the final amp. My goal is more a first hifi starter project with parts that are reasonably to hand. If I use the Nina preamp I have all the valves that I need.

28th January 2010, 10:03 PM	#25
davew diyAudio Member Join Date: Nov 2006	I had in mind something along the lines of the output stage of this design using the nina preamp instead of the 6sl7. I would welcome any comments as to the practicality of this idea. Stereo Single-Ended EL34 Hi-Fi Amplifier

18th March 2012, 02:59 AM	#27
TheGimp diyAudio Member Join Date: Aug 2009 Location: Johnson City, TN	davew, If you want to run EL34 SE triode mode you will bias around -12.2V. and you don't want to go beyond -1.3V on g1 according to the data sheet (300V B+). Given this, you only need 10.9V peak to drive it. (Pretty easy drive). The proposed circuit should meet this requirement without difficulty. I haven't looked at gin of the input, but yo will need considerably less than a gain of 10 to drive it from a typical line output.

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