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Old 23rd July 2013, 10:31 AM   #5321
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Default One when stationary and one when traveling

For desk use (4-5 hours/day) EL84 SE that is usually operated single-stage (input from USB soundcard straight to trioded EL84 with 98db OB speakers 1 meter away) but can be switched to 2-stage if required.

For travel, all direct-heated headphone amp that plays for some 9 hours hours on one battery charge.

If not obvious from the pictures, both were made mostly of junk parts (but the labeling on the headamp 'housing' fits quite well ...)
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Old 23rd July 2013, 10:43 AM   #5322
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Dovla,

Can you share the schematic of your headphone amp? Is it the one on picture with miniature tubes?
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Old 23rd July 2013, 10:56 AM   #5323
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Quote:
Originally Posted by yagoolar View Post
Dovla,

Can you share the schematic of your headphone amp? Is it the one on picture with miniature tubes?
Schematic is in this thread Micro amp - all-tube, direct heated, portable and IT FITS
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Old 26th July 2013, 08:13 AM   #5324
tcqanh is offline tcqanh  Viet Nam
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Quote:
Originally Posted by kevinkr View Post
Simple all transformer coupled stage design using a single GM70 and triode connected D3A per channel.
Hi Kevin,

I've heard this formula D3a-GM70 SE in my friend's system. Sound is a bit harsh, not much warm, rich tone... like traditional SET amp.

Is it enough gain for GM70 (over 200Vp-p) ?
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Old 26th July 2013, 11:21 AM   #5325
kevinkr is offline kevinkr  United States
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Mine is very pleasant to listen to without being particularly euphonic.. Actually in class A1 at 1kV about 160Vpp is all that is required.

Significantly less than 1Vrms is required to drive it to full output.

IT is 1:1

Opt is 7K:8

D3A runs at 20mA, GM70 at 120mA..

Currently using graphite plate GM70s.
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Old 27th July 2013, 01:49 AM   #5326
tcqanh is offline tcqanh  Viet Nam
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Quote:
Originally Posted by kevinkr View Post
Mine is very pleasant to listen to without being particularly euphonic.. Actually in class A1 at 1kV about 160Vpp is all that is required.

Significantly less than 1Vrms is required to drive it to full output.

IT is 1:1

Opt is 7K:8

D3A runs at 20mA, GM70 at 120mA..

Currently using graphite plate GM70s.
My system has the same formula with you: DHT pre amp --> power amp including penthode tube in triode mode- IT- power tube.
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Old 29th July 2013, 11:49 AM   #5327
AJT is offline AJT  Philippines
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shape of things to come.... 8)

EL34 PSE...
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6V6 pp amo...
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Old 29th July 2013, 12:57 PM   #5328
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Quote:
Originally Posted by tcqanh View Post
My system has the same formula with you: DHT pre amp --> power amp including penthode tube in triode mode- IT- power tube.
Hi, I have a pair of new GM70 but do not have any plan to use. Do you want to take it for free?
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Old 29th July 2013, 03:40 PM   #5329
dady is offline dady  Argentina
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Thanks god this topic doesn't disappear and I m still receiving some good impressions and news from anybody that is making something beautiful in this world. The summer now in Menorca is a fresh and clear balsamic water.
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Old 30th July 2013, 01:27 AM   #5330
tcqanh is offline tcqanh  Viet Nam
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Quote:
Originally Posted by loudnoise View Post
Hi, I have a pair of new GM70 but do not have any plan to use. Do you want to take it for free?
Just met minhhp6365 at Thivan last week, so I known you did move your home. Your 4D32 PP mono block look so nice . How is new life ?

Tks for your kind! How do I get those GM70s ?
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