Really subjective question

regal · 25th February 2010, 08:23 AM

I'm embarking on building a new tube headphone amp. I guess I've always used tubes that are known for audio. But for this amp I want to build a SE zero feedback spud type with an OPT. The 6EW7 and the 6c45pi would perform really well on paper but they aren't really classic audio tubes. My other option would be to sacrifice some power/gain and use a classic WE417A/5842.

What due you think is more important specs or classic tubes? The reason I ask is because my 6SN7 based head amp sounds 100x better with 1940's RCA's vs new tubes and my 6DJ8 headamp sounds 100x better when I use old Amperex vs newer tubes. So I am leary of the 6EW7 and 6c45pi where there are practically no tube rolling options and audiophile qualities are practically unknown.

SY · 25th February 2010, 10:09 AM

Neither. Performance in a proposed circuit is #1 for me. "Classic" is fun, no argument, but I want my boxes of gain to PERFORM.

Yvesm · 12:55 PM

I follow Stuart ... adding that neither 6C45pi nor 417 was originally designed for audio use

And that 99% of the 6SN7 production spent their live in vertically sweeping spots in B&W TV sets.

Yves.

regal · 25th February 2010, 01:09 PM

Why is the 6EW7 rarely used, seems the perfect tube to drive anything from headphones to DHTs on paper ?

Yvesm · 25th February 2010, 01:45 PM

Mmmh ...

The gain of the small triode is too low to fully drive the large one from an usual audio source.
May be a reason for its desaffection

Yves.

Glowbug · 25th February 2010, 02:18 PM

Quote:

Originally Posted by regal

I'm embarking on building a new tube headphone amp. I guess I've always used tubes that are known for audio. But for this amp I want to build a SE zero feedback spud type with an OPT. The 6EW7 and the 6c45pi would perform really well on paper but they aren't really classic audio tubes. My other option would be to sacrifice some power/gain and use a classic WE417A/5842.

What due you think is more important specs or classic tubes? The reason I ask is because my 6SN7 based head amp sounds 100x better with 1940's RCA's vs new tubes and my 6DJ8 headamp sounds 100x better when I use old Amperex vs newer tubes. So I am leary of the 6EW7 and 6c45pi where there are practically no tube rolling options and audiophile qualities are practically unknown.

One thing that's cool about DIY is the ability to use a tube that really works well in a design, that might have had nothing to do with audio originally

Besides, the "non-audiophile" tubes are cheaper, and there are boxes upon boxes of them sitting around for years to come.

Bas Horneman · 25th February 2010, 02:47 PM

Seen this 6EW7 design? I have a few 6EW7's and I'll use em one day for sure.

Attached is GLUCA's design, which he uses as a headphone amp.

regal · 26th February 2010, 10:08 AM

Quote:

Originally Posted by Bas Horneman

Seen this 6EW7 design? I have a few 6EW7's and I'll use em one day for sure.

Attached is GLUCA's design, which he uses as a headphone amp.

Cool design.

This is what I am thinking of building. I want low output impedance and high power. This puts the tube at its lowest Rp. I am on the fence with going parafeed, but I lose a lot of power. The big expensive commercial tube headphone amps all use gobs of power.

Bas Horneman · 26th February 2010, 10:40 AM

Should work like a charm!

SY · 26th February 2010, 10:50 AM

Regal, in a conventional circuit, one would AC couple between driver and output stage. This circuit eliminates that, but then AC couples the output stage. So you've removed a small (~100nF) cap from the signal path, and to do that, you then stick a big (50u) cap into the signal path. Which cap is likely to be more ideal?

25th February 2010, 10:09 AM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Neither. Performance in a proposed circuit is #1 for me. "Classic" is fun, no argument, but I want my boxes of gain to PERFORM. __________________ If there's a sucker born every minute, where do the rest of them come from?

25th February 2010, 12:52 PM	#3
Yvesm diyAudio Member Join Date: Jul 2004 Location: Ardeche	I follow Stuart ... adding that neither 6C45pi nor 417 was originally designed for audio use And that 99% of the 6SN7 production spent their live in vertically sweeping spots in B&W TV sets. Yves. Last edited by Yvesm; 25th February 2010 at 12:55 PM.

26th February 2010, 10:50 AM	#10
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Regal, in a conventional circuit, one would AC couple between driver and output stage. This circuit eliminates that, but then AC couples the output stage. So you've removed a small (~100nF) cap from the signal path, and to do that, you then stick a big (50u) cap into the signal path. Which cap is likely to be more ideal? __________________ If there's a sucker born every minute, where do the rest of them come from?

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25th February 2010, 08:23 AM	#1
regal diyAudio Member Join Date: Jan 2004 Location: MD	Really subjective question I'm embarking on building a new tube headphone amp. I guess I've always used tubes that are known for audio. But for this amp I want to build a SE zero feedback spud type with an OPT. The 6EW7 and the 6c45pi would perform really well on paper but they aren't really classic audio tubes. My other option would be to sacrifice some power/gain and use a classic WE417A/5842. What due you think is more important specs or classic tubes? The reason I ask is because my 6SN7 based head amp sounds 100x better with 1940's RCA's vs new tubes and my 6DJ8 headamp sounds 100x better when I use old Amperex vs newer tubes. So I am leary of the 6EW7 and 6c45pi where there are practically no tube rolling options and audiophile qualities are practically unknown.

25th February 2010, 01:09 PM	#4
regal diyAudio Member Join Date: Jan 2004 Location: MD	Why is the 6EW7 rarely used, seems the perfect tube to drive anything from headphones to DHTs on paper ?

25th February 2010, 01:45 PM	#5
Yvesm diyAudio Member Join Date: Jul 2004 Location: Ardeche	Mmmh ... The gain of the small triode is too low to fully drive the large one from an usual audio source. May be a reason for its desaffection Yves.

26th February 2010, 10:40 AM	#9
Bas Horneman diyAudio Moderator Emeritus Join Date: Apr 2002 Location: The Netherlands Blog Entries: 18	Should work like a charm!

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