#27 tube for line amp?

Original Burnedfingers · 27th October 2003, 11:31 AM

In my quest for yet another line amp project I have uncovered possibly another jewel. I found a set of #27 tubes and not being an expert like some here, the curves look very close to those of the 26. It has its pros and cons.. 1.75 amp at 2.5 volt heater for one. It should make for something interesting.

Any comments here would be appreciated.

Joe

45guy · 27th October 2003, 02:57 PM

I think it's a great sounding tube, especially the mesh plate versions. Unfortunately, most of the meshies that I have are microphonic. I picked up quite a few a couple of months ago and still don't have a great matched pair. Oh well, the solid plate varieties are pretty darn good too. I threw together something very quickly and ran them at pretty much book value. A little noisey but it was built out of scraps from previous projects and clip leads hung out the bottom. It was enough for me to know that I will be spending some time with this tube.

Have you seen this one- http://www.suertenich.com/html/schematic.gif

Cheers,
Tom

fdegrove · 27th October 2003, 03:24 PM

Hi,

The 27 is close to the 26 but is a DHT and requires a 5 pin socket.

No idea what it sound like...

Cheers,

Original Burnedfingers · 27th October 2003, 11:31 PM

Tom

Thank you very much for the link. It has a nice schematic that will be a very good place to start. I'm not getting the fancy mesh plate tubes because all my projects aren't very fancy. The tube kind of interested me so I figured what the heck. It sounds like my hopes for the 27 will be met since you like yours. The 26, what I have together of it at least sounds very good but is somewhat ill manored. The 27 sounds like it will be really close to the 26 without needing to run the heater off batterys.

Frank

I will keep you posted with the outcome of the 27 project after I finish the 26 ordeal.

Joe

45guy · 28th October 2003, 04:30 AM

Hi Joe,

This thread got me in the mood to take a crack at it again and see if I can get things quieted down some. Well, it's fairly quiet now with a low uf CLCLCLC supply. I think I have determined that anywhere you run this tube, it just sounds good. My op points were not even close while I was messing with the supply and it still sounded good at 80+ volts drawing less than 1ma. I find it interesting that the tube data says to reference the heater supply midpoint to the the cathode. I'm running them floating off a big DC supply right now but I'll try AC with the CT to the cathodes in the morning.

Good luck on the 26 project.

Tom

Original Burnedfingers · 28th October 2003, 10:24 AM

Tom

I'm glad I got you interested in the 27 again. Maybe I can talk you into posting your final schematic on the board. It will be interesting to see what it takes to make this tube behave.

Joe

Ryssen · 21st December 2003, 12:06 AM

Any one have the schema for 27,as the link is not working.
quetion 2:The tube 27and 76, anybody have compared these 2
tubes in sound quality?

fdegrove · 21st December 2003, 12:10 AM

Hi,

Quote:

Any one have the schema for 27,as the link is not working.

The Suertenich link you mean?

Cheers,

Ryssen · 21st December 2003, 12:27 AM

Yes. Or have any other?

fdegrove · 21st December 2003, 12:31 AM

Hi,

Quote:

Yes. Or have any other?

Search locally on a preamp using the #26 by Burnedfingers, you should find some links in there.

Cheers,

27th October 2003, 11:31 AM	#1
Original Burnedfingers diyAudio Member Join Date: Nov 2002	#27 tube for line amp? In my quest for yet another line amp project I have uncovered possibly another jewel. I found a set of #27 tubes and not being an expert like some here, the curves look very close to those of the 26. It has its pros and cons.. 1.75 amp at 2.5 volt heater for one. It should make for something interesting. Any comments here would be appreciated. Joe

27th October 2003, 03:24 PM	#3
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	Hi, The 27 is close to the 26 but is a DHT and requires a 5 pin socket. No idea what it sound like... Cheers, __________________ Frank

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27th October 2003, 02:57 PM	#2
45guy diyAudio Member Join Date: Mar 2003 Location: Midwest	yes, yes, the 27! I think it's a great sounding tube, especially the mesh plate versions. Unfortunately, most of the meshies that I have are microphonic. I picked up quite a few a couple of months ago and still don't have a great matched pair. Oh well, the solid plate varieties are pretty darn good too. I threw together something very quickly and ran them at pretty much book value. A little noisey but it was built out of scraps from previous projects and clip leads hung out the bottom. It was enough for me to know that I will be spending some time with this tube. Have you seen this one- http://www.suertenich.com/html/schematic.gif Cheers, Tom

27th October 2003, 11:31 PM	#4
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Tom Thank you very much for the link. It has a nice schematic that will be a very good place to start. I'm not getting the fancy mesh plate tubes because all my projects aren't very fancy. The tube kind of interested me so I figured what the heck. It sounds like my hopes for the 27 will be met since you like yours. The 26, what I have together of it at least sounds very good but is somewhat ill manored. The 27 sounds like it will be really close to the 26 without needing to run the heater off batterys. Frank I will keep you posted with the outcome of the 27 project after I finish the 26 ordeal. Joe

28th October 2003, 04:30 AM	#5
45guy diyAudio Member Join Date: Mar 2003 Location: Midwest	Hi Joe, This thread got me in the mood to take a crack at it again and see if I can get things quieted down some. Well, it's fairly quiet now with a low uf CLCLCLC supply. I think I have determined that anywhere you run this tube, it just sounds good. My op points were not even close while I was messing with the supply and it still sounded good at 80+ volts drawing less than 1ma. I find it interesting that the tube data says to reference the heater supply midpoint to the the cathode. I'm running them floating off a big DC supply right now but I'll try AC with the CT to the cathodes in the morning. Good luck on the 26 project. Tom

28th October 2003, 10:24 AM	#6
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Tom I'm glad I got you interested in the 27 again. Maybe I can talk you into posting your final schematic on the board. It will be interesting to see what it takes to make this tube behave. Joe

21st December 2003, 12:06 AM	#7
Ryssen diyAudio Member Join Date: Dec 2003 Location: Sweden--> Here	Any one have the schema for 27,as the link is not working. quetion 2:The tube 27and 76, anybody have compared these 2 tubes in sound quality?

21st December 2003, 12:27 AM	#9
Ryssen diyAudio Member Join Date: Dec 2003 Location: Sweden--> Here	Yes. Or have any other?

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