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
Any comments here would be appreciated.
Joe
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
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
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,😉
The 27 is close to the 26 but is a DHT and requires a 5 pin socket.
No idea what it sound like...
Cheers,😉
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
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
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
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
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
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
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?
quetion 2:The tube 27and 76, anybody have compared these 2
tubes in sound quality?
Hi,
Search locally on a preamp using the #26 by Burnedfingers, you should find some links in there.
Cheers,😉
Search locally on a preamp using the #26 by Burnedfingers, you should find some links in there.
Cheers,😉
the 27 or 227 are great sounding tubes.
they perform extremely well in a MU-Stage (with 6688/7788/D3A)
check for full design (used as driver stage in my Golidav) my site www.dddac.de
good luck
doede
they perform extremely well in a MU-Stage (with 6688/7788/D3A)
check for full design (used as driver stage in my Golidav) my site www.dddac.de
good luck
doede
Update
Since I still hadn't completely given up on the #37 tube I wired in a switch and another transformer so it will allow the usage of either the #27 tube or the #37 tube at the flip of a switch to change heater voltage.
I dropped the 2 sets of 150H chokes going to the plates in favor of 50K plate resistors(all I had at the time).
I find the #27 tubes will keep up with the #26 tubes very well sonically without the hassle of batteries. The #37 tubes I first tried were very monophonic but the new set I purchased work very well and are only slightly monophonic.
The plate voltages and cathode voltages are very close, close enough to just plug, switch and play.
I have found that the #27 tube has become the favorite in my stable. It has even replace my beloved 5687.
Just my .02
J
Since I still hadn't completely given up on the #37 tube I wired in a switch and another transformer so it will allow the usage of either the #27 tube or the #37 tube at the flip of a switch to change heater voltage.
I dropped the 2 sets of 150H chokes going to the plates in favor of 50K plate resistors(all I had at the time).
I find the #27 tubes will keep up with the #26 tubes very well sonically without the hassle of batteries. The #37 tubes I first tried were very monophonic but the new set I purchased work very well and are only slightly monophonic.
The plate voltages and cathode voltages are very close, close enough to just plug, switch and play.
I have found that the #27 tube has become the favorite in my stable. It has even replace my beloved 5687.
Just my .02
J
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