#26 lineamp vers a 5687 which is best? - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 29th January 2003, 11:15 AM   #1
diyAudio Member
 
Join Date: Nov 2002
Default #26 lineamp vers a 5687 which is best?

What would be the best lineamp for the money? What sonic benefits would there be to a specific tube here? Which is easiest to build?


Joe
  Reply With Quote
Old 29th January 2003, 11:52 AM   #2
7N7 is offline 7N7  United Kingdom
diyAudio Member
 
7N7's Avatar
 
Join Date: Jan 2003
Location: England
Default Re: #26 lineamp vers a 5687 which is best?

Quote:
Originally posted by burnedfingers
What would be the best lineamp for the money? What sonic benefits would there be to a specific tube here? Which is easiest to build?


Joe
As I recall, a 26 is a directly-heated version of the 27, a 2.5v triode, with mu of about 9.

5687's mu is said to be 15, although this does depend to a certain extent on the amount of current passed. c And of course it is a double triode

There would be a considerable difference.

Personally I could not imagine driving a line with a 26 as I think that like its successors, 27 and 37 that it would be a little weedy for this service.

Much depends on how much gain you need.

My preference in this sort of area would be for a 6BL7 (octal double triode, mu = 15).

In fact I am using a couple of these in my own line stage at present and 6BL7 is quite happy driving 15 feet of balanced line.

7N7
__________________
Plug them in and light them up
  Reply With Quote
Old 29th January 2003, 02:37 PM   #3
Joel is offline Joel  United States
diyAudio Member
 
Joel's Avatar
 
Join Date: Oct 2002
Location: Brooklyn, NY
Joe, I assume you fixed the other preamp project? No hum?
  Reply With Quote
Old 30th January 2003, 01:44 AM   #4
diyAudio Member
 
Join Date: Nov 2002
Joel and 7N7

Actually I plan to have a collection of lineamps all of which exhibit severe hum problems. JUST KIDDING!!!! Problem solved by poking around with a piece of dowel rod.

Actually the #26 tube is supposed to be really sweet sounding from what I hear.

I found that with the 6SN7 lineamp I barely have the volume control cracked open at all. No, I really don't need that much gain with speakers that are in excess of 102 db 1w 1m.

I plan to build both the 5687 and the #26 lineamp as I have tubes for both. Running for cover now and hiding my #26 tubes from the Antique radio rebuilders.

Joe
  Reply With Quote
Old 30th January 2003, 12:14 PM   #5
7N7 is offline 7N7  United Kingdom
diyAudio Member
 
7N7's Avatar
 
Join Date: Jan 2003
Location: England
Actually the #26 tube is supposed to be really sweet sounding from what I hear.

I found that with the 6SN7 lineamp I barely have the volume control cracked open at all. No, I really don't need that much gain with speakers that are in excess of 102 db 1w 1m.





Sweet-sounding or not, you still have to drive a cable I presume? I cannot imagine 26 driving anything except a cathode follower - your best option in a line stage.

Run your 26s into your 6SN7 configured as a self biased cathode follower - or DC coupled if you have the HT available; that should sound good - and will have very good distortion performance.

If you are getting that much gain with 6SN7 (typical gain about 15), then perhaps your power amplifiers are too sensitive?

If you do not wish to use the cathode followers, this sounds like a job for 12B4 (mu=6), 6BX7, or the beefy half of a dissimilar triode: 6EW7 would be a good choice.

7N7
__________________
Plug them in and light them up
  Reply With Quote
Old 30th January 2003, 12:22 PM   #6
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default DISSIMILAR TRIODES.

Hi,

There's a host of dissimilar triodes such as the 6EM7,6DR7,6EW7 and so on out there that lend themselves nicely for preamp+headphone amp.

Most of them contain a low power medium mu triode + a high power (~ 10W) low mu triode.

Use one as an anode follower,the other as a CF and bingo,you're done.

Cheers,
__________________
Frank
  Reply With Quote
Old 30th January 2003, 01:34 PM   #7
Joel is offline Joel  United States
diyAudio Member
 
Joel's Avatar
 
Join Date: Oct 2002
Location: Brooklyn, NY
Quote:
Originally posted by burnedfingers
I found that with the 6SN7 lineamp I barely have the volume control cracked open at all. No, I really don't need that much gain with speakers that are in excess of 102db
Hey Joe,
That's exactly what I found to be the case. The extra gain from the 12AY7 really only came into play when using 63 ohm headphones. Then I regularly had the volume set to one o'clock.

RE: 26
That's a DHT, so there's no easy way to do a cathode follower output... you're going to have a high output impedance. Keep the cables very short, and make sure the power amp has an input of at least 100k.

I went through this whole phase a while back, and I realized that in order to give the preamp a reason for living, all or some of my DIY power amps would need to be weak on gain - ie. very low input sensitivities on the order of 8 volts.
It just doesn't seem like it's worth the extra wire and possible degradation.

If I were you, I'd take your beloved 26 and make it the front end of a new poweramp. And, if you've got 102db speakers, your possiblities are wide open. You could even build a 71 SE!
  Reply With Quote
Old 30th January 2003, 02:17 PM   #8
7N7 is offline 7N7  United Kingdom
diyAudio Member
 
7N7's Avatar
 
Join Date: Jan 2003
Location: England
Quote:
Originally posted by Joel


RE: 26
That's a DHT, so there's no easy way to do a cathode follower output... you're going to have a high output impedance. Keep the cables very short, and make sure the power amp has an input of at least 100k.

I
I suggested that he DC couple the 26s' anodes to a 6SN7; surely there can be no problem with that?



7N7
__________________
Plug them in and light them up
  Reply With Quote
Old 30th January 2003, 02:25 PM   #9
Joel is offline Joel  United States
diyAudio Member
 
Joel's Avatar
 
Join Date: Oct 2002
Location: Brooklyn, NY
7N7, I meant if he planned on using 26's solely.
  Reply With Quote
Old 30th January 2003, 02:28 PM   #10
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default HMMMM...

Hi,

Quote:
That's a DHT, so there's no easy way to do a cathode follower output...
Doesn't make sense to me either?
Or did you mean turning the 26 into a CF?

Cheers,
__________________
Frank
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Vers 2x-Next remake bl3nd3r Full Range 3 12th June 2009 07:19 PM
5687 dc 5687 tube amp need help vangogh-hk Tubes / Valves 8 4th January 2006 12:09 AM
Gainclone vers the A40 board Original Burnedfingers Everything Else 1 18th December 2005 12:38 PM
TL074 vers. TL084 ? lohk Solid State 17 20th January 2003 12:37 PM


New To Site? Need Help?

All times are GMT. The time now is 04:47 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2