Suggestions for Tube Amplifier - 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 22nd August 2005, 02:57 PM   #1
diyAudio Member
 
Rundmaus's Avatar
 
Join Date: Aug 2005
Default Suggestions for Tube Amplifier

Hi,

this is my first post in the Diyaudio forum, and I'd like to ask you for a little brainstorming . I'm not totally new in this hobby, already built the Zen Amp an the Bride of Zen preamp, and a pair of transmission line speakers. But my experiences with tube technology are up to now only repairing vintage radios from the fifties or so.

A few weeks ago I got hold of the AudioValve PCL805 headphone amplifier, and now i seem to be infected with the tube virus ...

Well, here are my rough ideas, i would like to hear your suggestions, if possible accompanied by schematics ...

- PP-Design operating in Class A

- Triode output stage

- "common" tubes, please no "exotics" which are difficult to replace

- 10 to 20 watts output power per channel

- "common" output transformer, something i can buy instead of building it myself

- and, i would like to do completely without semiconductors, so i need a rectifier tube vor the anode voltage, and AC heating for all tubes

Well, i'm looking forward to your suggestions, and sorry for my English

Greetings,
Andreas
  Reply With Quote
Old 22nd August 2005, 03:09 PM   #2
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Something PP EL34 or PP EL84 comes to mind.
Here is a good start for a schematic.
Click the image to open in full size.
sorry...has semiconductors in there...but....


Plenty of choice for standard output transformers.

What preamplifier do you have? (Bride of Zen? what is the gain of that preamp?) What speakers do you have? How big is your room?

Regards,
Bas


ps..your english is perfect.
  Reply With Quote
Old 22nd August 2005, 03:21 PM   #3
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Another one
Click the image to open in full size.
http://audiotropic.netfirms.com/Projects/mmAudio.html
  Reply With Quote
Old 22nd August 2005, 03:21 PM   #4
diyAudio Member
 
Rundmaus's Avatar
 
Join Date: Aug 2005
Hi Bas,

no separate Preamp, so a preamp stage needs to be included, in german its called a "Vollverstärker" but I can't remember the english word for this.

Speakers are selfmade transmission lines, should make about 90dB...

As stated before, I have absolutely no experience in designing tube circuits, up to now only repaired or upgraded existing ones... So I would be glad if, after some discussion, this thread might give some reliable, practically tested schematics. I think i know the basics about tubes and operation modes, but I shurely do not have the experience to turn a "standard layout" or principle into a well working amplifier. Just don't know the "dirty tricks" ...

One thing I forgot in my list above:

- I don't want to say that I dislike the "typical" tube sound, absolutely not! But in my opinion an amplifier should also have measurable qualities. A frequency response of about 25Hz-20kHz or better should be possible, and THD should be reasonably low...


Many expectations, I know, hope it isn't tooo much

Greetings
Andreas
  Reply With Quote
Old 22nd August 2005, 03:24 PM   #5
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Oeps ....both schematics I posted need a seperate preamp

[EDIT]...looks like Poinz's amp need not have a seperate preamp.

Quote:
Many expectations, I know, hope it isn't tooo much
Not at all too much....very do-able.
  Reply With Quote
Old 22nd August 2005, 05:17 PM   #6
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Quote:
Originally posted by Rundmaus
Hi Bas,

no separate Preamp, so a preamp stage needs to be included, in german its called a "Vollverstärker" but I can't remember the english word for this.

Speakers are selfmade transmission lines, should make about 90dB...

As stated before, I have absolutely no experience in designing tube circuits, up to now only repaired or upgraded existing ones... So I would be glad if, after some discussion, this thread might give some reliable, practically tested schematics. I think i know the basics about tubes and operation modes, but I shurely do not have the experience to turn a "standard layout" or principle into a well working amplifier. Just don't know the "dirty tricks" ...

One thing I forgot in my list above:

- I don't want to say that I dislike the "typical" tube sound, absolutely not! But in my opinion an amplifier should also have measurable qualities. A frequency response of about 25Hz-20kHz or better should be possible, and THD should be reasonably low...


Many expectations, I know, hope it isn't tooo much

Greetings
Andreas
I've built both circuits Bas has linked, and a few variations on each. The Wright PP1C is the better sounding of the two and is in your 10-20W spec. Mine are in storage, but iirc they were driven quite well with a standard CDP output even into less sensitive speakers then my horns. You could always build them and add a pre later, if you think it's neccessary. Use the specified Lundahl iron for them and a good PS as the cascode front end has a poorish PSRR.

Been thinking about a 6550 version (with proper chasis' this time) to drive my KEF 104/2's. I have all the parts here, but little time at the moment....
  Reply With Quote
Old 22nd August 2005, 07:14 PM   #7
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Default ecl82 ?

For a first start a ecl82 push pull amp could be a good choice. But I suppose the Allen Wright amp is soundswize better.

Question: Why the Lundahl iron ?
Suggestion: the AW amp with 807 tubes.
Attached Images
File Type: jpg stoetkit.jpg (17.3 KB, 652 views)
  Reply With Quote
Old 22nd August 2005, 07:19 PM   #8
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Default el84PP

Your countryman Huber had an interesting EL84 on the web (now disappeared (?)).
Could anybody comment on this design ?
Did anybody build or heard it ?
Attached Images
File Type: jpg el84_2c51_pp2.jpg (78.2 KB, 604 views)
  Reply With Quote
Old 22nd August 2005, 07:24 PM   #9
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Default Re: ecl82 ?

Quote:
Originally posted by Jaap
Question: Why the Lundahl iron ?
Because it's good, available, sensibly priced and what the designer recommends.
Quote:
Suggestion: the AW amp with 807 tubes.
Probably be quite nice, but won't get 10+W in class A
  Reply With Quote
Old 22nd August 2005, 07:41 PM   #10
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Default Lundahl ?

I thought that your suggestion had to do with something Allen Wright said on the tube asylum:

"In my experience, P-P amps need the standing current in the OP tubes to be VERY closely matched - or you will have a DC component in the OPT that really limits the fine detail µdynamics of the whole amp and causes it to sound closed down and lost.

Some OPTs are more sensitive to this than others: toroidals are the worst and cannot accept more than a mA before losing quality bigtime - 'normal' (non airgapped) P-P OPTs should be balanced to a mA if possible to be at their best, but Lundahls (which have a airgap even in their P-P OPTs) can be off a couple of mA without any noticiable loss."

It is not a secret that Allen has his PP-1c amp updated with a ccs under the cathodes of the outputtubes. In this way the outputstage is perfectly balanced and I think there is not a specific need for a Lundahl. You could easly use a famous vintage opt I suppose, or a cheaper one from Asia, or whatever quality-opt from own neighbourhood.
  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
Amplifier suggestions for EPA OPT please greenvalve Tubes / Valves 17 23rd April 2009 04:37 AM
Tube ID and suggestions Grathan Tubes / Valves 3 9th February 2009 12:56 AM
Tube Amp Kit Suggestions baltimoreblues Tubes / Valves 20 13th July 2008 05:53 PM
Tube Suggestions dsavitsk Tubes / Valves 13 4th August 2006 09:22 PM
Suggestions for top bal out tube pre? protos Tubes / Valves 5 26th February 2003 04:20 PM


New To Site? Need Help?

All times are GMT. The time now is 03:32 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