Getting started with tube preamps - 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 3rd January 2004, 05:43 PM   #1
diyAudio Member
 
Join Date: Jan 2004
Location: Netherlands
Default Getting started with tube preamps

Hello folks,

I want to make a preamp using tubes. I have no idea where to start though. Should I buy one of those really old radios and take the tubes/transformer from those, or should I buy all components one-by-one?

I have plenty of electronics experience, but the field of tubes is very new to me. I was first going to make a complete amp with tubes but I think I'm going to keep it solid state for now - let's first get a preamp running. ;)

Any help would be greatly appreciated.

Regards,
-- Charl
  Reply With Quote
Old 3rd January 2004, 06:40 PM   #2
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
line stage or with a phono-pre?

A line amp can be pretty much a single tube + a power supply.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 3rd January 2004, 06:47 PM   #3
diyAudio Member
 
Join Date: Jan 2004
Location: Netherlands
Hey,

Just a line stage - I'm using the output from my computer's soundcard. I do want the absolute best sound from this thing though. Money isn't an issue. I'd be happy to stick 10 tubes per channel in if it would get me better sound. ;)

-- Charl
  Reply With Quote
Old 3rd January 2004, 08:06 PM   #4
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
From recent threads on the same subject, a single 12B4 per channel is a good way to go... most of the work is in the power supply, which for a really good pre should be regulated -- i'd use a choke loaded supply running into a Vacuum State SuperReg (a shunt reg kit).

IIRC Gary Pimm (check for some of Brett's posts) has a good site on building regulators.

There is also a thread "Frank's Ultimate Pre" that has another take on the subject.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 3rd January 2004, 08:53 PM   #5
diyAudio Member
 
Join Date: Jan 2004
Location: Netherlands
Hey,

Thanks for referring me to that post. It does have a lot of schematics though, so again I wouldn't know which one to (try) to start building. ;)

Also, it would be nice if my preamp would have some gain, maybe 2.

Perhaps I should just look for some tubes, buy them, then build something based on that instead of trying to build something based on a certain schematic?

-- Charl
  Reply With Quote
Old 3rd January 2004, 09:29 PM   #6
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Default Cost no object?

What does your line stage need to do? More to the point, do you really need it? If it's simply feeding a nearby stereo power amplifier, why not simply add input slection and volume control to the power amplifier? The very best line stage is always inferior to a piece of wire. (Farewell, Peter Walker.) On the other hand, if you need to drive remote power amplifiers, then a carefully designed cathode follower is required. I can't believe that you need gain? Think hard. All line stages cost money and degrade the sound, so you need a very good reason for using one...
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 3rd January 2004, 09:35 PM   #7
diyAudio Member
 
Join Date: May 2003
Location: Morton, Illinois
Default Line stage

Yes, if the amp already has enough gain, then the preamp is actually built into the amp so to speak. Why duplicate. Always keep the number of stages low and accurate if possible.

I took a different approach and outboarded the first stage. This was to decouple the amp from the preamp. However, it would be very difficult to rewire your existing amp.

Happy new year.
  Reply With Quote
Old 3rd January 2004, 09:48 PM   #8
diyAudio Member
 
Join Date: Jan 2004
Location: Netherlands
Hello fellows,

Yes, of course I could just tweak my (solid state) amp a bit. But I want to make a versatile pre-amp with equalizer and volume control - both computer (software) operated. I thought it would be a nice learning experience to do it with tubes. And let's face it, wouldn't they look gorgeous behind some plexiglass? ;)

This amp won't last that much longer too, I will be upgrading it in a couple of years. This way I don't have to do any modification to the preamp, I can just leave it where it is and replace the amp itself.

Still don't know what to do - find a good schematic and search for the tubes that it uses, or find good tubes and search for a schematic or design my own schematic for them?

-- Charl
  Reply With Quote
Old 3rd January 2004, 10:54 PM   #9
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Fact 1: Valves can look gorgeous.
Fact 2: Valves can sound gorgeous.
Fact 3: Valves are expensive. (Apologies Sch3mat1c, but it's true unless you spent lots of money acquiring the knowledge of how to design with cheap valves.)

Fact 2 is not absolute.

Careful software control could allow a beautifully ergonomic pre-amplifier. Have you listened to a valve amplifier and been seduced? If you haven't, why bother? If you have, get into design and build a purpose-built stunner!
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 3rd January 2004, 11:06 PM   #10
diyAudio Member
 
Join Date: Jan 2004
Location: Netherlands
Hello,

Okay - enough about how good tubes are. ;)

Any schematics? I thought I could just use some schematics with very common tubes (EL34 appears popular). I'll always be able to find them somewhere.

-- Charl
  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
Is there much point in tube preamps? (This isn't a troll) bigwill Tubes / Valves 73 10th February 2008 11:04 AM
I started my new Tube DAC Algar_emi Digital Source 139 21st November 2006 08:14 PM
Power supplies in mic tube preamps JamMan Tubes / Valves 5 2nd November 2004 02:48 PM
commercial tube preamps bonsai171 Tubes / Valves 12 17th March 2004 06:56 PM
tube preamps and gain bonsai171 Tubes / Valves 3 14th March 2004 12:13 AM


New To Site? Need Help?

All times are GMT. The time now is 05:07 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