Tube preamp Design for Guitar - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 23rd December 2015, 07:05 PM   #1
Saus is offline Saus  Netherlands
diyAudio Member
 
Join Date: Dec 2015
Location: The Netherlands
Default Tube preamp Design for Guitar

Hello,

For the last 6 months or so i've been reading up a lot on amp building.
At some point in my life i went to the dark side (digital preamp).
And now i want a Tube Preamp, but instead of buying it, I wanna build it.
after have spending ages on sites like valvewizard.co.uk.
I think I'm ready for my first build.
i'd like your opinion on some points.

1 - I'm aiming for a high gain metal sound, is that likey with this schematic?

2 - Are there any flaws in it?

3 - Are there some extra safety features that could be added?

All other comments/info is also very welcome
Thanks ~ Paul
Attached Images
File Type: png schets 1.png (77.8 KB, 333 views)
  Reply With Quote
Old 23rd December 2015, 07:39 PM   #2
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
My favorite preamp is from the Marshall Valvestate 8100.
I had one of these amps and it got stolen, So I plan on just building the preamp section.
Orginaly I had blown the power amp and I just used the line out to my bigger rack mount amps and I still got that Incredibly Awesome sound from it!!

It is a very simple and cheap circuit to use since it is a opamp based and uses just one 12AX7.

If you still want an all tube version that I would take a look at the Marshall scematic's like the TSL series or the 2000AVT series for the nice extreme metal sound.

I played on the all tube TSL 2000 AVT when it came out in 2000 and I was just in Love with that amp but I couldn't foot the $1400 price for it.

All of those schematics can be found on line, If I had more tubes laying around I would be building one of those AVT types but I only have a few left in my parts bin and for me the 8100 Valvestae would suit me just fine.

I loved that amp, and building just the preamp would be cheaper than replacing the whole head itself.

Cheers !!

jer
  Reply With Quote
Old 23rd December 2015, 07:40 PM   #3
diyAudio Member
 
Join Date: May 2010
Location: Hawkes Bay
Looks like you have had fun

V1B needs a bias resistor.

Last edited by djgibson51; 23rd December 2015 at 07:46 PM.
  Reply With Quote
Old 23rd December 2015, 07:46 PM   #4
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
Actaully it was Called the JCM2000 TSL.
AVT was their Ad name for the All Vacuum Technology of the series.
Here is a link to all of those schematics including the Valvestate 8100.

Marshall Schematics

jer

P.S. Another great amp that I have played and almost bought is the awsome sounding Peavey 5150 and those schematics can be found here,

https://www.google.com/search?num=10...72.uKdFfo053cQ

Last edited by geraldfryjr; 23rd December 2015 at 07:53 PM.
  Reply With Quote
Old 23rd December 2015, 08:00 PM   #5
Saus is offline Saus  Netherlands
diyAudio Member
 
Join Date: Dec 2015
Location: The Netherlands
Thanks for the links,
i've already seen much examples of other amps.
my design is aimed at good sound/low cost i.e. not too many switches and functions, at least not until i need them.
  Reply With Quote
Old 23rd December 2015, 08:02 PM   #6
diyAudio Member
 
leadbelly's Avatar
 
Join Date: Dec 2002
Location: Calgary, Alberta
I would put another cathode follower at the output to buffer the tone stack.

I won't recommend that you just build a design since you have obviously learned a lot about design and are excited to build your own. Suggest you look at a commercial preamp like the Soldano X88R for ideas on final touches. Also Merlin's book is excellent, and you seem to have read all of his website so you should enjoy it.
__________________
The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts. Bertrand Russell
  Reply With Quote
Old 23rd December 2015, 08:53 PM   #7
Saus is offline Saus  Netherlands
diyAudio Member
 
Join Date: Dec 2015
Location: The Netherlands
@djgibson , doesn't it already have a bias resistor, or have I missed something ?

Verstuurd vanaf mijn ST21i met Tapatalk
  Reply With Quote
Old 23rd December 2015, 10:25 PM   #8
diyAudio Member
 
Join Date: Sep 2013
Location: Minneapolis, MN
Quote:
Originally Posted by djgibson51 View Post
Looks like you have had fun

V1B needs a bias resistor.
Do you mean a grid leak resistor? 2.7k sets bias.
  Reply With Quote
Old 23rd December 2015, 11:28 PM   #9
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
V1B has a path to ground through the drive and gain pots, but relying on two pots for a ground can lead to a scratchy static sound as the knob is turned. I would add a resistor from the wiper of the drive pot to ground, maybe 1 to 2 meg. Yes, it will cost some gain, so experiment with higher values if needed.

Quote:
I'm aiming for a high gain metal sound, is that likey with this schematic?
Probably, but the only way to tell is to build it and find out. Tons of gain is only part of the picture, how each stage overloads, and when, determines how "touch sensitive" the overall combination will be. This is why you will see gain being purposefully being thrown away between stages in some popular "high gain" amps.

Build it, get it working, then DOCUMENT it so you can get back there, and experiment. Try ONE thing at a time. Simple things like a large grid stopper resistor can affect the way a tube overloads, and dramatically change the "tone."

it takes a bit of experimenting to find the sound that you like, then a year or so later, you grow tired of it, so.......20 years later I'm still tinkering. I think I have heard all that a 12AX7 can offer, so I have been trying other tubes. There are a lot of tones just waiting to be unlocked inside some common pentodes.........
__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
  Reply With Quote
Old 24th December 2015, 12:51 AM   #10
Saus is offline Saus  Netherlands
diyAudio Member
 
Join Date: Dec 2015
Location: The Netherlands
Quote:
Originally Posted by tubelab.com View Post
V1B has a path to ground through the drive and gain pots, but relying on two pots for a ground can lead to a scratchy static sound as the knob is turned. I would add a resistor from the wiper of the drive pot to ground,
Thanks , i will implement this
And i'll probably start building soon !
  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
Guitar Tube Preamp fermaciel1771 Instruments and Amps 6 15th July 2013 09:07 PM
small preamp design for a bass guitar Gene_Johnson Instruments and Amps 42 25th November 2009 05:12 PM
Low Voltage Tube Solidstate Guitar preamp design ... Minion Instruments and Amps 12 23rd April 2009 06:06 PM
Looking for tube guitar preamp high-fi Instruments and Amps 10 24th May 2006 03:27 PM
Guitar Tube Preamp Kaiowas Instruments and Amps 5 24th April 2004 11:21 PM


New To Site? Need Help?

All times are GMT. The time now is 12:29 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright ©1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki