5687 Preamp as I plan to build it. - 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 15th July 2004, 10:52 PM   #1
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Default 5687 Preamp as I plan to build it.

Hi All,

Here is the 5687 preamp as I plan to build it. Simple and to the point. I'm going to brave the hazards of AC filament voltage on this project. Hopefully my layout and grounding scheme will be up to the task. I decided on the 5y3 because of the minimal current demand. Any suggestions are welcome.
Attached Images
File Type: gif 5687 preamp ( small ).gif (6.4 KB, 831 views)
__________________
Gavin
  Reply With Quote
Old 15th July 2004, 10:54 PM   #2
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Here is the PSU:
Attached Images
File Type: gif 5687 preamp psu ( small ).gif (11.0 KB, 649 views)
__________________
Gavin
  Reply With Quote
Old 18th July 2004, 11:20 AM   #3
diyAudio Member
 
Join Date: Nov 2002
Gavin

When I built my 5687 I used a VR regulated supply and it sounded better with it than without. I also used 30H chokes in the power supply and DC on the filaments.

It is a nice sounding line stage but somewhat pale when up against a 12B4 line stage.

Joe
  Reply With Quote
Old 19th July 2004, 02:47 AM   #4
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Hey Fingers. Did you use a tube regulated supply or a SS regulated supply? Can you post a diagram? I'm actually considering using a shunt regulated supply with OD3s. Aren't you proud Frank and SY?
__________________
Gavin
  Reply With Quote
Old 19th July 2004, 02:58 AM   #5
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Gee, seems like a waste of a 5Y3 to me. :P (20H chokes too, but I digress.) A 6X5 would work, you might be able to find a stylish model, Idunno...

Properly handled, you'll find AC heaters work very nice indeed.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 19th July 2004, 03:31 AM   #6
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Quote:
Originally posted by burnedfingers
Gavin

When I built my 5687 I used a VR regulated supply and it sounded better with it than without. I also used 30H chokes in the power supply and DC on the filaments.

It is a nice sounding line stage but somewhat pale when up against a 12B4 line stage.

Joe
I suppose I will have to avoid listening to 12B4A linestages.

__________________
Gavin
  Reply With Quote
Old 19th July 2004, 03:42 AM   #7
diyAudio Member
 
Join Date: Nov 2002
Quote: Properly handled, you'll find AC heaters work very nice indeed.


Gee, I suppose a VR regulated supply and rectifier tube would be a waste also.
  Reply With Quote
Old 19th July 2004, 04:37 AM   #8
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Well, as a coincidence the two amps I use (Frankenhouse and Hept'AU7) both have rectifiers, but they just happen to have more power and sound most similar than anything else I have. I'm a lazy builder

You can reg if you want but it won't affect anything as far as I'm concerned.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 19th July 2004, 04:38 AM   #9
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
I see nothing wrong with the 12B4. I haven't done anything besides a really abusive circuit but it looks great. Maybe I'll build a PPP or PSE amp some day with 'em...

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 19th July 2004, 05:00 AM   #10
DougL is offline DougL  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Wheaton IL.
Blog Entries: 30
I was curious about your design, so I broke out the sim tools.

Chose 29 Ma as the bias current. Got that from a tube cad simulation of the circuit. The circuit sim looked good.

I ran a simulation on Duncan amp tools.
It looked to me that the supply had some ringing.
You may want to re-visit your design.

This may or may not be an issue in the real circuit.
Just thought you would want to know.

Cheers;

Doug
  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
5687 preamp transformer losacco Tubes / Valves 2 1st May 2009 12:21 AM
DIY 5687 Preamp BillyF Tubes / Valves 17 14th February 2007 07:13 PM
Distorting 5687 preamp circuit dsavitsk Tubes / Valves 13 14th June 2006 02:31 AM
a simple preamp with 5687 tubes karma Tubes / Valves 3 23rd April 2003 08:44 PM


New To Site? Need Help?

All times are GMT. The time now is 04:37 PM.


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