Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

Vaccum tube Equalizer schematic?
Vaccum tube Equalizer schematic?
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 11th January 2018, 03:05 AM   #1
rhythmsandy is offline rhythmsandy
diyAudio Member
 
Join Date: Aug 2012
Vaccum tube Equalizer schematic?
Default Vaccum tube Equalizer schematic?

I want to build a vaccum tube equalizer can any one recommend one?
  Reply With Quote
Old 11th January 2018, 03:45 AM   #2
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Jack's Photos: The Blonder-Tongue Audio Baton
blonder tongue audio baton eq - Google Search

Here's a classic one. Jack's Photos: The Blonder-Tongue Audio Baton

Click the image to open in full size.
  Reply With Quote
Old 11th January 2018, 03:55 AM   #3
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
GoatGuy's Avatar
 
Join Date: Dec 2012
Location: SF Bay Area
Why?

OLD SCHOOL equalizers are a pain in the âhrse to do right. You need band-pass AND band-notch. Your band-to-band roll-off needs to be really accurate so when all the bands are remixed, the output "at all-zero" is indeed almost exactly unmodified from the original coming in the front.

OLD SCHOOL would have 4 pole or 6 pole band-pass/cut filtering. Each with its own accurately matched either linear or coaxially mounted pair of potentiometers. Ideally, "old school" would have you pouring thru dozens of then-popular commercial designs, as the "commercial boys" more or less worked out all the poles-phases-and-values magic.

There is a reason why OLD SCHOOL was at first - and for a long time - entirely semiconductor. And rapidly migrated to low-noise op-amps for more compactness, higher reliability and better passband-to-passband matching. And to move to 6 pole or 8 pole designs. With one or more of them being Bessel filters instead of Butterworth. Or even Chebychev-Bessel combinations.

Most recently, almost all this now fits in "a chip". But still … there is the OLD SCHOOL:

http://www.elektropage.com/images/ic...izer_ZF33B.gif

That's kind of MIDDLE school. Using op-amps to reintegration all the bandpass filters back to the bus.

So, at the very least, you'd need about 20 competent triode-stages per stereo channel. Could use 12 AX7's, or perhaps higher current devices. But in the end you'd need a lot of tubes.

With "a lot of tubes" comes "a lot of heartache". Matching problems, tubes mysteriously going stupid on you, capacitors shorting, and pretty stiff power supplies.
_______

Are you SURE you want to do this?
If so, start searching for schematics.

GoatGuy
__________________
Burnished unicorn horn circuit design only goes so far. When the magic disappoints, its best to rely on solid maths. Just Saying
  Reply With Quote
Old 11th January 2018, 06:04 AM   #4
kodabmx is online now kodabmx  Canada
Spreading triode love.
diyAudio Member
 
Join Date: Oct 2011
Location: Toronto
Vaccum tube Equalizer schematic?
Figure 16 on this page: Practical Tone Controls.
  Reply With Quote
Old 11th January 2018, 12:08 PM   #5
LAZAROIU is offline LAZAROIU  Romania
diyAudio Member
 
Join Date: Nov 2008
Location: 135200
Or a good project here:

Röhren-Equalizer
  Reply With Quote
Old 11th January 2018, 01:41 PM   #6
stellavox is offline stellavox  United States
diyAudio Member
 
Join Date: Jan 2007
Location: Oneonta, NY; USA
Default Simple and Recommended

Built two of these. Work and "sound" very nice.

Recommend the same center frequencies as in the Cello Audio Palette: (around) 20, 120, 400/800; 1K/2K, 5K, 20K. Added switches to vary two of the mid-frequencies. This design will give you around 3-4db of Boost/Cut which I've found is all you need at the mids. More in the lows is nice - especially for early LP's.

Now use my own version of the Palette Preamplifier - with an umbilical so I can control "things" from my listening position.

Charles
Attached Images
File Type: jpg Tube Equalizer.jpg (553.4 KB, 717 views)
File Type: jpg EQoutside.jpg (481.1 KB, 707 views)

Last edited by stellavox; 11th January 2018 at 02:02 PM.
  Reply With Quote
Old 11th January 2018, 03:00 PM   #7
Lingwendil is offline Lingwendil  United States
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
I've had a perverse desire to build something similar to this for years, and can already see some ways to improve on this... Higher supply voltage, current sources in the LTP and cathode follower load resistors (which will allow for much, much lower negative rail voltage) and maybe a DC servo on the output with a mute/dethumper circuit... Could borrow some aspects from Sy's Heretical preamp to make this super fancy....

Hmmmm.

Also, now that I think about it more it would be fairly simply to use the 6N2P in lieu of the 12AX7 to save some cash, and that would let you buy a few extra sets of tubes to be able to pick the ones that have better parameters for equal effect in each channel... It would be also pretty good to replace the 12AT7 with a 6DJ8 for lower output impedance, and higher available drive current, which would make it overall a pretty useful preamp for the guy who wants it all. Distortion of .0001 at 1V is pretty good already, but with a few tweaks you can have a pretty affordable EQ that is pretty decent performance.
__________________
6SN7 Push-pull Flea Amplifier PCB files are now available!
  Reply With Quote
Old 11th January 2018, 05:08 PM   #8
kodabmx is online now kodabmx  Canada
Spreading triode love.
diyAudio Member
 
Join Date: Oct 2011
Location: Toronto
Vaccum tube Equalizer schematic?
Plus that the 6N2P is a much better tube.
12AX7: "Just curious, no I would never use this tube" Tube Tester Files - 12AX7WB Sovtek
6N2P: Tube Tester Files - 6N2P - 6H2P
  Reply With Quote
Old 22nd September 2018, 09:14 PM   #9
TurvenuijaFIN is offline TurvenuijaFIN  Finland
diyAudio Member
 
Join Date: Jul 2013
Is anybody build "The Blonder-Tongue Audio Baton" equalizer for hifi use?

What it sounds?
i'd like built full tube eq for hifi use. But i thinking sound quality.
  Reply With Quote
Old 14th February 2019, 09:55 AM   #10
kissabout2002 is offline kissabout2002  Italy
diyAudio Member
 
Join Date: Sep 2018
Location: Philippines
Quote:
Originally Posted by stellavox View Post
Built two of these. Work and "sound" very nice.

Recommend the same center frequencies as in the Cello Audio Palette: (around) 20, 120, 400/800; 1K/2K, 5K, 20K. Added switches to vary two of the mid-frequencies. This design will give you around 3-4db of Boost/Cut which I've found is all you need at the mids. More in the lows is nice - especially for early LP's.

Now use my own version of the Palette Preamplifier - with an umbilical so I can control "things" from my listening position.

Charles
Hi Stellavox,

so did you build the 10 band eq by the magazine picture? I am asking because I want to built one too, I was just surprise using a simulator that there a big attenuation on the output, but of course simulator can make mistakes that's why I need some confirmation from somebody already build it....best regards
  Reply With Quote

Reply


Vaccum tube Equalizer schematic?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Are we committing suicide?! (Asbestos in vaccum tube base) ARIYAHOOR Tubes / Valves 41 13th June 2012 06:07 PM
Minature Vaccum Tube Question Mark A. Gulbrandsen Tubes / Valves 12 1st June 2005 05:01 AM
Lm4780 with vaccum tube almu100 Chip Amps 0 27th February 2005 02:48 PM
MXR Equalizer Model 170 schematic needed rh1530 Instruments and Amps 0 24th January 2004 02:54 AM


New To Site? Need Help?

All times are GMT. The time now is 07:46 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki