Looking for Very good tone control schem.

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V

vytas

Member
Joined 2003
Hello for everyone!

Please help my to find audio tone control schematics. I looking for very good (High End) solutions. I think it shuold be pasive system and it shuold regulate +-5dB for high and low bands.

I expect you understan what I mean, (I am about my English):cool:
 
mlloyd1

mlloyd1

Member
Joined 2001
I know you said "passive". However, I'd urge you to consider the active, "baxendall-like" tone control design featured in the Apt preamp from some years ago. I posted the relevant parts of the schematic some time ago (a search should find it here and a patent search should find it elsewhere - it was patented. I'd post it again but my stuff is all packed up). A key point was that it added a unity gain buffer to minimize interaction in mid band. The buffer also made the math easier - when I was younger, I liked deriving the equations for all kinds of filters and comparing the results to various simulators we used to play with. I liked the Apt preamp for it's day and I built versions of the tone control for some of my earlier preamps which are still serving friends well.

Of course, now I don't use tone controls at all, but that's another story for another day.:D

mlloyd1
 
V

vytas

Member
Joined 2003
Monday morning...

Good morning,
Thank you very much, for replay, I found some interesting things in EchWars sugestions, I shall try to implement some ideas. I understand Mlloyd1’s idea, at this moment I use two amps without tone control, and I bild one more High quality amp, in this one I wish to instal t.c. I worked about ½ year with Baxendall solution, read many articles, tried active t.c. used “tonestack” soft for calculations, used different loads…. And spend many $…
One more question: I had never tried Quad amps and preamps, are they good or just medium quality?

Thank you for replay... and greetings from Lithuania:smash:
 
A

Asen

Member
Joined 2001
QUAD control units are really VERY good. I guarantee for this even knowing that they use chip multiplexors instead of relays at the input and the rest of the circuitry. I would recommend McIntosh preamps too. C22 pre has very good controls in case you like tubes.
 
E

ergo

Member
Joined 2001
Nelson, can you please shed some more light of where to look for the mentioned Tom Holman patent.

All I found by searching is

PAT. NO. Title
1 6,405,286 Method and apparatus for determining interleaving schemes in a computer system that supports multiple interleaving schemes
2 6,272,594 Method and apparatus for determining interleaving schemes in a computer system that supports multiple interleaving schemes
3 6,108,745 Fast and compact address bit routing scheme that supports various DRAM bank sizes and multiple interleaving schemes
4 6,070,227 Main memory bank indexing scheme that optimizes consecutive page hits by linking main memory bank address organization to cache memory address organization

but none of those are of any relevance....

Ergo

PS. Tom Holman company's site is
http://www.tmhlabs.com/main/mainmenu.html
 
Steven

Steven

Member
Joined 2003
I guess you should not search for Tom Holman but for Tomlinson Holman (Advent Corporation, and later Lucasfilm), then you get patents like
5,222,059
5,189,703
5,043,970
4,569,076
4,117,412
4,032,855
Although some of these show some tone control, it seems not to be what was meant :confused: .

Steven
 
mlloyd1

mlloyd1

Member
Joined 2001
My first reply to myself (I think).

I guess I didn't actually post the schematic here, I had a link to the schematic and some text. So, here's the link:

APT Preamp Tone Control

txt file is the message that goes along with the schematic, which is the gif file.

have fun ....

I'd tell you the patent number, but all my papers are packed up in storage.

mlloyd1

And my first reply to a reply: here is the patent info:
#4,220,817 by Frank S. Kampmann (not Holman himself; and Mark Dinsmore was the designer for the power amp)


mlloyd1 said:
I know you said "passive". However, I'd urge you to consider the active, "baxendall-like" tone control design featured in the Apt preamp from some years ago. I posted the relevant parts of the schematic some time ago (a search should find it here and a patent search should find it elsewhere - it was patented. I'd post it again but my stuff is all packed up). A key point was that it added a unity gain buffer to minimize interaction in mid band. The buffer also made the math easier - when I was younger, I liked deriving the equations for all kinds of filters and comparing the results to various simulators we used to play with. I liked the Apt preamp for it's day and I built versions of the tone control for some of my earlier preamps which are still serving friends well.

Of course, now I don't use tone controls at all, but that's another story for another day.:D

mlloyd1
Click to expand...
 
dimitri

dimitri

Member
Joined 2002
Holman and Kampmann

Dear mlloyd1,
that tone control was published in Tomlinson Holman and Frank Kampmann paper "Loudness Compensation: Use and Abuse" AES 1978, July
They used extra follower Q1, thus prevent interaction between treble and bass controls completely
 
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