Sure, I'll pull together the files and post them here is a zip file. However be warned, this PCB has not been tested!
Or if you can wait for a few weeks I'll send the board a fab house and build it to be sure that it works as expected. Your choice.
Yes please
I don't intend to spend my time fiddling with the controls but I would like to be able to undo some of the damage done by mixing engineers as well as tune the system more to my room and listening preferences.
We have a chance with this design of a world-class DIY line amplifier / control system, the sort of thing that justifies spending serious money on a decent cabinet.
I am certainly in the queue for the finished board...and I look forward to the discussions that will certainly follow once a few of us have got it up and running.
See you in the forums!
George
I am pleased to see the renewed interest in tone controls, even if it is coming from the more "mature" end of the audio spectrum.
I don't intend to spend my time fiddling with the controls but I would like to be able to undo some of the damage done by mixing engineers as well as tune the system more to my room and listening preferences.
We have a chance with this design of a world-class DIY line amplifier / control system, the sort of thing that justifies spending serious money on a decent cabinet.
I am certainly in the queue for the finished board...and I look forward to the discussions that will certainly follow once a few of us have got it up and running.
See you in the forums!
George
Lol that must have been one of the worse ideas letting some of those now tone deaf 60s/70s musicians anywhere near remastering controls. Will be watching this thread also....
Trolling or just uninformed?
I suggest that the persons who are doing the re-mastering which are of concern are not, in fact, of that age group. Why don't you pul out several of the CDs which you believe are bad (or have gotten the bad rep), write down the names of the remastering engineers and producers, and then do a web search? You might be surprised. Furthermore, if you knew ANYTHING about the misc biz, it is often the business types who direct and approve the remastering of the "classic" stuff from the 50s, 60s and 70s.
Further, most of the bad rep of recent remasterings is related to additional compression (often multi band). This is not the same as EQ ("tone control" to you).
Finally, if you read my post, you would see that I am talking about boosts of 1-3 db which shelve.
I suggest that the persons who are doing the re-mastering which are of concern are not, in fact, of that age group. Why don't you pul out several of the CDs which you believe are bad (or have gotten the bad rep), write down the names of the remastering engineers and producers, and then do a web search? You might be surprised. Furthermore, if you knew ANYTHING about the misc biz, it is often the business types who direct and approve the remastering of the "classic" stuff from the 50s, 60s and 70s.
Further, most of the bad rep of recent remasterings is related to additional compression (often multi band). This is not the same as EQ ("tone control" to you).
Finally, if you read my post, you would see that I am talking about boosts of 1-3 db which shelve.
Oh Dear
Well, I don't really want to start a tone-control war.. personal preferences and all that make it irrelevant.
However, a long time ago there was interest in Fletcher-Munson curves being applied to playback to compensate for the ear's behaviour at varying volumes. If that was sound physics then, then I assume that it is now. No longer being a purist, I am happy to adjust any controls, positioning, etc to achieve a sound which I prefer. Tone controls happen to be an option which I feel is missing. After all, I think we have largely abandoned trying to achieve the "closest approach to the engineers headphones" as a quality criteria in favour of personal choice.
Well, I don't really want to start a tone-control war.. personal preferences and all that make it irrelevant.
However, a long time ago there was interest in Fletcher-Munson curves being applied to playback to compensate for the ear's behaviour at varying volumes. If that was sound physics then, then I assume that it is now. No longer being a purist, I am happy to adjust any controls, positioning, etc to achieve a sound which I prefer. Tone controls happen to be an option which I feel is missing. After all, I think we have largely abandoned trying to achieve the "closest approach to the engineers headphones" as a quality criteria in favour of personal choice.
Just a quick update ...
Thanks to prodding from George Brooke, Jan Didden and others, I have recently sent the previously described PCB off for fabrication. The project as presented will be true to that published by Doug Self in Linear Audio #5. The PCB will be in 2 pieces to allow for flexibility in cases sizing and number of IO.
I'll start a new thread once I've qualified the PCB as worthy and post notice here. I will make available an inexpensive kit of PCBs and hard to find parts (pots and connectors) for those interested in building their own.
Thanks to prodding from George Brooke, Jan Didden and others, I have recently sent the previously described PCB off for fabrication. The project as presented will be true to that published by Doug Self in Linear Audio #5. The PCB will be in 2 pieces to allow for flexibility in cases sizing and number of IO.
I'll start a new thread once I've qualified the PCB as worthy and post notice here. I will make available an inexpensive kit of PCBs and hard to find parts (pots and connectors) for those interested in building their own.
Hello Michael Bean,
I share the same views - I found the majority of tone controls available on gear to be unuseable. I read the Accelerated Slope Tone Control paper several years ago and have viewed some shelving circuits in the meanwhile.
I understand that your circuit imparts far less phase distortion. Have you been able to take some bandwidth, noise, distortion and impulse response meaurements since your last revision? If the circuit has inherently good perormance with low-noise Analog Devices opamps, the LT3042 LDOs ($3.22 each) might be a good pairing. I appreciate your thoughts!
I share the same views - I found the majority of tone controls available on gear to be unuseable. I read the Accelerated Slope Tone Control paper several years ago and have viewed some shelving circuits in the meanwhile.
I understand that your circuit imparts far less phase distortion. Have you been able to take some bandwidth, noise, distortion and impulse response meaurements since your last revision? If the circuit has inherently good perormance with low-noise Analog Devices opamps, the LT3042 LDOs ($3.22 each) might be a good pairing. I appreciate your thoughts!
Hi kouiky,
Unfortunately life issues have gotten in the way for the last few years. Deaths in the family, job layoffs, and personal health issues (nothing fatal thankfully) have slowed the pursuit hobbies and fun stuff. I do intend to get back in the saddle soon though, I'm finishing up the drawings for my latest speaker project, and intend to fire up the table saw as soon as I get them done.
As far as the tone control, I never got any further than the completed prototype before all hell broke loose, but as time permits I'll get some boards made and build one for real. A friend of mine has been using the prototype I built for several years now and is happy with it. I did manage to get measurements on the first version and there weren't any issues with it, so I presume there wouldn't be any problems with the last version either. I plan to post the PCB's and final results when I can get it done, but don't hold your breath waiting for it, it may be a while. In the mean time feel free to tackle one for yourself, and let me know how it went if you do.
Mike
Unfortunately life issues have gotten in the way for the last few years. Deaths in the family, job layoffs, and personal health issues (nothing fatal thankfully) have slowed the pursuit hobbies and fun stuff. I do intend to get back in the saddle soon though, I'm finishing up the drawings for my latest speaker project, and intend to fire up the table saw as soon as I get them done.
As far as the tone control, I never got any further than the completed prototype before all hell broke loose, but as time permits I'll get some boards made and build one for real. A friend of mine has been using the prototype I built for several years now and is happy with it. I did manage to get measurements on the first version and there weren't any issues with it, so I presume there wouldn't be any problems with the last version either. I plan to post the PCB's and final results when I can get it done, but don't hold your breath waiting for it, it may be a while. In the mean time feel free to tackle one for yourself, and let me know how it went if you do.
Mike
Per my promise ...
I have started a discussion and build thread for the preamplifier designed by Doug Self that appeared in the #5 issue of Linear Audio magazine. Here is a quick preview ...
The thread is here: http://www.diyaudio.com/forums/analog-line-level/280458-doug-self-preamp-linear-audio-5-a.html#post4468265
I have started a discussion and build thread for the preamplifier designed by Doug Self that appeared in the #5 issue of Linear Audio magazine. Here is a quick preview ...
The thread is here: http://www.diyaudio.com/forums/analog-line-level/280458-doug-self-preamp-linear-audio-5-a.html#post4468265
check out this thread:
https://www.diyaudio.com/community/...d-on-james-baxandalls-topology-wanted.195993/
https://www.diyaudio.com/community/...d-on-james-baxandalls-topology-wanted.195993/
Would like to give thanks Michael for this thread and schematics.
I have built the version without BSC (and it's good that I didn't attempt to implement it, due to space limitations.) Used OPA1656 on adapter board, P2P. I must admit it looks not too nice inside, like a nest. Mainly due to funds being limitation I used what I had, therefore the result. Also added bunch of latching relays, to have inverted triode which basically works as attenuator at input due to it's gain being approx. 1/mu. That's for some sources that have really hot input. Then there's also tube gain stage on output, which can be turned on/off for when there's opposite situation with source (low) or some low gain amp is used.
Still need to label things and maybe add small neon bulb for on/off indicator.
I have built the version without BSC (and it's good that I didn't attempt to implement it, due to space limitations.) Used OPA1656 on adapter board, P2P. I must admit it looks not too nice inside, like a nest. Mainly due to funds being limitation I used what I had, therefore the result. Also added bunch of latching relays, to have inverted triode which basically works as attenuator at input due to it's gain being approx. 1/mu. That's for some sources that have really hot input. Then there's also tube gain stage on output, which can be turned on/off for when there's opposite situation with source (low) or some low gain amp is used.
Still need to label things and maybe add small neon bulb for on/off indicator.
