Hi, as you can see, I am new here.
I am starting this thread with a specific type of NR in mind--- dbx type II.
Currently, in my home studio, my multitrack deck(Tascam MF-P01), and my mastering deck(Teac 4010 reel-to-reel) are lacking any sort of noise reduction. I have been looking into incorporating a dbx console(or consoles) into my system for noise reduction.
Finding information on such consoles has proved more difficult than I once thought it would be. dbx's official site (http://www.dbxpro.com/) has only limited archives of information on it's discontinued products (dbx 122, 941, etc.).
For my studio, I would need a unit with unbalanced 1/4 inch outputs for going to my multitrack deck[**actually this unit could be a single channel unit- as I can only record one track at a time**], and a unit with RCA ins/outs for mixdown/mastering.
If anyone here has any sort of information on dbx units that would work for these applications, it will be most welcome!
I would especially like it if someone could get me a complete schematic... that way I could build the units myself!
Thanks,
Sir Trefor
I am starting this thread with a specific type of NR in mind--- dbx type II.
Currently, in my home studio, my multitrack deck(Tascam MF-P01), and my mastering deck(Teac 4010 reel-to-reel) are lacking any sort of noise reduction. I have been looking into incorporating a dbx console(or consoles) into my system for noise reduction.
Finding information on such consoles has proved more difficult than I once thought it would be. dbx's official site (http://www.dbxpro.com/) has only limited archives of information on it's discontinued products (dbx 122, 941, etc.).
For my studio, I would need a unit with unbalanced 1/4 inch outputs for going to my multitrack deck[**actually this unit could be a single channel unit- as I can only record one track at a time**], and a unit with RCA ins/outs for mixdown/mastering.
If anyone here has any sort of information on dbx units that would work for these applications, it will be most welcome!
I would especially like it if someone could get me a complete schematic... that way I could build the units myself!
Thanks,
Sir Trefor
Hi Trefor,
maybe you can take a look here:
DBX Schematics
Just a small remark: these schematics are probably copyrighted, and are anyway DBX' s intellectual property, so I do not really know whether you can reproduce their equipment...
Cheers,
Bruno
maybe you can take a look here:
DBX Schematics
Just a small remark: these schematics are probably copyrighted, and are anyway DBX' s intellectual property, so I do not really know whether you can reproduce their equipment...
Cheers,
Bruno
My thoughts on excessive signal processing
It is really difficult to get the best record and reproduce quality available with stock reel-to-reel analog electronics. Performance can be increased drastically with the use of custom-built electronics. From a purist point of view and before using any type of noise reduction I would investigate methods of improving the recorders themselves. This would include adding external reproduce amplifiers. I have done this for one recording studio in New York in the past and a great improvement in background noise and sound quality was noticed by them when re-mastering some old analog tapes and converting them to a digital format.
Most recording studios use items, such as noise gates, limiters, linear compressors or those with a frequency selective compression and expansion techniques such as DBX during live recording sessions. But if you are working with different program material then compression and expansion techniques may not be required depending on the quality of equipment being used. The general rule is to eliminate as much as possible of this kind of equipment.
Don’t add DBX or other boxes to hide potential system problems. Some of the finest recordings ever made were made with reel-to-reel analog recorders without any kind of noise reduction. Track width of course has a great effect, so if you are trying to put a lot of tracks on a narrow tape it will compound noise problems. If you are laying down one track at a time and then using that track to add additional material to, and then recording the sum again and so forth then there is likely little that can be done to keep signal quality high. For mixing such as that it is likely best to do it in the digital domain.
I have worked with and built analog recorders from time to time since before 1965, and presently own a Studer B67 and A80 along with an Ampex 440C transport that I use for testing and doing custom design work with. The heads in the old Studer/Revox machines are just fantastic and extremely hard to beat for performance.
Anyhow these are my thoughts at the present time.
Johannes
It is really difficult to get the best record and reproduce quality available with stock reel-to-reel analog electronics. Performance can be increased drastically with the use of custom-built electronics. From a purist point of view and before using any type of noise reduction I would investigate methods of improving the recorders themselves. This would include adding external reproduce amplifiers. I have done this for one recording studio in New York in the past and a great improvement in background noise and sound quality was noticed by them when re-mastering some old analog tapes and converting them to a digital format.
Most recording studios use items, such as noise gates, limiters, linear compressors or those with a frequency selective compression and expansion techniques such as DBX during live recording sessions. But if you are working with different program material then compression and expansion techniques may not be required depending on the quality of equipment being used. The general rule is to eliminate as much as possible of this kind of equipment.
Don’t add DBX or other boxes to hide potential system problems. Some of the finest recordings ever made were made with reel-to-reel analog recorders without any kind of noise reduction. Track width of course has a great effect, so if you are trying to put a lot of tracks on a narrow tape it will compound noise problems. If you are laying down one track at a time and then using that track to add additional material to, and then recording the sum again and so forth then there is likely little that can be done to keep signal quality high. For mixing such as that it is likely best to do it in the digital domain.
I have worked with and built analog recorders from time to time since before 1965, and presently own a Studer B67 and A80 along with an Ampex 440C transport that I use for testing and doing custom design work with. The heads in the old Studer/Revox machines are just fantastic and extremely hard to beat for performance.
Anyhow these are my thoughts at the present time.
Johannes
Thanks for the insight!
You have all been very helpful!
-Trevor
Yes...I am fully aware of this fact (not trying to be condescending). But remember---- I am working with cassette recording; I have to fit as much signal as possible on a tiny, tiny track. When I read about the dbx system of straight compansion on the overall signal I was curious about it's performance---- as it is a much simpler approach to compansion than Dolby's systems of noise reduction.
Ahhh...yes...and I am a purist, I make it a point to use as little signal processing as possible---- but I am always one to take things to the absolute extreme (like making a pseudo-studio quality recording onto a four-track cassette recorder, for one).
You have all been very helpful!
-Trevor
Sir Trefor
The cassette recorders sure do pose a real challenge. I have been thinking that I have an old professional DBX unit lying around that I have not looked at for years, or plan to ever use. It has balanced inputs and outputs (XLR) connectors and can handle 4 channels. I think it would be easy to make up some cables for it that would adapt it to your equipment. It is a rack mount unit. If you would be interested in using it for your projects please send me a message. The cost would be very reasonable.
Last time I checked it all four channels were working. I do not have a book on it but I believe it to be a type II.
Johannes
The cassette recorders sure do pose a real challenge. I have been thinking that I have an old professional DBX unit lying around that I have not looked at for years, or plan to ever use. It has balanced inputs and outputs (XLR) connectors and can handle 4 channels. I think it would be easy to make up some cables for it that would adapt it to your equipment. It is a rack mount unit. If you would be interested in using it for your projects please send me a message. The cost would be very reasonable.
Last time I checked it all four channels were working. I do not have a book on it but I believe it to be a type II.
Johannes
Type 2 DBX is designed for 7.5 ips and lower while type 1 DBX is for 15 ips and up. Being a pro system type1 units have balanced inputs/outputs while the type 2 units have s/e rcas as their use was intended for the consumer market. Try and find a NX40 on ebay or suchlike - you should only need to pay $20 to $40.
DBX types
I have dug out the 4 channel DBX unit I have offered to make available, and it is model 187 which is a type 1 unit. To me it is worth more for the 16 chassis mounted XLR connectors than its circuit boards. If I end up scrapping it out would any one be interested in its circuit boards?
Johannes
I have dug out the 4 channel DBX unit I have offered to make available, and it is model 187 which is a type 1 unit. To me it is worth more for the 16 chassis mounted XLR connectors than its circuit boards. If I end up scrapping it out would any one be interested in its circuit boards?
Johannes
If it is still an open question, I could always hear my DBX 122 pumping in and out on recordings made with it. I only used it to copy LPs, but if you concentrated, you could hear it working on playback. My original intentions were to use it for live recording, but the way it worked when dubbing LPs discouraged me. I no longer have it, but I have always wondered how well it would work with a mike mixer input.
DBX Units In General
SirT,
I, too, am new to these forums, and saw your questions about the DBX unit 'pumping.' This means the unit is out of adjustment, which DBX can still do, though it will likely cost you around $100-150 to do so. IMHO, it's worth it, especially if you like your tapes and/or want to convert them to CD later...you can copy them without the encoding, because you're recording the 'outputed' version of the signal.
You might try one of the audiophile restoration outfits on the Web, like Stereo Repair In-House Stereo Company in New York, Soundsmith, or any of the outfits on boards like Audiogon, Audio Classics or other such boards. The repair places are truly good and reputable outfits, and the other boards are good, too.
Now, as to using older DBX units...if you love tape, you shouldn't be without one IMHO. Properly adjusted, they give nearly CD-quality clarity without the tape hiss, the only downside being the encode/decoding necessary. I no longer use my 122 (which I paid DBX to refurb about 5 years ago), but still use my 128 Range Expander/Decoder.
Short and sweet, if you stick with tape, stick with DBX. It hasn't failed me since 1977. (I can also make you a deal on the 122 I have, if you like...I'm trying to find some old amps and power conditioners I can use that aren't dogged out, so maybe....?)
ChuckK
Norman, OK
SirT,
I, too, am new to these forums, and saw your questions about the DBX unit 'pumping.' This means the unit is out of adjustment, which DBX can still do, though it will likely cost you around $100-150 to do so. IMHO, it's worth it, especially if you like your tapes and/or want to convert them to CD later...you can copy them without the encoding, because you're recording the 'outputed' version of the signal.
You might try one of the audiophile restoration outfits on the Web, like Stereo Repair In-House Stereo Company in New York, Soundsmith, or any of the outfits on boards like Audiogon, Audio Classics or other such boards. The repair places are truly good and reputable outfits, and the other boards are good, too.
Now, as to using older DBX units...if you love tape, you shouldn't be without one IMHO. Properly adjusted, they give nearly CD-quality clarity without the tape hiss, the only downside being the encode/decoding necessary. I no longer use my 122 (which I paid DBX to refurb about 5 years ago), but still use my 128 Range Expander/Decoder.
Short and sweet, if you stick with tape, stick with DBX. It hasn't failed me since 1977. (I can also make you a deal on the 122 I have, if you like...I'm trying to find some old amps and power conditioners I can use that aren't dogged out, so maybe....?)
ChuckK
Norman, OK
Wow, that is a very old thread, but thank you, nonetheless!
I love my dbx 122; I have had it for a while, and I cannot hear any pumping- no calibration needed, yet. I made a mixed tape for a party that I had, and was astounded at the clarity of the music- like you said, it was near-CD quality.
I do have a dbx 150X type I unit for my reel-to-reel, which may need some calibration though.
I don't have a lot to trade right now- though if I did I would let you know(unless you are looking for NOS can-type electrolytic caps...?)
Thanks again!
I love my dbx 122; I have had it for a while, and I cannot hear any pumping- no calibration needed, yet. I made a mixed tape for a party that I had, and was astounded at the clarity of the music- like you said, it was near-CD quality.
I do have a dbx 150X type I unit for my reel-to-reel, which may need some calibration though.
I don't have a lot to trade right now- though if I did I would let you know(unless you are looking for NOS can-type electrolytic caps...?)
Thanks again!
DBX 122
My bad...I only noticed after I posted to your message that the person before you had the pumping problem. I only posted because I thought I could bring another analog user to the DBX Side, as it were! (hahaha). As to trading, well, I'm not a techie, just an informed user...if I had your abilities, I'd probably have a working SPEC-1 and SPEC-4 right now, instead of waiting for the money to fix them! Cheers, ChuckK
My bad...I only noticed after I posted to your message that the person before you had the pumping problem. I only posted because I thought I could bring another analog user to the DBX Side, as it were! (hahaha). As to trading, well, I'm not a techie, just an informed user...if I had your abilities, I'd probably have a working SPEC-1 and SPEC-4 right now, instead of waiting for the money to fix them! Cheers, ChuckK
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