chrislongwood
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Does anybody have or know where to get schematics for the ol abbey roads "presence box"? A friend has the plugin on his computer and I thought to myself- how cool would it be to make one of these
Abbey roads presence box?
- Thread starter chrislongwood
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Winston OBoogie
Well-known member
Yes.chrislongwood said:
chrislongwood said:
I don't know any one who has these schematics that would be willing or able to give it up. Sorry...
...but in case anyone would like to supply it anonymously after all, simply email it from/to our group gmail account: [email protected]..
Jakob E.
Jakob E.
Silvas
Well-known member
This would make a very cool and useful project ! i usually record pretty flat but sometimes i need just a bit of sheen (when i´m away from studio´s neve console )
)Winston OBoogie
Well-known member
gyraf said:...but in case anyone would like to supply it anonymously after all, simply email it from/to our group gmail account: [email protected]..
Jakob E.
Hi Jakob.
I can say that there are ways to achieve the eq curves that are more cost effective than how the original was designed and built.
Before I explain a bit further, here's a bit of other info: All eq's at A.R. had to be fed from 200 ohms - usually the amps before them were built out to this 200 ohms with a resistor - 168r (for a V72S) or 150r (for a REDD47) or 160r (for a RS124) or whatever was necessary on a particular source to get the internal OP Z to 200r. The eq was not terminated in 200 but was usually followed by bridging impedance.
Anyway, what I did was make digital models and run simulations by entering the exact components from the eq networks in the presence box and the desk eq blueprints. Then I manipulated a passive topology which was similar to a Pultec so that the curves (points and bandwidth) matched the model. I substituted fixed resistors for pots.
As an exercise I once built an eq, right from the blueprints, just based on the desk "Pop" eq - a miserly two bander. It was an expensive piece to build for a two band eq (2 X 4 pole shorting Elma's, 3 X custom inductors etc. etc). I also built the same thing using a different topology as described above, the cost being considerably less.
The sound of the original eq's is largely the curves. They were run at fairly depressed levels so nothing untoward was/is happening with the inductors and, being passive, the other characteristics of the "tone" generally came from the amps surrounding them.
I am working on a box right now (on and off) that combines the "Pop" and "Classic" desk curves and the "Presence" box curves. This isn't a commercial box (yet? maybe someone will pick it up someday...) but it won't care what impedance you proceed it with and it will, hopefully have the tone of a REDD47 without having to use a REDD47. I've been doing some digital models of the tube circuits and am working on analogue "Plug-in" circuits using squalid-state. Won't be exact but might get close?
W.
Winston OBoogie
Well-known member
chrislongwood said:
In retrospect, I think my first response may have come over a little harsh. I didn't mean it to, especially to a first time poster.
Welcome Chris.
chrislongwood
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W- Your post didn't come off as too harsh considering my what I was asking, thanks for the welcome
Wow. You have really done your homework on the a.r. eqs, I would love to pick your brain sometime.
The box you are working on sounds very awesome- would you be interested in making it a group diy project?
Is that too much? I feel like I just asked you to share a piece of the cross with me
Wow. You have really done your homework on the a.r. eqs, I would love to pick your brain sometime.
The box you are working on sounds very awesome- would you be interested in making it a group diy project?
Is that too much? I feel like I just asked you to share a piece of the cross with me
Don't know how the plugins stand against the original units,
but I can say that they sound amazing.
but I can say that they sound amazing.
Winston OBoogie
Well-known member
chrislongwood said:
It helps to have blueprints. I'm also quite passionate about this stuff.
chrislongwood said:
There are a few factors that make me somewhat reluctant:
Firstly: I try to eek out a living of sorts from various audio related designs or builds and, while I have been, and am still willing to be, quite free with various bits of info, I generally try not to give the farm away in case a project comes down the pike that earns a bit of crust from whatever info I have acquired or a design I may have done. I could, for instance, design a PCB for the above eq and offer it for sale but, since this forum is intended as a "not for profit", I am probably not going to realize much in return. For example, in the Black Market here, I might get away with $5 on top of what a board costs me to make. By the same token, I could build one or a pair of these eqs and realize enough to pay rent for a month. I'm not all about money (I usually lean towards the broke side to be honest) but I have to be practical.
Secondly: None of this stuff is that difficult to come up with. There are several people who regularly contribute to this board that know WAY more than I do about certain aspects of audio design. No names
This is of no real relevance to what I'm trying to say, just thought I'd throw it in!! Anyway, these days I'm going to try to limit my posts to hinting at things I've found to work for me without posting schematics etc. I think it's important that people go away and try various ideas themselves, that's how you learn. That's what I do with my stuff and I always do learn something or other in the process.Thirdly (maybe finally?): I have a tendecy to disappear from here for, sometimes, long periods of time. This isn't a good thing if you're running a group project.
Especially if it's your design!! :
I would say it would be quite easy, if you have access to the A.R. presence box plug-in, to plot out the curves. Start playing around with a passive eq circuit in a simulator until you get something close to those curves. After that, build it because that's the ONLY way to know if you have something worthwhile.
W.
Ptownkid
Well-known member
I'd like to state once again that it is REALLY nice to see you here again winston.
CHeers
CHeers
chrislongwood
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W-
Just read a bunch of your old posts and I feel like I have just read a very kick ass text book.
Thanks again for your insight
Just read a bunch of your old posts and I feel like I have just read a very kick ass text book.
Thanks again for your insight
Winston OBoogie
Well-known member
chrislongwood said:
I'm afraid a lot of posts are now missing :
In hindsight, I may have been a little hasty in removing them as it makes some threads look strange. I had my reasons at the time but... old feelings and thoughts which are not important to me now Thanks for the compliments but, as I said, there are lots of people posting here who are ahead of my curve in certain aspects of knowledge. Even in the areas I tend to dabble in, I suspect, nay, I know! there are some with more extensive background in theory for a start.
Enough of that.
The curves for the Pop eq treble boost is a peak and is fairly broad. It is centred at roughly 5K (4K8 if memory serves.) The treble cut is a shelf type and the frequency shifts with the amount of cut - much like a Pultec Hi cut does.
The "Pop" bass acts at fairly high frequencies (comparatively speaking) and is shelf for both boost and cut. Frequency is also dependent on the amplitude.
W.
Winston OBoogie
Well-known member
Wait! John, you work at Sugar Hill Studios I see.
Don't you have a REDD47?
I think Keven Ryan (co author of 'Recording The Beatles) knows a coupla guys from there and also works there occasionally.
Am I barking up the wrong Sugar hill?
Don't you have a REDD47?
I think Keven Ryan (co author of 'Recording The Beatles) knows a coupla guys from there and also works there occasionally.
Am I barking up the wrong Sugar hill?
chrislongwood
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You got the right hill! John is an engineer up here also & a good friend of mine. Yes he has a redd47- but it stays locked up until he has a tracking session.
Keven and Dan are good friends too- Keven does a guest lecture in Dans audio5 class at Houston Community College
Keven and Dan are good friends too- Keven does a guest lecture in Dans audio5 class at Houston Community College
Winston OBoogie
Well-known member
chrislongwood said:
Ah ha! John Griffin yes. I built the REDD a few years ago.
I'm very good friends with Brian Kehew (Kevin's co author) and know Kevin somewhat but mostly just through emails. I saw him (Kevin) about 5 months ago when he came to do a lecture with Brian at a museum here in California. Brian and I gave him an RS124 converted Altec shortly after his trip.
I recently came down to L.A. from S.F. at Brian's request for help on a few projects and may end up staying now that I'm here...
Anyway, please say hello to John for me
John AKA W. or Winston on here
Editied coz I initially posted my reply under the wrong account without realizing a friend was still logged in!!
chrislongwood
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you built that!! you are the man! that pre sounds so amazing... amazing
Winston OBoogie
Well-known member
chrislongwood said:
Yes I did. It's a bit different than units I built more recently but is exactly the same as a unit that I sent to Abbey Road Studios so you're in good company
Glad you like it,
W.
Edit: Chris, scroll down at the bottom of the first page of this thread http://www.groupdiy.com/index.php?topic=33066.0
Since you seem interested in this old A.R. stuff, it's a picture i just posted of 4 Altecs I modified a while ago.
chrislongwood
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:drool:
