Post by: TotalSonic on February 19, 2008, 11:52:18 PM
Was browsing on your site and noticed you're listing the custom eq from the Barry Porter design in place of where there used to be the Sontec.
How do you like it? Any details you're willing to share?
Best regards,
Steve Berson
Post by: bblackwood on February 20, 2008, 07:40:32 AM
This one's not really secretive, it's almost like a Davelizer with Q controls built in - very transparent but with an ever so slight euphonic coloration. Top end is very smooth and the bottom is great for adding a 'point' on the kick.
It was laid out so you can drop either standard 8 pin dip or API/990 style op-amps into it. The variety of opamps we originally chose have gone unchanged as so far, I've not found a weakness to address.
It's really a lot of fun to use and I'm thrilled with how it came out!
Here's a couple of pics:
(http://www.euphonicmasters.com/misc/BPEQ2_1.jpg)
(http://"http://www.euphonicmasters.com/misc/BPEQ2_2.jpg)
Post by: Viitalahde on February 20, 2008, 10:43:37 AM
One of the future projects is to build another parametric EQ, and instead of re-building the current one with modifications, this design could be well worth exploring to. I first saw the design years ago, then forgot about it completely until you guys talked about it.
And the low+high band go from shelf to bell, that is always good.
Well, got to put this one on the waiting list. Need to speakers.. A passive EQ should be coming up.. NTP limiters waiting to be racked..
EDIT: Bypass on the front panel? Thought you had them in your console. Or have you ran out of inserts?
Post by: bblackwood on February 20, 2008, 10:58:51 AM
| Viitalahde wrote on Wed, 20 February 2008 09:43 |
EDIT: Bypass on the front panel? Thought you had them in your console. Or have you ran out of inserts? |
No, not out of inserts, but thought it a smart idea to include in case I ever do.
Post by: Bob Boyd on February 20, 2008, 11:28:29 AM
Post by: TotalSonic on February 20, 2008, 12:57:18 PM
| bblackwood wrote on Wed, 20 February 2008 07:40 |
I absolutely love it! This one's not really secretive, my tech can build one for anyone interested enough (PM me for his info, but don't call to kick tires). It's almost like a Davelizer with Q controls built in - very transparent but with an ever so slight euphonic colorations. Top end is very smooth and the bottom is great for adding a 'point' on the kick. It was laid out so you can drop either standard 7 pin (API) or 990 style op-amps into it. The variety of opamps we originally chose have gone unchanged as so far, I've not found a weakness to address. |
Thanks much for the info.
Do you know what opamps you went with? Did you test a lot of different things?
| Quote: |
It's really a lot of fun to use and I'm thrilled with how it came out! |
Very cool.
Does anyone know what the link to the pdf with the schematics is? I couldn't find it yet with a quick Google search.
Best regards,
Steve Berson
Post by: jdg on February 20, 2008, 01:10:30 PM
the TFPro P9 is based on it. i had the P9, i know its sound, but never a trident. does your EQ brad sound like the P9?
Post by: bblackwood on February 20, 2008, 01:32:14 PM
| jdg wrote on Wed, 20 February 2008 12:10 |
IIRC, the trident "A range" console EQs are the barry porter design. no? the TFPro P9 is based on it. i had the P9, i know its sound, but never a trident. does your EQ brad sound like the P9? |
No idea, but I doubt it sounds like much anything else - my understanding is that this was his final "ultimate EQ" design before his passing.
Certainly much of it is about implementation and my tech is stellar at understanding this, but the circuit itself isn't very colored from what I can tell.
I don't recall exactly which opamps were finally settled upon and can't find the schematic right now, but I'll see if i can scare it up when i have time.
Post by: bblackwood on February 20, 2008, 01:44:43 PM
Post by: zmix on February 20, 2008, 06:04:43 PM
| jdg wrote on Wed, 20 February 2008 13:10 |
IIRC, the trident "A range" console EQs are the barry porter design. no? the TFPro P9 is based on it. i had the P9, i know its sound, but never a trident. does your EQ brad sound like the P9? |
John,
You are correct, same Barry Porter.
This EQ is quite different than his original Trident A-Range / TFPro P9 topology.
This one is based on a state variable active filter, and as such, has no transformers, inductors or discrete gain stages....you'll love it!!
Post by: jdg on February 20, 2008, 07:41:21 PM
Post by: lowland on February 21, 2008, 10:33:53 AM
http://www.hiltongrove.com/hiltongrove_mastering.htm
Post by: JGreenslade on February 21, 2008, 03:06:09 PM
Grayhill? Elma?Is there anyway I could bribe you into releasing the Gerber files? I'm very interested in building one of these animals, and I'd like to do it with an op-amp designed by an associate. The op-amp is pin-compatible with the TL071, but has a much, much larger physical footprint... I'm guessing any Gerber would need a fair amount of re-jigging to accommodate Mr P's op-amp, but at least it'd give a basis to start on.
It's always good to see Barry Porter getting recognition - albeit posthumously.
Justin
Post by: bblackwood on February 21, 2008, 03:19:00 PM
My tech poured a TON of time laying out these boards, so I doubt he'll give the gerber files away. You could have him modify them for you perhaps? I dunno - PM me for his contact info...
Post by: JGreenslade on February 22, 2008, 08:05:03 AM
I suspect the PCB will need a lot of re-jigging to accommodate the op-amp I have in mind, and I also have a couple of ideas for other changes, so I will finalise these ideas before contacting your Tech. If you speak to him in the meantime, you could ask him how much work he reckons will be involved to convert the PCB to work with a TL071-pinned DOA.
It looks like a few people here are building these EQs - in a few months time it should be fascinating to compare builds.
Justin
Post by: Viitalahde on March 07, 2008, 02:40:39 PM
There's going to be a new parametric in my rack someday, and I'm anyway moving away from cloning to public domain and open concepts, I just like the idea.
So Brad.. How's the midrange, 600Hz-1200Hz? This is the area my current EQ kills anything I've heard, but especially in the upper mids it could be better even if the high end is brilliant.
Post by: dcollins on March 10, 2008, 10:00:44 PM
| Viitalahde wrote on Fri, 07 March 2008 11:40 |
I finally took a good look at the schematic, and understood why I completely dismissed it. I always thought this was a basic state variable circuit with the filters in series. Now I'm interested. |
There are a number of interesting aspects to that design, which is why I brought it to peoples attention in the first place!
DC
Post by: zmix on March 11, 2008, 11:50:49 AM
This way you would have a three position switch determining whether each band was going to "Cut" or Boost" or, in the center position, be "out".
This also effectively doubles the number of positions available on the attenuator.
EDIT: I see that Mike Pecchio had a similar idea here.
Post by: Viitalahde on March 11, 2008, 12:14:54 PM
| zmix wrote on Tue, 11 March 2008 15:50 |
This also effectively doubles the number of positions available on the attenuator. |
Yay, that's exactly what I do with my current EQ. No "out" though, don't know why I never implemented that. It'll be there in the next EQ, which is probably going to be this one if I like it after prototyping.
Cut/boost -switch is cool, I've been happy a couple of times that I actually have the possibility for more cut/boost than, say, 6dB. Right now I have 12dB max.. and I think I've once done 7,5dB somewhere in the high end. Argh.
Post by: T. Mueller on March 11, 2008, 02:34:50 PM
| zmix wrote on Tue, 11 March 2008 10:50 |
I think an interesting way to implement this EQ would be to run the output of each filter to a rotaty switched resistive ladder attenuator feeding a SPDT center-off switch. The center lug of the SPDT/CO switch would be connected to the attenuator following the filter's output. The outer lugs of the SPDT/CO would feed Pins 2 and 6 of U2. This way you would have a three position switch determining whether each band was going to "Cut" or Boost" or, in the center position, be "out". This also effectively doubles the number of positions available on the attenuator. EDIT: I see that Mike Pecchio had a similar idea here. |
PLEASE pardon my lack of understanding; still learning. Am I reading this right in that you're describing a way to implement attentuation with more precision/resolution to the filters? I read Mike's post; sounds like a fun project.
Post by: zmix on March 11, 2008, 03:42:32 PM
| T. Mueller wrote on Tue, 11 March 2008 14:34 | ||
PLEASE pardon my lack of understanding; still learning. Am I reading this right in that you're describing a way to implement attentuation with more precision/resolution to the filters? I read Mike's post; sounds like a fun project. |
My suggestion is probably simpler than you think it is..
Basically in this EQ, as in most active EQ circuits, the input signal is split off into two paths, one straight through to the output amp and one through an EQ filter, either a shelf or a bell (peaking) filter.
If you combine these two paths at the output amp, you will get an additive effect at the frequency of the filter.
If you invert the polarity of the filter 180˚ you will have a subtractive effect at that frequency.
In the stock circuit, each filter's "cut/boost" control is essentially a pan pot which directs the output of the filter to either the inverting input of the output amp (for cutting) or the non-inverting input (for boosting).
If you use a toggle switch (after the filter's ouput attenuator) to direct the filter's output to either the inverting or the non-inverting port in the output amp, you can use the entire travel of the "cut/boost" pot or alternately all of the positions of the rotary "cut/boost" switch towards your desired result.
To simplify it further, suppose you have an 11 position switch for the cut/boost function.
In the original schematic this will give you 5 cut positions and 5 boost positions and the middle postion is 'flat'.
In version I suggested you will have 11 positions of cut or boost and you don't waste one position to have a 'flat' setting (since the cut/boost selector toggle has an 'out' position).
Post by: T. Mueller on March 11, 2008, 04:55:03 PM
| Quote: |
In version I suggested you will have 11 positions of cut or boost and you don't waste one position to have a 'flat' setting (since the cut/boost selector toggle has an 'out' position). |
Yup. This is what I meant by "precision/resolution"--I meant amplitude. Sweet.
Post by: Greg Reierson on November 10, 2008, 06:19:31 PM
Any other brave souls with a story to share?
GR
Post by: mastertone on November 10, 2008, 07:06:27 PM
Damn i want to do this one...
Post by: hnewman on November 11, 2008, 12:44:15 PM
Post by: dcollins on November 11, 2008, 07:26:14 PM
| hnewman wrote on Tue, 11 November 2008 09:44 |
Here's mine in action. |
I'm so glad to see this design, and Barry Porters name, get some exposure.
I think it will beat the revered Sontec, and does not use any un-obtainium parts.
DC
Post by: bblackwood on November 11, 2008, 07:32:46 PM
Post by: TotalSonic on November 11, 2008, 08:10:08 PM
| hnewman wrote on Tue, 11 November 2008 12:44 |
Here's mine in action. |
It looks excellent Harris! You definitely have got some fine goodies in those racks now.
btw - what are the 4 controls in the center of it? - gain, hpf & lpf, shelves?
Best regards,
Steve Berson
Post by: TotalSonic on November 11, 2008, 08:11:30 PM
| dcollins wrote on Tue, 11 November 2008 19:26 |
I think it will beat the revered Sontec, and does not use any un-obtainium parts. DC |
Seems Harris has got the Sontec part covered as well - from the studio shots there's a modded "new" MEP250EX in the rack on the left.
Best regards,
Steve Berson
Post by: hnewman on November 12, 2008, 10:04:43 AM
Post by: Viitalahde on December 14, 2008, 04:05:25 PM
Thanks to DC for years of being stubborn, brining it to public attention!
Post by: dcollins on December 15, 2008, 03:07:42 AM
| Viitalahde wrote on Sun, 14 December 2008 13:05 |
Well, I've started to figure out what I want from mine, and I'll be ordering most of the parts needed on january. I think this is going to be a great EQ - the more I stare at the schematic, the more I see how well this thing is thought up. No magic, just engineering well done. |
I thought the same thing. The more I looked at it, the more interesting it became.
As you say, just real engineering, which is sometimes rare in audio
| Quote: |
Thanks to DC for years of being stubborn, brining it to public attention! |
Cheers.
DC
Post by: compasspnt on December 16, 2008, 02:42:59 AM
Post by: Viitalahde on December 16, 2008, 02:53:10 AM
I'm going for 23 or 24 per band, just because I happen to have a bunch of Elmas for that. Also, no boost/cut switching as previously said, it's going to be simple this time. I haven't yet decided if I want to go the Maselec-ish way of having 0,5dB steps 'till 4,5dB and then 5dB, 6dB, 8dB.
It might well be I'm going for +/-5,5dB max myself.
Hell, my new passive EQ has +/-3dB.
Post by: Alécio Costa - Brazil on December 16, 2008, 05:24:22 PM
I can't remember when I used that when mixing, imagine on a mastering task!!
Post by: compasspnt on December 16, 2008, 05:37:44 PM
| Al
Post by: TotalSonic on December 16, 2008, 07:04:15 PM Is the faceplate of the Lucas BPEQ something that you're doing as a one-off for yourself - or are you planning on manufacturing / marketing more these as part of the Lucas product line? If the latter - any idea what your asking price will be? I agree with Jaako that it is indeed much nicer to have more freq selection points - and that more overlapping of freq choices is very welcomed as well. Obviously this would be more expensive to implement though. 23 per band would probably be overdoing it for me though! - I think I'd be happy with 12. Best regards, Steve Berson Post by: Ben F on December 16, 2008, 07:32:39 PM
I'd be inclined to go that way as well. I actually think the Maselec frequency choices are perfect- better than a Sontec. They overlap very nicely for cutting in the low/mids. Post by: T. Mueller on December 17, 2008, 09:05:30 AM Post by: bblackwood on December 17, 2008, 09:16:42 AM Also, if you have any specific questions about the EQ, please post them here rather than via PM - that way everyone can see and it saves me time answering the same questions over and over... Post by: Greg Reierson on December 17, 2008, 09:35:20 AM
I also put a bypass on each band but skipped the master bypass since I have one in the router. I'm quite happy with 12 frequency centers per band. GR Post by: 24-96 Mastering on January 21, 2009, 03:44:45 PM To anyone who was used both designs, how are they related, sound-wise? How do they differ? Post by: dcollins on January 21, 2009, 04:18:44 PM
They have nothing in common as far as the topology is concerned. DC Post by: 24-96 Mastering on January 21, 2009, 08:38:05 PM
Thanks. Is there any commercially available unit using the BP topology or is currently the only way to hear it to comission a DIY build? Post by: T. Mueller on January 22, 2009, 08:02:13 AM Post by: zmix on January 22, 2009, 09:04:49 AM
Very different. The "Barry Porter EQ" is based on a common "State Variable Filter", which is a textbook 'multimode' filter designed around 4 opamp stages per filter capable of simultanous HP, LP, BP and notch outputs. If the notch output is not required, it can be built with 3 opamp stages per filter. The filter is a second order design (12dB/oct). The TF Pro P9 is an RLC EQ based on Barry Porter's original Trident A-Range design. Each midrange filter is comprised of a capacitor / inductor combination and a discrete amplifier stage. The High and Low sheving bands have a gentle first order (6dB/oct) response. The difference in use between the "Barry Porter EQ" and the TFPro P9 is the difference between "thinking" and "feeling"... respectively (EDIT for Terry -see below). YMMV Post by: compasspnt on January 22, 2009, 09:29:19 AM Manual? Post by: yeloocproducer on January 24, 2009, 03:09:12 AM Post by: livingstone on January 25, 2009, 01:29:08 PM i'm curious to know what kind of ICs have you choosed to build your BP eq ? Post by: Greg Reierson on January 25, 2009, 03:46:49 PM
I can't speak for Brad, though I think I'm using the same opamps that Frank used in his EQ. The master cut/boost are LME49710s, the output is an ADA 797, the integrators and shelf buffers are OPA 134s and the rest are 5534s. GR Post by: compasspnt on January 25, 2009, 04:06:17 PM Post by: Viitalahde on January 25, 2009, 04:08:02 PM Unfortunately, they really need higher voltage rails to operate at their best. I'm currently loving them @ +/-24v, but I'm thinking I could try +/-22v for the BPEQ. This would keep a few doors open for nice IC's to use for the filters - such as 5534, LME49870 and some others. AD797 I couldn't try, which is a pity. Of course I could power up the I/O at +/-24v and the rest at +/-15v, but it seems like a little bit of a hassle. |