Can one make a Quad Eight 310 500 EQ clone if the schematics are available?

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PhilipMarlowe

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Hey there,

I'm relatively new to the game. I've built the Sound Skulptor MP573 and realized how much fun it was after the initial fear of destroying sth accidentally ( I haven't electrocuted myself yet, so knock on wood!)
It really is like knitting for dudes.
I'm interested in making my own clones since alot of stuff isn't available in kits anymore from the original makers like Peter Purpose's 1084 LAZ EQ or the Helios in 500 series format.

There seem to be schematics for the old Quad Eight 310s which seem to be hidden gems, which no one has cloned yet. Unfortunately the new Electrodyne 511s only have two bands and different EQ points, not making them real replicas and not as useful on busses I presume.

However my knowledge of electronics is very limited, if not downright newbie so I'm wondering if it really is as simple as printing the schematics on a 500 Series PCB board and adjusting the needed voltage to fit the format.

Can someone experienced tell me if it's at all feasible?

Thanks guys, love this community!
 

PhilipMarlowe

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Apparently you can buy them or I could ask some forum members who have them. I’m only interested in the 310 Eq though
 

abbey road d enfer

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PhilipMarlowe said:
Apparently you can buy them or I could ask some forum members who have them. I’m only interested in the 310 Eq though
You're asking for help; don't expect members to also do the search, and much less, pay for the schemos.
 

PhilipMarlowe

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abbey road d enfer said:
You're asking for help; don't expect members to also do the search, and much less, pay for the schemos.
take it easy man, i was just asking a general question, not asking you to buy schematics. Jesus...
 

Gold

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The 310 uses rotary switches. The hard part would be copying the multi tapped inductor. Cinemag may have the original drawings. It’s similar to the  712. There are schemos floating around for that.
 

Flundran

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Regarding inductors, one approach is using commercially available single inductors instead of a custom multitapped one. Depending on what values are needed of course.
 

PhilipMarlowe

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Flundran said:
Regarding inductors, one approach is using commercially available single inductors instead of a custom multitapped one. Depending on what values are needed of course.
I’m very new to the diy game. Is there a sonic difference between inductors that are single vs multi or is it purely due to the switches and how it’s used?
By the way, I found a low res schematic of the 312, which seems to be the same as a 310 with the fader/pre right? Not sure what these two guys are on about but I’m asking a simple question if making a 500 series clone of the quad eight eq is feasible for a newbie like me. No need to get your panties in a bunch. 

 

PhilipMarlowe

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abbey road d enfer said:
With EQ's, the main obstacle is potentiometer availability. The rest is trivial.
Can you post a schemo?
Unfortunately pretty low res
 

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Gold

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pucho812 said:
doesn't orphan audio own quad eight as a brand these days?

Yes AFAIK. That doesn’t prevent anyone from copping the circuit. You just can’t call it a QE310. It could be an XX310. Cinemag might not sell you the inductors though.
 

PhilipMarlowe

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I found a more legible schematic for the 310 from a friendly recording engineer.

Would a 500 series clone even work if api 500 is only 16v?

1/2
 

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gridcurrent

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PhilipMarlowe said:
Would a 500 series clone even work if api 500 is only 16v?
yes.
the Q8 310 is based on their AM4 discrete amplifier which is compromised at lower supply voltages.
the AM4 also lacks internal dominate pole compensation which may well be the reason for "bandaids" on the 310 including the Boucherot cell.
if an AM4 type discrete amplifier is desired, look at the VERY similar gain block in the UREI Mod-One console, which does have internal compensation.
not a substitute for the internal compensation, a simple series resistor but higher than 27 ohms will ensure stability.
consider the time tested 5534 for a 500 based package.
 

PhilipMarlowe

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gridcurrent said:
yes.
the Q8 310 is based on their AM4 discrete amplifier which is compromised at lower supply voltages.
the AM4 also lacks internal dominate pole compensation which may well be the reason for "bandaids" on the 310 including the Boucherot cell.
if an AM4 type discrete amplifier is desired, look at the VERY similar gain block in the UREI Mod-One console, which does have internal compensation.
not a substitute for the internal compensation, a simple series resistor but higher than 27 ohms will ensure stability.
consider the time tested 5534 for a 500 based package.
Thanks for the reply.
Excuse my Greenness but are you saying it’s easiest to use the UREI and build them into a 500 PCB or are you merely referring to the topology of the old urei?
Also any tips on the basics of diy electriconics? I have very limited knowledge unfortunately
 

gridcurrent

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PhilipMarlowe said:
Excuse my Greenness but are you saying it’s easiest to use the UREI and build them into a 500 PCB or are you merely referring to the topology of the old urei?
the UREI topology is stable.
unless you like the hassle of discrete amplifier builds,
use 5534/5532's.
 

Whoops

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PhilipMarlowe said:
I'm relatively new to the game.

I'm interested in making my own clones

However my knowledge of electronics is very limited

With limited electronic knowledge you will not be able to do this.

Your questions are also so basic that you should be thinking in something else to do that would fit better your present knowledge.

There's a lot of EQ's already in 500 series format and normal rack format, you should try one of the projects that is already developed here in the forum and has an help thread already.

EQ's in 500 series format theres, helios 69, SSL 4k E, Neve 1084, API 550, Neumann W491, and much more...
 

fazer

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The dual stacked 11 pole switches will be a hard source but not impossible.

Have you played or Listened to this EQ?  Just wondering what drew your attention to it.
 
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