EV Interface D speaker questions

[rpeter46]

Hello,
I recently acquired a pair of EV Interface D speakers off the infamous auction site. It was a local pickup. I'm very pleased at their overall condition, including a ziplock containing original-style speaker cloth. Anyways, here's the part where I ask the collective for some insight:

1- Which Series of Interface D are these? No stickers or visible identifiers. Most likely a 'series I', then?

https://drive.google.com/open?id=1wzQ2p0HGM-mg1JdMWfjDNJlkoVD4udIW
2- After reading several other threads, I've noticed a difference. Here is a picture from another 'famous' thread of an exemplary restoration of this speaker on AK. I don't know whether to give credit, thanks, or to not mention someone else's handle, so my apologies for my ettiquette ignorance here.
https://drive.google.com/file/d/1LaJDf7cviK0oEa_KrAjz_78O_dnJL_w6/view?usp=sharing

Now here's mine. What is the significance of the removable "baffle" on the bottom? Leaves me baffled.... Sorry. I understand it's functionality. There's heresay about a baffle and the lack of an EQ box. Mine did NOT come with the EQ.
https://drive.google.com/file/d/1m8o-rM-i0809c1NZyCtSqLLnHQQ3OI5H/view?usp=sharing

3- Woofers. These reek of 'original to this here setup', but I have doubts based on the look of others on AK. Whaddaya think?

https://drive.google.com/file/d/1FLeolSssC5mRkud8x2hSa-CZZ9aFJZSg/view?usp=sharing
https://drive.google.com/file/d/1stp0lGHsjy-zi6fP-NqDFzGIPaSVRUnh/view?usp=sharing
Sorry about multiple topics. Just jump in on what you can address. Thank you!
Paul

 

[Coytee]

As I recall, the original D had a fixed port on the bottom. If yours is removable, then it might be the next series. (does it say Sentry on it or does it say Interface? Look at the plate on the front, near the switch) The Interface D and (I think) Sentry 6 were essentially the same design with some small changes (I think the port on the bottom)

My pair had an EQ so I'm not familiar with the newer versions.

Nothing there looks out of place to me but then, I don't know that I could recognize a woofer driver from a front view (other than the missing foam being a good clue!!)

If I recall, the drivers don't say much on their back side telling you what model number they are (mine were very sparse with regard to any useful information)

If you've never heard them in full glory before, they are a quite formidable speaker. Their -3db point is 28 Hz and I think they're rated at 106 db's at that level (foggy memory)

I'll see if I can attach some stuff for you.

 

[Coytee]

and the rest

 

[rpeter46]

and the rest

Thank you Coytee. Much appreciated for the literature!
Here's a picture of the front, with the tag from the back next to it.
https://drive.google.com/file/d/188u-DAQApjiyjBp66wM8naR4L323xGvr/view?usp=sharing

 

[Coytee]

Looks identical to the type of info mine had on them.

 

[rpeter46]

Can anyone identify the "Series" that these are?

 

[totem]

Am I correct in recalling the D's were designed to only be run with the EQ?
Or perhaps with the removable port on this example it was optional like the
Sentry III's since they also had a port blocking panel?

 

[MCM_Fan]

Can anyone identify the "Series" that these are?

I don't recall how many different "Series" there were (4 or 5?), but the brown baffle paint and brown grill cloth indicate yours are pretty early samples (Series I or II, I suspect). I had some that looked very similar to yours, with no identifiers as to the Series number. Wish I still had them. Best sounding speakers I have ever owned, very easy to drive, but also capable of handing a LOT of power.

A definite yes on the EQ. Electro Voice was very insistent that it must be used, and to my ears it definitely improved the bass. It was a very clever design and well executed.

Mine had two rectangular "ports" on the bottom. One that was always open and one that had a removable cover held in place with four wingnuts. I always ran them with that one covered, as that;'s the way they came from the factory. Mine didn't' come with the EQ, but I picked up an Interface B EQ and modded it to work correctly with the Interface Ds. It's a simple mod that involves swapping four resistors. I documented it in this thread:

http://audiokarma.org/forums/index....-voice-interface-d-restoration-thread.738842/

Which was first a victim of the Photobucket extortion virus and now postimg.org seems to have moved to postimg.cc, breaking millions of links to photos in forums around the internet. Sigh...

 

[MCM_Fan]

Your woofers are definitely original. Mine only came with one original woofer, but it was identical to the photos you posted (only mine was in far worse shape). AK member @GordonW reconed my original and built another one from parts (frame and magnet from a different EV model combined with the proper Interface D recone kit). They came out perfect.

 

[rpeter46]

I don't recall how many different "Series" there were (4 or 5?), but the brown baffle paint and brown grill cloth indicate yours are pretty early samples (Series I or II, I suspect). I had some that looked very similar to yours, with no identifiers as to the Series number. Wish I still had them. Best sounding speakers I have ever owned, very easy to drive, but also capable of handing a LOT of power.

A definite yes on the EQ. Electro Voice was very insistent that it must be used, and to my ears it definitely improved the bass. It was a very clever design and well executed.

Mine had two rectangular "ports" on the bottom. One that was always open and one that had a removable cover held in place with four wingnuts. I always ran them with that one covered, as that;'s the way they came from the factory. Mine didn't' come with the EQ, but I picked up an Interface B EQ and modded it to work correctly with the Interface Ds. It's a simple mod that involves swapping four resistors. I documented it in this thread:

http://audiokarma.org/forums/index....-voice-interface-d-restoration-thread.738842/

Which was first a victim of the Photobucket extortion virus and now postimg.org seems to have moved to postimg.cc, breaking millions of links to photos in forums around the internet. Sigh...

On the EQ. Can a "Interface A" EQ be similarly modded to correctly work like a "D"? Or is it a lot more work? I have a line on an Interface A EQ, and it seems to be the easiest to find.

Paul

 

[rpeter46]

Update. I refoamed the woofers, and they sound fantastic. Purchased an "Interface A" EQ from the bay, and have started into transforming it into a "D" box. Or at least I thought I was... The schematics and resistor information I have seen looks very different from the unit I received. Here I've posted a pic with some of the resistors called out, and you can see how it varies from the schematic. I'm quite sure there were 'variants' produced, but I'm having some trouble because of it.

https://drive.google.com/file/d/1clGyLWSugjrmTgSPIp7aUZ3-p2SWUi7E/view?usp=sharing

https://drive.google.com/file/d/12uL1-HrU3Z2T6fNecW1A70iqQ3qG4fEp/view?usp=sharing

 

[rpeter46]

Can anyone help me with this circuit?

 

[rpeter46]

bump.

 

[rpeter46]

Are there any hints or alternate schematics to help me with my Interface A circuit questions? Am I conspicuously missing something here? Thank you for any input.

 

[rpeter46]

One last try... I would really like to do something with this Interface A EQ. I heard that it was supposed to be relatively straight forward, and unfortunately, I'm just getting crickets... Can anyone give me a hand on this? Please and thank you.

 

[Coytee]

I'm lost/clueless.... but wanted you to at least know you weren't talking to yourself ...

 

[MCM_Fan]

One last try... I would really like to do something with this Interface A EQ. I heard that it was supposed to be relatively straight forward, and unfortunately, I'm just getting crickets... Can anyone give me a hand on this? Please and thank you.

Your Interface A EQ looks completely different than the Intferface B EQ I modded for use with my (sadly gone) Interface Ds. Is yours one of the older versions with the silver face plate? If so, I don't think you have the correct schematic and I'm not even sure if it can be modified to work properly with the Interface Ds.

Just for clarification here's some photos of the Interface B EQ I modded and recapped to work with my Interface Ds:

Does yours look like this?

Here's the inside:

And these are the resistors I swapped out:

I replaced these resistors with the 220K and 13.0K values as shown in the schematic you posted.

Again, if your EQ is an earlier version, that may not be the correct schematic for the EQ you have.

 

[sonofagun231]

Consider yourself lucky having those. I recall hearing these demo'd in E-Vs room at CES in Chicago many years ago. They were the most impressive speakers I heard that year and the designer gave a very lengthy and informative talk on their design. If I ever found a deal on a pair, I'd buy them in a heartbeat.

 

[rpeter46]

Thank you for the replies. I was feeling a little lonely there for a minute.

MCM Fan - yes, mine is a silver-faced EQ. Is it impossible to get "from here to there"? Sounds like you are suggesting that I cannot modify my silver-faced "A" EQ to become a "D"(within reason). Can you point me in the right direction for the correct schematic? Thanks!

Paul

 

[Coytee]

Dumb question perhaps.... could you just buy an active crossover biamp them and in the process, toss in several PEQ's to replace the factory EQ box??

(of course, if you could do that, the next question to me would seem to be...what values would you use for PEQ's??)