Another Electro Voice Interface D/Sentry VI thread.

[derik736]

Ok, found it

 

[PeterSchut]

An update after almost a year

Hi Forum.

I thought I shared some updates.
The system is still running great and does this set rock.

I made an upgraded EQ with the original 6 transistor design but added an over the top push/pull power supply and a new enclosure (see picture)

I have also added 2 ceiling speakers and two upfiring Dolby Atmos speakers.
They use Beyma 5"LF/MF dtivers and an EV T35.

So I am running Atmos 5.1.4 driven by a Denon AVR-X7200W (they only power the 4 top speakers and pre-out to the 7 channel power amp (bi-amp tho front.

Cheers

 

[PeterSchut]

some measurements of this old EQ

I have attached some Audio Precision measurements of this old EQ with the new supply.

I have not changed anything to the basic layout and components with the exception of replacing the Electrolytic input and output cap (replaced by 3x 3µ3 Wima and the 4 resistors that define the boost frequency (as the original unit was an Interface B version.

I removed all power supply components and switching options and added a class A power supply +/- 12V.
The input output wiring is now direct without going through the tape switch and also the filter settings are out. just the flat response is used

The channel balance is perfect within 0,05dB (see zoom of freq. response)
The FFT shows -110dB harmonics @ 0,5V input, and -105dB hum @ 50Hz

Pretty impressive for such an old design

 

[don3128]

Hey Peter, I must say this has been a most interesting read. I own a pair of 'D's and will not be looking for any other speakers for a long time. I am currently running mine Bi amped through a Yamaha SP 2060. This unit has the capability to almost dial up any parameter for EQ and crossover you wish. Prior to this setup I ran the speakers through the EV C/D equalizer and a rotel amp and loved it. Now I run it through 2 old BGW 750B power amps rated at 225 watts with no EV EQ. The sound is amazing and "loud!!!!" I have tried to simulate the SP 2060 with what info you have provided in your findings of the EV EQs. The results are stunning. My reason for contacting you is regarding the VMRs are you aware that the magnet arrangement is identical to the 12inch woofer of the 'D's and that a basket from any 12 inch ev driver should fit straight on and it should be able to be reconed pretty much the same as the woofer. The voice coils would need to be checked for a match. I say this as it is a lot easier getting hold of the VMRs than it is the woofers. So as a result of your thread I am on the search for some VMRs I have a pair of the horns from a pair of Sentry IIIs that I own. BTW the Sentry IIIs sound horrible compared to the D's. Thanks again for all the effort and info gathered.

 

[PeterSchut]

Hey Peter, I must say this has been a most interesting read. I own a pair of 'D's and will not be looking for any other speakers for a long time. I am currently running mine Bi amped through a Yamaha SP 2060. This unit has the capability to almost dial up any parameter for EQ and crossover you wish. Prior to this setup I ran the speakers through the EV C/D equalizer and a rotel amp and loved it. Now I run it through 2 old BGW 750B power amps rated at 225 watts with no EV EQ. The sound is amazing and "loud!!!!" I have tried to simulate the SP 2060 with what info you have provided in your findings of the EV EQs. The results are stunning. My reason for contacting you is regarding the VMRs are you aware that the magnet arrangement is identical to the 12inch woofer of the 'D's and that a basket from any 12 inch ev driver should fit straight on and it should be able to be reconed pretty much the same as the woofer. The voice coils would need to be checked for a match. I say this as it is a lot easier getting hold of the VMRs than it is the woofers. So as a result of your thread I am on the search for some VMRs I have a pair of the horns from a pair of Sentry IIIs that I own. BTW the Sentry IIIs sound horrible compared to the D's. Thanks again for all the effort and info gathered.

Hi Don3128,

The Yamaha looks a bit like the EV DC1. And indeed this can be used to dial in the required 6dB boost. According to the original designer D.B Keele from EV you need a 6dB @ 31Hz boost with a Q of 1.9. If that can be selected in the Yamaha it will be a perfect match.

I wanted to avoid any digital processing (even though this can be very good nowadays) as since early this year I am also back to using vinyl and I am so impressed how good this can sound (much much better than CD) that I want to stay pure analog all the way.
I might consider a nice analog parametric equalizer like the Avalon design AD2055 to tweak some room issues but not digital.

With respect to your remark on the VMR, I am not sure I understand you.
yes the magnet and voice coil diameter are identical to the woofer but I don't see how that would help making a new Interface D woofer.
The length of the VC is most likely different and even in the VMR there are 4 different voice coils. I asked my contact at EV and he mentioned that an EVM12L that has the same magnet and basket could not be turned into an Interface D woofer. The 2.5" VC of a VMR has a DC resistance of 8,5 Ohm (pro 5 Ohm) and the DC resistance of the Int D woofer is 3,5 Ohm.

I would love to have a spare D woofer set for sure

I still have two spare sets VMR but these are the pro ones that are very different from the Intf D ones. Although matching them with the ST350 is possible.

Could you please explain again what you want to achieve?
Cheers.

 

[totem]

don3128
Sentry IIIs sound horrible compared to the D's

Likely to draw a few contrasting views if not comments from Sentry III owners, incl myself.

 

[absolve2525]

Yeah, I sure haven't heard Sentry IIIs sounding horrible! Come on now, all big vintage EVs rock! Peter, I thought I recalled you saying pro VMR were interchangeable with Interface D? Is this not the case?

 

[PeterSchut]

Yeah, I sure haven't heard Sentry IIIs sounding horrible! Come on now, all big vintage EVs rock! Peter, I thought I recalled you saying pro VMR were interchangeable with Interface D? Is this not the case?

The funny part is that in isolation the pro and big hifi VMR (there is also a small HiFi version that is a completely different animal) measured very similar with the gain reduction dialed in.

But in the system I had to tame it a bit more and increased the series resistor from 5 Ohm to 6,8 Ohm.
So that is what I use in my Center and Surround channels.

 

[fishondwan]

Likely to draw a few contrasting views if not comments from Sentry III owners, incl myself.

HOGWASH !

Your Sentry III's MUST have an issue or two (or the source) . I love the D's but the Sentry III's hold top honors in my house.

BTW Peter that is a REALLY cool system you have there !

 

[PeterSchut]

Yeah, I sure haven't heard Sentry IIIs sounding horrible! Come on now, all big vintage EVs rock! Peter, I thought I recalled you saying pro VMR were interchangeable with Interface D? Is this not the case?

Hi absolve,

Yes the VMR are interchangeable in an isolated test. But combined with the ST350 i found that i had to tame them a bit.
Not sure why but in my center and surround speakers I used 7,5 Ohms in series in stead of 5 Ohms.
The DC resistance of the Int D VMR Voice Coil is 8,2 Ohm with 95 turns while the DC resistance of the Pro VMR is 5,3 Ohm with 69 turns.

Cheers,
Peter

 

[Khaefeli]

Thank you all for the great thread. I got the d's just a month ago and i'm astonished by the sound of these speakers.
Unfortunately i got them without the original woofers.
Does anybody of you know how the woofer is called or out of what parts he is made?

 

[PeterSchut]

Thank you all for the great thread. I got the d's just a month ago and i'm astonished by the sound of these speakers.
Unfortunately i got them without the original woofers.
Does anybody of you know how the woofer is called or out of what parts he is made?

Hi Khaefeli,
Finding the original woofers is near impossible. They are just not there.
They look like an EVM12L with foam surrounds but are very different.

What kind of woofers are in your "D's" now

 

[Khaefeli]

Hi Peter
Currently i dont know what woofers are in them.
But i know the person who has put them in and i'll ask him as soon as i can.

Do you know if the original woofers would improve the sound or if other woofers are also as good as the original ones.

 

[PeterSchut]

The D is tuned with the original speaker (812-8951) and I think that it will be hard to replace it with something else.
I investigated the Beyma 12BR100 (not in production anymore) and that would do quite well with modification of the filter. The beyma is quite a bit less efficient.
The Beyma 12BR70 would fit even better but is a less rigid speaker with 125W power handling. The nice thing is that this speaker will do great by just removing the 2,5 Ohm in series and leave the rest as is. It will be approximately 2dB softer than the EV and that is quite an easy mod for the mid/high section.

I am curious what is placed in yours

 

[Khaefeli]

The D is tuned with the original speaker (812-8951) and I think that it will be hard to replace it with something else.
I investigated the Beyma 12BR100 (not in production anymore) and that would do quite well with modification of the filter. The beyma is quite a bit less efficient.
The Beyma 12BR70 would fit even better but is a less rigid speaker with 125W power handling. The nice thing is that this speaker will do great by just removing the 2,5 Ohm in series and leave the rest as is. It will be approximately 2dB softer than the EV and that is quite an easy mod for the mid/high section.

I am curious what is placed in yours

So, unfortunately the person who knows which woofers i have, doesnt writes me back. -.-
But i'll call him soon.
So if i would want to use the Beyma i would just have to plug out the 2,5 Ohm in series or how's that going?
Sorry for the maybe dumb question, but i'm kinda new in that hi-fi thing.

 

[PeterSchut]

Indeed, you take the 2,5 Ohm out and replace with a wire (or short it) and use the Beyma
But before you do that check what is in there. take the woofer out or take a picture via the port in the bottom with your phone.

 

[flat-eric]

Hello, i bought my d's in august and love their sound (didn't expect that did ya? )
But the seller only had one of the Ev logos that's supposed to sit on the grills. Is there anywhere you can get one of those?

 

[Khaefeli]

Hi Peter
Do you mean I should take a photo of the woofer just from outside?
Or is there a port through which i could see the woofer from the back with the magnet?

sorry for replying so late, had many exams last week.

One last question. Do you have any recommendations how to enhance the speakers or do you know a good amplifier for the D's?

 

[Khaefeli]

hi
I just recognised that, when i push the lever for environment control, of the right speaker, to 1/4 it has less highs. In the manual it says it should have more highs. Also the other speaker has more when i do so.
Does anybody of you know what could be the problem?

 

[BobbyBluz]

If anybody has a pair of Sentry III's and thinks they sound horrible please let me know and I'll come get them from you. The ones I have in my studio are powered with a BGW 750B on the bottom and 250C on top using the SEQ box. Amazing speakers!!!