Anyone built the EMT-140 Tape Op Plate ? Sound Samples

[jensenmann]

Holy sh*t, that´s the way fooking coolest piece of DIY I´ve seen for a long time. Dear MrZpliff, you´re a hero. Where did you get your infos from?
:shock: :guinness: :shock: :guinness: :shock: :guinness: :guinness: :guinness: :guinness: :guinness:

 

[AnalogPackrat]

Excellent! :shock: I want one!

A P

 

[skipwave]

[quote author="MrZpliff"]Ok !

Here are some pictures of it.... but BEWARE, it's the worst kind of p*rn :twisted: with the guts spread all over. It's still under construction, so I'm a bit embarrased

.. now you're warned, have a look :green:

http://www.bitterend.se/plate.jpg
http://www.bitterend.se/mount.jpg
http://www.bitterend.se/plate-amp-chair.jpg
http://www.bitterend.se/amp.jpg
http://www.bitterend.se/driver.jpg

I'll make some soundsamples once I'm finished tweaking it. But as I said before... it sounds really good. I've EQ:ed the pickups with Gyraf:s Calrec, wich works really well, but feels like a little overkill[/quote]

What is the thickness of your plate?

Your's looks awesome! I love the mounting arrangement.

 

[MrZpliff]

It's basically the Tape Op plate reverb found here:

http://www.prosoundweb.com/recording/tapeop/plate/plate.php

the plate is about 0,5 mm thick, the frame is welded together (no, I didn't do it) from 40 mm square steel (not solid :grin: )
The hooks are for mounting ladders and other "safety gear for roofs" :thumb: so I don't think they'll break. I've tensioned it pretty hard, but I need to adjust the tensioning to get it more even. I'm also thinking about getting another driver, but this one works and it sounds pretty cool, so I dunno....

There's still some tweaking to do, but when I'm done I'll post some samples.

I've tried it on Congas = great ! and on horns = awesome, vintage sound !
also great on acoustic guitar. I will add a damping like the original EMT though, the decay time is pretty long, about 5 sec.
I'll also build a housing to keep some noise out of it, the thing is lika a giant microphone :green:

I don't have an original plate to compare with, but I think it sounds pretty close to the reverb heard on many 60/70:s records. I'm very much into that stuff, like soul, Stones, Bowie etc... etc..

The cost for the frame, plate and mounting is about 450 Euros. Most of it is for the work. The material alone I'd estimate to aroud 150 Euros.

 

[Dale Manquen]

Some of the things we learned while designing the Martech EMT upgrade might be helpful:
Place the pickup preamps close to the pickup amps. This minimizes the cable capacitance and loss of signal. We used a FET op amp with a bit of EQ and 20 dB of gain as a buffer, then fed this to a balanced line driver.
We utilized the EMT HF equalization - a boost on the high end to compensate for the mass of the plate.
When we got to a really clean sounding, we found that the EMT high pass filter really wasn't desirable. We had half-octave selection, but most of the scoring stages in Hollywood (which all use Martech-upgraded EMT plates) run them flat on the low end.
We used an amplifier capable of 30 watts peak.
With a +4 dBm reference level, the narrowband dynamic range at 1 kHz was about 130 dB. We had about +26 dBm peak output capability. When operating on our Neve VR console, the noise of the plate was about at the same level as the noise of the mix busses.
Your driver is clever, but I have a couple of comments. Is the post attached to the plate so that it can push and pull equally well? I would be inclined to have a cone on the top of the dowel, trying to create a point source.
We included a warble tone generator that could be used to inject a line level signal for setting the driver and pickup circuits gains. This isn't hard to simulate if you have a function generator with a VCO input.
I can't tell where you have placed your pickups for stereo, but they should be asymmetric.
If you do things right, the output from the plate should sound like clean music, not a steel plate. You may have a problem until you get a damping plate rigged because of your long decay time.

 

[yan_b]

can anybody give details about diy'ing the driver , it's looks like the conless driver mentioned in the tape-op article is very hard to find.

 

[MrZpliff]

[quote author="Dale Manquen"]Some of the things we learned while designing the Martech EMT upgrade might be helpful:
Place the pickup preamps close to the pickup amps. This minimizes the cable capacitance and loss of signal. We used a FET op amp with a bit of EQ and 20 dB of gain as a buffer, then fed this to a balanced line driver.
We utilized the EMT HF equalization - a boost on the high end to compensate for the mass of the plate.
When we got to a really clean sounding, we found that the EMT high pass filter really wasn't desirable. We had half-octave selection, but most of the scoring stages in Hollywood (which all use Martech-upgraded EMT plates) run them flat on the low end.
We used an amplifier capable of 30 watts peak.
With a +4 dBm reference level, the narrowband dynamic range at 1 kHz was about 130 dB. We had about +26 dBm peak output capability. When operating on our Neve VR console, the noise of the plate was about at the same level as the noise of the mix busses.
Your driver is clever, but I have a couple of comments. Is the post attached to the plate so that it can push and pull equally well? I would be inclined to have a cone on the top of the dowel, trying to create a point source.
We included a warble tone generator that could be used to inject a line level signal for setting the driver and pickup circuits gains. This isn't hard to simulate if you have a function generator with a VCO input.
I can't tell where you have placed your pickups for stereo, but they should be asymmetric.
If you do things right, the output from the plate should sound like clean music, not a steel plate. You may have a problem until you get a damping plate rigged because of your long decay time.[/quote]

Thank's ! that information is very appreciated :grin:

I've kept the cables from the pickups as short as possible, then into a JFET-amp with about 20dB of gain + a buffer amp. The line-signal is unbalanced, but very silent though.

When you speak about the HF eq, do you mean the driver-signal ?
I've changed the low-cut to about 130 Hz, 6dB per octave.
It's easier for me to cut the low-end, rather than boosting the high-end.

Concerning the driver: the post is glued (super-glue) to the plate, since i didn't want to make a hole in the plate before I had tested it.
This is just a setup for testing, really. I took an old Hi-Fi speaker and cut the cone off.... but it works remarkably well :!:

I'll make a new post from metal I think. I'll also make it cone-shaped.

The pickups are placed about an inch asymmetric along the x-axis and symmetric in y-axis... is that correct, you think :?:

I'm working on the damping... how thick is the original damping-material ?

Thank's again for the feedback ! :guinness: :thumb:

 

[MrZpliff]

[quote author="yan_b"]can anybody give details about diy'ing the driver , it's looks like the conless driver mentioned in the tape-op article is very hard to find.[/quote]

I nicked the idea from this site: http://www3.bc.sympatico.ca/gwolanski/Htheater.html

used an old speaker and superglued a post in the middle....
I'll work on a better one, but it really sounds pretty good

 

[Dale Manquen]

The driver equalization was a bit like the Record EQ on a tape recorder. Seems like the EMT instructions had an frequency response graph. We also had a slight lift on the high end. Using a rolloff on the low end isn't going to do the same thing. The adjustable low cut on the EMT amp was necessary to make that combination sound right, but like I said, the Martech version didn't need any cut.
You can use either pink noise or a warble tone to measure the frequency response.

We mounted the preamps within a couple of inches of the pickups on crossbars, using spiral spring coils of wire made from wirewrap solid wire soldered with silver-loaded solder to the pickups.

I don't recall the mounting dimensions for the two pickups. Maybe Lance Pottinger can measure the locations of his pickups. We glued the bimorph discs near the original pickup mounting holes, but they were clear of the holes.

There were two types of damping plates. The original plates were asbestos tiles that were glued to multiple mounting ribs. The glue died over time, and we had to reglue them with silicone glue. The newer ones were a single sheet of high-density Fiberglas that was 1/2" (?) thick. The damper could move from about 1/8" to over an inch. Once again, Lance may be able to give more details.

 

[hitchhiker]

I'll try to get the pick up and damping measurements during the week. The plate is behind a Hammond organ and some guitar amps etc. I had it apart a week ago to test some preamps that I did up for Soundarts Stutios in Texas. They sold me my new 3M m56 16 trk! The one that Dale designed! I could have measured things then! :sad: I do know that the
right side pick up is aprox 10 inches farther form the driver than the left
pick up. This creates more of an echo effect on the right side.

cheers,
Lance

 

[SilverhammerNZ]

I built a plate in the 80's, and used a speaker for a driver with a cone glued to the centre of the speaker, a small bolt was glued to the end of the cone (thread outwards) and this passed through a small hole in the plate and was secured with a nut the other side. It was obviously inportant to get the speaker centred. My plate also used hooks and not spring clips. The pick ups were the usual piezo pickups.

It worked just fine, even without a damping plate, I think I used to wedge foam at the edges to cut the time down, very elementary but it worked.

I have an EMT140 now, I always read with interest about the Martech upgrades.

Larry

 

[SilverhammerNZ]

I built a plate in the 80's, and used a speaker for a driver with a cone glued to the centre of the speaker, a small bolt was glued to the end of the cone (thread outwards) and this passed through a small hole in the plate and was secured with a nut the other side. It was obviously inportant to get the speaker centred. My plate also used hooks and not spring clips. The pick ups were the usual piezo pickups.

It worked just fine, even without a damping plate, I think I used to wedge foam at the edges to cut the time down, very elementary but it worked.

I have an EMT140 now, I always read with interest about the Martech upgrades.

Larry

 

[SilverhammerNZ]

I built a plate in the 80's, and used a speaker for a driver with a cone glued to the centre of the speaker, a small bolt was glued to the end of the cone (thread outwards) and this passed through a small hole in the plate and was secured with a nut the other side. It was obviously inportant to get the speaker centred. My plate also used hooks and not spring clips. The pick ups were the usual piezo pickups.

It worked just fine, even without a damping plate, I think I used to wedge foam at the edges to cut the time down, very elementary but it worked.

I have an EMT140 now, I always read with interest about the Martech upgrades.

Larry

 

[MrZpliff]

I've finally had the time to make some soundsamples of my plate.
Had to build a new driver as the old one broke down, which was great 'cause it sucked anyway :twisted:

http://www.bitterend.se/OLD-driver.jpg

Made a new one from an old VOLVO :green: car speaker, an Austrian "Ein Shilling" - Coin (before the EURO) some washers and a metal-post, which is now screwed into the plate.
All put together wit some slow hardening 24hrs epoxyglue.

New driver before the post was mounted:
http://www.bitterend.se/Driver-EinShilling.JPG

Soundsample - Piano: Dry - MixedplateNOEQ-MixedplateEQ-PlateOnlyNOEQ-PlateONLYEQ----
http://www.bitterend.se/PlatePiano.mp3

Some Congas
http://www.bitterend.se/PlateCongas.mp3

I've also made a damping for it. Thank's Rob Flinn :guinness: :thumb: for the scan:s !
The samples are with plate, let's say "Half-damped"

Edit:
http://www.bitterend.se/Damper.JPG
http://www.bitterend.se/Drivermounted.JPG
http://www.bitterend.se/Wholyplate!.JPG

 

[jensenmann]

:roll:
Holy Moly, if that´s the result I need to built a plate.:shock:
You guys make me sick, every two weeks there´s a new outstanding project to go for. :grin:
Thanks for the soundsamples
:guinness:

 

[MrZpliff]

[quote author="jensenmann"]:roll:
You guys make me sick, every two weeks there´s a new outstanding project to go for.
[/quote]

Well, this forum is quite addictive :razz: but !!
We'll probably have to start a "Prodigy Professional Forum DIY Gear anonymous" and start confessing... :green:
I'll add some more pics of this beast soon.

 

[jensenmann]

Kiira was so kind to send me the Plate DIY article. I scanned it and hosted it here:
http://groupdiy.twin-x.com/thumbnails.php?album=105

thanks and big hug to Kiira

 

[Dale Manquen]

Three comments:

1. Eye hooks come in welded and unwelded varieties. This application requires a weld to avoid pulling the eye open under heavy load.

2. When working with a plate, there are two velocities involved - longitudinal and transverse. Think about a Tsunami. The longitudinal wave is the speed of sound in water, which is about 1500 m/s or 3400 mph (nearly Mach 5 in air.) This is how fast you would hear (through water) the event that causes the Tsunami. On the other hand, the damaging energy of the Tsunami travels as a transverse wave, lifting up the surface of the ocean. This wave travels several hundred miles per hour, but much slower than the longitudinal wave.

For a steel plate, the longitudinal velocity is about 6000 m/s - REALLY fast. This is a characteristic of steel, regardless of how we apply the steel. We don't use this component in a reverb plate. It would be totally independent of the tension in the plate.

The component that we do use is the transverse or flexing component, which acts somewhat like the string of a musical instrument, but in two dimensions rather than just one dimension. Tensions, densities and stiffnesses all get involved in this case.

3. The use of microphones in the article, rather than bimorph contact pickups, would create additional problems, including a degraded noise floor. The Martinsound EMT upgrade with bimorphs had a narrowband noise floor 105 dB below peak level at 1 kHz. If you want those long reverb tails, you need to have a low noise floor.

 

[MrZpliff]

I'm more than pleased with my build. I haven't heard a real plate in action though, (only on record) so I don't have much to compare with...

it sounds great to my ears, so why bother ? :?

I've jacked the returns to two channels on my mixer so I can EQ them, depending on the song.
I usually cut alot around 200 Hz, and boost a little highs.

The "Volvo-driver" is rather heavy on the low end so I put a 6dB/octave filter in the send at around 700 Hz.

Sounds good enough to my humble and not especially golden ears.

Nice article Jensemann !

 

[hejsan]

I have the email of a guy that sells drivers and pickups and gives lot of info. A mr. Jim Cunningham who apparently designed and marketed a plate back in the days. I got mine a few days back. very detailed info.

regards,
hejsan