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

[Rob Flinn]

Jim Cunningham is a knowledgable & helpful person.

His plates were sold under the "ecoplate" brand. I have an ecoplate 3 which was the biggest version he did. It differs from the EMT plates in that the plate is made of stainless stell which makes it somewhat brighter. One difference that I see between the ecoplate & the EMT is that all the slight design problems of the EMT seem to have been ironed pout in the ecoplate.

Jim also sells a tuning gauge that a friend of mine has just bought to tune his EMT. We were in the process of tuning this EMT, but broke a clip, & are awaiting some replacements to continue. Therefore I can`t comment on the effectiveness of the tuning gauge, although it seemed straightforward to use as far as we got.

Jim also sells some piezo pickups. These pickups just look like the standard piezo transducers that are maybe 20mm in diameter. The EMT that these are going on is a mono valve version & to fit them requires some minor component changes to the amp. I believe they just have a higher output & therefore reduce the noise floor.

 

[MrZpliff]

Where can I find Mr Cunningham ?
I'm very interrested in those pickups !

 

[jensenmann]

Hejsan, Rob, could you please drop me a pm with Mr Cunningham´s email?
Thanks
:thumb:

 

[DerEber]

Interested in pickups too!!!
My 140 is very noisy.
:sad:

 

[Rob Flinn]

With regards to the replacement pickups. They do look identical to the ones here

(http://www.maplin.co.uk/Module.aspx?ModuleNo=3202&&source=14&doy=search

Although they may have been selected to have sympathetic specifications for a plate. They get glued on to the plate with a fast bonding adhesive. They are about 20mm in diameter. I`m not sure what mods you would do if you were using a transistor amp.

 

[hejsan]

Cunningham said:

> The pickups are piezo elements but it is
> important to choose one that has it's resonant
> frequency well outside the audio range. All piezo
> devices have a screaming resonance so this is
> very important. Also they must be mounted with a
> special conducting cement (to avoid ground loops)
> which we supply with our pickups.

His email:
fugalx [at] att [dot] net

Regards,
hejsan

 

[Dale Manquen]

Bimorph bender transducers - http://www.mouser.com/catalog/624/1322.pdf

Martinsound's spring clips are much stronger than the old EMT versions.

We used the adhesive sold to bond auto rear view mirrors to windshields - nothing conductive here. We did use a high-silver-content solder.

The bimorph can't resonate when it is bonded to the metal plate.

 

[hejsan]

[quote author="Dale Manquen"]Bimorph bender transducers - http://www.mouser.com/catalog/624/1322.pdf
[/quote]

Are you reffering to the "PIEZO CERAMIC BENDERS (ELEMENTS)" in the bottom table?

I've never heard the word "bimorph" before.

Which one in particular are you referring to?

Thanks,
hejsan

 

[Dale Manquen]

I don't have a sample of the Martech disc, but it seems like it was about an inch in diameter.

 

[Rob Flinn]

Yesterday I tuned my friend mono valve emt plate. We started off using Jim Cunninghams tuning gauge, but kept breaking clips despite following the instuctions to the letter. In the end we were beginning to run out of clips, so we opted to tune it slightly lower pitch than the gauge was indicating, which suited my friend because he didn`t want it to be particularly bright anyway.

Basically this gauge makes it so that if you tap the plate at the mid point along each of the 4 edges of the plate you get the same pitch note.

Obviously if you can tune a guitar then this is not difficult to do without the gauge. However the difficulty lies in tightening it enough without breaking a clip, which is very easily done.

I also fitted a low noise pickup also from Jim to the plate. This makes a very big difference to the noise floor. This mod also requires 3 resistors & 1 cap to be replaced/added. The amp then needs realigning. Like I said this makes a very noticable change to the noise floor.

 

[Sammas]

This is a great thread. Im considering building a small plate reverb out with an aluminum frame. Are there any disadvantages to using a smaller plate, other than shorter reverb times? I don't have the room for an EMT 140 sized plate.

This looks nice:

Has anyone considered using two drivers for stereo in/stereo out operation?

 

[MrZpliff]

Hi !

I've read somewhere that the plate should be thinner the smaller it is....
But why not just build it and try ? :grin:
It might sound great for some stuff, and you can probably EQ the send and returns to get a good sound. I'm thinking of building a spring-reverb myself for special effects... and for fun though I'm very pleased with my plate.

I don't think two drivers is a good idea ! Why ? I dunno :roll: but they will probably interfere with eachother in a bad way... besides you get stereo by using two pickups and you'll probably only send mono-signals to it anyway.

 

[haima]

rob - i had a similar experience with jim's tuning gauge - i broke a few of his clips while trying to reach the recommended tension... i ended up going for a slightly lower tension (still using his gauge to get it even) - sounds good, & no broken clips - i want to experiment up and down with the tension, as it really makes a bit difference!

i've also installed jim's piezo disc/bimorph pickups and made my own preamps based on jim's design (but with different opamps - OPA604+THAT balanced output driver). great improvement in noise floor.

 

[guy_4]

Hi Rob, Halma, Dale...and more !
I have the same experience as you with Jim Cullingham " unbreakable " clips for the EMT140 : they BREAK !
I also bought and used his gauge for tensionning the plate, but the clips break before the plate is correctly tensionned.... :'(
I must say I was quite surprised when it happened, I have read so many times that they could not break...
I've installed two of his new piezo pickups, and I built a new electronics section ( 1 driver + 2 preamps ) and it works very well, noise floor is much lower than the original TS162.
A friend of mine has just got 2 old mono tube EMT140's, I will visit him this week to see what can be done with them...
Also thanks to Dale for your valuable tech info !
Best,
Guy

 

[Rob Flinn]

That is one advantage of my ecoplate over the EMT140.  You would rip the clips out of the plate before they broke with an ecoplate.  However, that also means it is easy to damage the plate itself through over tightening  !!

 

[haima]

i have heard that you can deform the plate sheet from over tightening, in a way that will make it impossible to tension evenly in the future - might be an unsubstantiated internet rumor, but it does makes sense... perhaps it's a good thing the clips break (i've heard that's actually the way they were designed).

i wonder if anyone's tried a thin bronze/brass sheet... a "musical" metal...

 

[RayBlack]

We will try it with galvanized metal sheet, which was the cheapest to get, and 2 standard Piezos with their resonance at 6,8 kHz...An all DIY solution.

Will report back, with sounds and Pics.

Greets
Ray

 

[haima]

give it a go! show us how it sounds but build it in a way that you can "upgrade" to cold rolled steel or stainless steel at a later date.

a lot of the work is in welding the frame and adding the tensioning bolts. once you have that you could try different sheet material relatively easily providing you can get them cut to the same size.

the driver coil on my EMT140 is like a speaker voice coil that ends in a cone that is riveted (?) to the steel at one single point. you could bolt it on i imagine, that way you can re-attach it to different plate materials.

have you seen the DIY manual on Jim cunningham's website?

 

[guy_4]

Rob,
You wrote :"You would rip the clips out of the plate before they broke with an ecoplate "

How are they different from the clips that JC have for sale ?
I thought the Echoplate was designed/sold by JC....and I can assure you that his clips are breaking !
Can you explain more on this ?
Best,
Guy

 

[stitch-o]

http://www.prosoundweb.com/article/print/how_to_build_your_own_plate_reverb

along the same lines...