Ecoplate amp electronics

[Rob Flinn]

I used to have an ecoplate 2 which I got froma guy called Paddy Kingsland who was part of the BBC Radiophonic Workshop & he did music for Dr Who and other film & tv stuff.  Loved it but I swapped it and a compressor for my MCI console.  I now have a valve EMT 140 mono but it's in storage and needs some TLC.

The ecoplates are good, they refined some of the weak points of the EMT like those clips that break etc.    Also all the electronics are very serviceable.    The box is slightly bigger than the EMT too.

 

[dmp]

I've heard that EMT used cold rolled steel and would reject about 50% of the plates due to poor sound.
Jim Cunningham used stainless steel for the plate
I heard the ecoplate compared to an EMT but it was a long time ago. Similar, both sounded great, but you could tell the difference.

 

[JohnRoberts]

Now you guys have me thinking of just leaving it as it is.
The phantom powered DI I have now works fine - Stewart Audio ADB-4. I have the preamp and mixer next to the plate but I could bring them into the control room.

I could not find any specs on the Stewart Audio ADB input impedance...

At Peavey back in the late 80s I designed one active DI (EDB-1), probably still being sold. It could be powered from mic input phantom power.

It was not crazy high input impedance but 3M ohm resistive (IIRC) which is probably reasonable for piezo termination.  It uses a TL072 bifet op amp so respectable audio performance (IMO, but I like all of my designs). 

The discrete jfet buffer I described could be made even higher input Z, but the commercial product EDB-1 has more practical drive capability.

JR

I did do some tests last night on the hum and it doesn't seem to be coming from the electronics. Ambient noise from the environment picked up by the plate / pickups.

 

[Rob Flinn]

I've heard that EMT used cold rolled steel and would reject about 50% of the plates due to poor sound.
Jim Cunningham used stainless steel for the plate
I heard the ecoplate compared to an EMT but it was a long time ago. Similar, both sounded great, but you could tell the difference.

My ecoplate always sounded brighter than any of the EMT's I've used.

 

[dmp]

I could not find any specs on the Stewart Audio ADB input impedance...

It is discontinued and they kindly sent me a schematic. It looks to have a similar design.

 

[fazer]

My ecoplate always sounded brighter than any of the EMT's I've used.

That stainless is a brighter sound.  Different kind of brightness as well.  I’m sure an FFT would show a different series compared to cold roll steel.  In the 80s,  tape would change the top end sound of playback.  I always wanted to get more top.  In this digital age I’m  always being cautious with top end.  I have a 140 tube EMT.  It has that rounder or less highs so I would eq it.    It’s a stereo but also in storage and will need gone through I’m sure when brought back to life.  I’m in the process of getting a house sold so no urgency to bring it to life anytime soon.  I have thought of keeping it original, but would add some pizo pickups with something like ecoplate type outputs as well.  The idea of using a DI with a micpre is a simple way to do that.  Tube electronics will have a higher noise floor then the SS output amps.   

Plates need to be in a quite room as well.  I once listened to a producer chew out the band leader in the echo plate room  through the reverbs acoustic pickup.  I Played it into the cue system for the musicians and we had a laugh but also the song got adjusted automatically more into the producers wishes.  It could have gone bad .   

 

[Rob Flinn]

I did the piezo mod to someones emt plate.  It really drops the noise floor.  I wish I'd kept the details on what components need swapping out in the amp.    The same friend bought Jims tuning gauge.  It was not very good in my opinion, & I found it easier to tune by ear.

 

[fazer]

I did the piezo mod to someones emt plate.  It really drops the noise floor.  I wish I'd kept the details on what components need swapping out in the amp.    The same friend bought Jims tuning gauge.  It was not very good in my opinion, & I found it easier to tune by ear.

did you modify the clips?  I have some original clips but worried what to do once they are used up.  I guess someone sells them on Ebay for a rape price but thats the American way.  No hurry here just wondering what you might do for clips. 

 

[Rob Flinn]

did you modify the clips?  I have some original clips but worried what to do once they are used up.  I guess someone sells them on Ebay for a rape price but thats the American way.  No hurry here just wondering what you might do for clips.

That's a good question, because I don't have any spares & I definitely have  at least 1 or 2 broken ones in my plate.  I did look at the ebay supplier but they are outrageously expensive.