JHS Echotec ET-100 Mystery

[jim68000]

I've just acquired one of these:



It's a nice warm BBD delay. There's not a lot of info on the web about them, but apparently they were built by a Japanese manufacturer (not sure who) and rebadged as all sorts of things: the Melos DE-1 is possibly the same as is the Vantage EM-650.

The puzzle I have is what's inside:



Not the MNs, this bit:



There's a huge section of the circuitboard unpopulated. Anyone know anything about these units and what was supposed to go in here? Was there an ET-200?

[analogguru]

There's a huge section of the circuitboard unpopulated. Anyone know anything about these units and what was supposed to go in here?

The empty part with the 8-pin-chip is for a reverb-spring driver/ preamp (see Electra EP-200) and the part with the 16-pin-IC appears to be for a LED-display.

Was there an ET-200?

There was an Evans EP-100, an Electra EP-100 and there was an Electra EP-200 which used the same board.  (The part with the 16-pin-IC unassembled too.)

analogguru

[jbgron]

I acquired one of these a few years ago, mine is badged "Echorder" with no other branding.  It was OK sounding but I found a better use for the MN3005

[PRR]

What guru said.

Find pinout of LM3914. Fits the missing space (10 LEDs most on one side but 2 around the other side).

Not saying it IS a bed for a LM3914, there were many copy-cats, but likely something very similar.

[jim68000]

Most fantastic. Thank you all.

[ilcaccillo]

Hello,
this is an old thread but I have of these units to repair and I'm in desperate need of a schematic.

These are OEM analog delay units and were sold rebranded with a lot of different names and looks.
The schematic came in the second page of the Operation Manual.

These are some of the units that appear to be the same:

Melos DE-1
Stage DE-1
Better Echo Chamber EC-444
Echoman EM-150
Maplin Echorder EC444
Gemini Echorder EC444
Continental Echorder EC444
Phonic Echorder PH8020
Evans Echopet EP50
Evans Echopet EP-100
ERS ECH-802
PHONIA EC-400
Monacor EMM-1000
Monacor EMM-1200
Monacor EMM-2000
Mondivox Echo Chamber
BST Analogue Echo MCE 550
Europsonic ECH-802
Audiotek EC-555
Maplin Echorder E44
VANTAGE EM650
JHS Echotec ET-100
Electra EP 100
Redson DU-104A
Eli Analog echo SL-4040


Does anyone have the schematic for any of these units? Or the Manual?

Thank you so much

[BluffChill]

I'm not sure if it will help but I bought a half finished Maplin BBD kit on ebay a few years ago. I never finished it as I couldn't power it up. It did have the schem with it though. I'm not sure but it might be the same as the Maplin branded complete unit, which is probably the same as the Echotec. I posted a thread on StackExchange at the time:

https://electronics.stackexchange.com/questions/269144/charge-pump-9v-to-15v/269468#269468

And the schem:

[MrStab]

what would the LED display show? the level of each repeat, just the input, or something else? just curious.

[ilcaccillo]

I'm not sure if it will help but I bought a half finished Maplin BBD kit on ebay a few years ago. I never finished it as I couldn't power it up. It did have the schem with it though. I'm not sure but it might be the same as the Maplin branded complete unit, which is probably the same as the Echotec.

Thank you so much for your help, I will check that Schematic against my unit

[ilcaccillo]

what would the LED display show? the level of each repeat, just the input, or something else? just curious.

Input Clipping

[Mark Hammer]

Correct.  I have a Vantage unit with the Melos board.  These do not have NE570/571 compander chips in them.  That makes it mandatory to adjust the input level and initial gain to strike a balance between best S/N ratio and clipping.  Some will use a single LED to indicate clipping threshold reached, but a 10-LED display is better.

[sarakisof]

I know this is an old thread but i found you were talking about clipping leds on those units.
I found an old Better Echorder EC444. It had an issue by generating intermittent output signal.
After replacing the three 4548 culprit opamps with TL072s which i had in stock, it's in business again. Installed sockets so i can put new 4548s when they arrive.

It sounds nice but the Peak Led doesn't work correctly - or at all.
Replaced the C945 and after that it's always lighting dimly.

It uses LM18L15, MN3005, CD4001BE, 3 x 4558 opamps and A733, C945 transistors.
No schematic on web, i sketched a diagram tracing the pcb around A733, C945 and Peak Led.

What should i check around Peak Led, voltages etc ?

[PRR]

> i sketched a diagram tracing the pcb around A733, C945 and Peak Led.

That circuit only tells you about the power supply. Where is signal?

[sarakisof]

That circuit only tells you about the power supply. Where is signal?

This is the signal path. I left out many traces  like pin4 to gnd, 8 to V+, or there is a trace connected to the Repeats pot between 100k balance pot and resistor connected to polyester cap, etc., but those don't affect signal.
If you need specific paths tell me.



The other two 4548/TL072's pins are more related together and some of their pins are connected together through resistors and film caps. (Pin5 to pin8 through res etc.).
Second TL072's pin1 (out) is connected with its pin2 and through a film cap to pin7 (in) of MN3005. MN3005 pin3,4(outs) are then connected through resistors and film cap to second TL072's pin7(out). And second TL072's pin6 goes to 50K input pot through cap & res.

[PRR]

> If you need specific paths tell me.

It *can't* work as drawn; either mis-wired or incomplete. I still can't see how signal is supposed to get to the peak LED. If you don't want to say, or you understand it, that is OK with me.

[sarakisof]

There are so many traces and board is thick no phone's led transparent and it's really hard to work there. I must have been flipped the board hundred times already, thin pot's wires already broken. 
I thought about scannings both sides and then edit in Photoshop but started this way by sketching and wanted to finish like this.
I don't know if this is 100% correct but i did my best.

[sarakisof]

Any thoughts on what should i check about Peak Led's not working properly?