EP-PRE revisited

[Doug H]

here it is in action, crappy webcam mic, middle of the night volume etc...1 minute of pointless noodling

http://www.youtube.com/watch?v=2rDMxQy5eB4" onclick="window.open(this.href);return false;

Seems to cop a bit of that evil sparkle.

[leadguy]

That sounds pretty good to me even with the bad recording.
Something is a bit noisey.
Nice playing and timing as well.

[Doug H]

thanks, ya my amp hums like a banshee. Hopefully not for long.

[Doug H]

man. I'm totally digging this little box. I don't know if it's the FET or just boosting the front end of my amp that's realling me in, but I"m gaving a hard time turning it off.

I wonder how hard it would be to make a 6 band with 6 FET preamps. No opamp, just 6 pipes.

[Xplorer]

hello guys.

something i've often wondered is : how did eddy manage his echoplex, to have his tone but without the noises coming from an echoplex ?
i have two echoplex, so ... i'm interested ! one isn't repaired yet, and the other one : i checked perhaps everything, replaced all the electrolytic caps, resistors etc ... and it's less noisy but ... with the volume pot at 3, the echo is as loud as the signal. over 3 it's really noisy : at 10 , it's like an amplified vacuum. did eddy set his echoplex volumes on 10 ? i don't understand. for me, it's not useable.
also, my echoplex feature the later schematic, and the preamp is a bit different from the early one, so i guess i'll mod it and add this cap between the 100k and the 1 M for example ... and the rest.

i'm also wondering what exact parts to choose for a separate echoplex preamp, after C4, and where this ep3 preamp circuit is supposed to end ?! does this 220k going from the ground to C4 and the 100k resistor plays the role of the 500k record level pot ?? why not a 500k pot then ? and after that, still in the direction of the output : how should i wire the volume pot and between this 220k and the output/volume pot, why is this a 100k ( R6 ) and another 100k ( between the first or third lug of the pot and the output lug ) when on the early ep3 schematic i see a 220k and a 100k ? do you see what i mean or am i not very clear in my explanations ?

i'm asking that because all i see on internet about some echoplex preamp clones feature wrong stuffs and wrong volume pots wiring, impedance stuffs etc, according to peter.

also, the ep pre for example has 18 volts. on my echoplex, there are 22 volts coming into R4. and it's 13 volts after R4. if 13 volts is needed, i guess that i could simply use 18 volts, but change the value of R4, to get 13 volts... am i right ?

[leadguy]

What you are describing is not really a normal Echoplex and it's not really a question of what Ed did because a Echoplex with no issues just works.

My Echoplex is basically noise free and there are quite a few Youtube videos demonstrating normal Echoplex operation, do a search.

http://www.youtube.com/watch?v=MXLu_qlrsJQ" onclick="window.open(this.href);return false;

http://www.youtube.com/watch?v=scEhxceYgFA" onclick="window.open(this.href);return false;


Ed's EP-3's were brand new in 1977 and were basically brand new for the VH1 recording.

If you don't know much about FET circuit design then look around at what other FET preamp designers do

http://www.till.com/articles/GuitarPreamp/" onclick="window.open(this.href);return false;

The EP-3 preamp IS ONLY A COMMON FET CIRCUIT and not some magical thing designed by tone elves at the north pole.
FET preamps can be powered by a range of voltages and the voltage used in the EP-3 FET preamp is probably just a voltage compromise that meshed well with the rest of the EP-3 design.

[Xplorer]

thanks. yes , my echoplex isn't as silent as this one, but close. this echoplex in the video is played with the echo volume set at the same volume as the original signal and i'd be curious to hear it with the echo volume at max. mine does too much noise when i increase the volume of the echo.

i admit , my echoplex certainly has a problem, and i don't know how to figure it out. i already checked everything i could, and replaced many things. the only wierd thing is still the way it is wired near the motor : it's like another version compared to the schematic .
please, may i perhaps see a picture of yours, in this area ? in this case i could perhaps leave you my email through pm ?

did VH set his echoplex with the signal volume at max just before it decrease when the echo gets louder than the signal with the echo volume pot ?

about the preamp, yes, i'm discovering it little by little but for now it'd be great if i could experiment the same wiring and layout with no potential confusion, so i'd have a nice reference.
for the voltage, ok, i get it thanks.

it's probably off topic but if something seems potentialy a source of noise in this area i'd be glad to know something. but logicaly, my preamp works maybe nicely i guess if the dry signal isn't noisy, and the problem is on the echo circuit, that shouldn't be noisy when its volume is increased.

i should perhaps temporarly disconnect the heads board, to see if it still has some noise , leaving just the preamp board playing the dry signal. this could be a good test , right ?
i'd like to see what you mean with this van halen tone.

[leadguy]

"The Echoplex in his rig was set with the delay slider positioned around 10, the echo sustain control turned all the way down, for a single repeat, the echo volume control only slightly up and the effect switch set to Echo position (rather than to Sound on Sound). This generated a long delay (longer than a slapback, between 100ms to 150ms) that basically thickened up his guitar tone."

Ed's Echoplex settings above are from the EVH Guitar World interview 2007.

1 Echoplex for things like RWTD with the above settings.

2 Echoplexes for ATBL http://forum.metroamp.com/viewtopic.php?f=16&t=17343" onclick="window.open(this.href);return false;
A 100 ms and a 300 ms (approx) delay.
Both set for 1 repeat.


Here is a photo of Ed's Japan 1978 Echoplex settings.
Both Echoplexes have around the same settings, meaning that each Echoplex was on 2 separate amp/signal paths.
Ed used to change to a different set of amps for Eruption and one of these Echoplexes is in the signal path of these set of amps and the other Echoplex is in the signal path of another set of amps.
So Ed had an Echoplex with the same settings at all times in his signal path no matter if he was using amp setup number 1 or amp setup number 2 and it was good for backup purposes because if one Echoplex stopped working then he'd still have another Echoplex to keep on going.
But, Ed might have set the Echoplexes up for different delays when playing ATBL live, I don't know for sure, but one delay will be enough to get through ATBL in a live setting even though on the record their are two different delays.



To diagnose a Echoplex problem is a hard thing to do and there are dudes that specialize in it.

Don't know if these will help.

EP-3



EP-3 with compressor board



My Echoplex is a EP-4 which isn't much good for EP-3 photos.

[Xplorer]

very cool ! thanks. i endly understand why ed's tone wasn't noisy with his echoplex. i also understand a new way to diagnosis my echoplex, like i told before. yeah, if by hance you see such pictures i'd be glad to see it, and on my side anyway i'll re start my echoplex work ( cause i begun to be tired of working on them, months ago )

i hear that ed also used two echoplex in the same chain to boost something. actualy i didn't try this yet ! lol
are his echoplex known to be the early ep3 or the later ep3 ? cause the preamp isn't exactly the same, and the ep pre is based on the early one. mine are later preamps though one of them has a black chassis. i'll mod them to the early specs, if i like the preamp clone i want to build in a pedal. it shouldn't be difficult.
still looking for some infos on the ep pre pedal version in fact, as it's supposed to clone the ep3 preamp faithfully. and that's what i want.

[leadguy]

Ed's EP-3 Echoplexes are from early 1977 when the Echoplex logo changed to a wider "Maestro Echoplex logo" http://forum.metroamp.com/viewtopic.php ... 8&start=30" onclick="window.open(this.href);return false; and interestingly this is the time (early 1977) when some EP-3's (and EP-4's) were sold with an additional compressor board which is very similar to a MXR Dyna-Comp compressor.

The early 1977 EP-3's are around the 255xx serial number range http://www.mtcom.jp/~schematic/effects/ ... -28591.pdf" onclick="window.open(this.href);return false; http://www.schematicsunlimited.com/down ... ematic.pdf" onclick="window.open(this.href);return false;

[Xplorer]

thanks for the added pictures.

i think i've found this early preamp board, on this special solid state ep2. and you can compare with my own preamp board which features the traces. so EVH maybe had the later version which is supposed to sound less good ? not the one described by the ep pre ?

[Good Guest]

Well you see this is the biggy question ..which one did Ed have?..... the two ep3 versions not counting the mystery compressor will sound differant due to the bypass cap on the source of the fet...one will have more gain and low end the other will have more sparkle high end and less gain....Then there are the imitator pedals.....the ideal imitation ep3 would have a switch for the 2 differant sounds...then Eddie had another ep3 ..same or differant? No one knows..So yeah you got all these imitations out in the market and they don't even know what to imitate...throw a compressor into the mix and ya all been sucked in bigtime , getting furthur away from the tone, bying into the hype In other words ..stick to the real deal unless you know what yer doing. Some one should put out an ep3 pedal and call it the tone mangler. add starch to thicken

[Xplorer]

which one has more gain and low end, and which one has more sparkle high end and less gain ?
ok, that's what i'm gonna do : one or two echoplex preamp clones, with some switch for this bypass cap.
But in fact, i don't try to emulate VH's tone, i was just curious. In the beginning, i just want to know more about my real deal echoplex, and i want to throw one of these preamp in a pedal i'm building, which is a good fuzz to my ears. it sounded different, with the echoplex after the fuzz, that's all, and it could be fun to have two pedals in one for different prupose, no matter if it's the real stuff eddy used or not, totaly.
about the ep4 compressor, all i heard is that the ep 4 didn't sound as good as the previous one, and peoples tend to remove this compressor.

[Good Guest]

which one has more gain and low end, and which one has more sparkle high end and less gain ?

The one with just the 3.3k on the source of the fet is the one with more high end sparkle and more tube like in quality of tone , and less gain ....the one with the .022 bypass cap in paralell with the source resistor is more solid statey with plenty of low end boost...and is typical of todays fet boosts, and provides more gain.

I wasn't making any referance to you being an evh imitator.I was just pointing out the pedal makers are the ones that are swaying away from what is and is not real. The best bet is an actual ep3....with or without a dynacomp.

[Xplorer]

sure, i know you weren't doing this reference. i just explained my interest and my purposes.
something that is hard to duplicate, is the texture of the echo in the echoplex, this thing is damn magic, and with this high end sparkle version of the preamp, it's really great.
the only thing i'm not totaly sure, is how i should design/copy this preamp, after C4. why this 220k ? why not a 500k pot ?
i think i'm gonna breadboard it and simply test it, but i saw all these clones out there, and they all seem to have some differences from the real deal, like if they didn't know how to do, trying to clone the ep pre, wrong with the 500k pot. if anybody ha some clue ..