Echoplex ep3. Anyone knows it well ?

[Xplorer]

Some things that helped to restore this Ecoplex, and increas the sound quality , for some help if needed. Every details count :

-getting some new tape ( i don't have some lubricated tape, but the quantegy 478 works fine )

-making the bridge more straight

-cleaning everything

-cutting some of the old dirty pressure pad, to have some clean white coton left, but i'm gonna order some new one.

-changing all the electrolytic caps

-align heads, ad moving slightly the read echo heads till it gets the right tone to my ears, on a spot where high frewuency can be heard nicely.

-i've put something under the higher screw of the cartridge, to make it higher, and let the tape under it not touching anything

-some special oil on the motor axe, and on the capstan, and inside the pinch roller.

-cleaning the rubber of the pinch roller ( i used an ear coton stuff, with simple water on it, till all the black dirt would get off. the coton stuff between the roller and the capstan, turning the echoplex on, and pressing sightly.

-using alcohol on the heads to cean it

-using a demagnetizer on all the metallic parts

-changing te sustain pot ( frm tony at orbit electronic, who repairs echoplexs )

-setting the sos trimmer, on the side of the pots

-setting the record volume trimmer on the side of the motot ( some early models had this board on the side of the pots )

setting the recording volume pot on maximum.

on the sweet spots, with as much echo as dry signal, the hum is not too much noticeable,but it exists a lot, over this sweet spot. especially on the sos position.

here is a link ( just right click ,and save as, or "enregistrer sous", and you'll save an mp3 file, a short simple demo of how my echo plex does sound.

now that i've worked on the cartridge position, and that the tapedoesn't touch it anymore ( idn't realize it before) , the tape speed is more constant, and the sound is better.

http://dl.free.fr/gN2ivRrYR" onclick="window.open(this.href);return false;

please let me know what you think, it would help me...
in he beginning, i'm turning the volume from 3 to 9, you can hear the hum coming, and suddenly, i turn the switch on "sos", there you can hear a big bassy hum, don't like it. then i'm coming back to 3, and play some stuffs. later, you can hear a sample ( electric ladyland try ) that i play back , with the sos switch . the tape speed is more constant than that now.

thanks
Adrien

[demonufo]

I take it you know about this site;
http://www.regiscoyne.com/echoplex/" onclick="window.open(this.href);return false;

New tape is essential. It always made me laugh to see the prices people pay for NOS tape on ebay. Even old Ampex reels despite being unused are commanding good money, regardless of the fact that many of these old tapes will suffer from oxidation and leave your heads and tape travel path covered in sticky goo.
Quantegy 478 is a good tape, but BASF/EMTEC/RMG SM468 is even better, and biases fairly similar. I always found the BASF tapes to have been manufactured better than the Ampex/Quantegy stuff, and (although irrelevent with such a short stretch of tape) always spooled much neater than the Ampex, which suggests the cutting machines were set up better.

You can get proper pinch roller cleaner from certain sellers on ebay, and a few open reel enthusiasts. Have a good look at the pinch roller to make sure it isn't too soft, or too hard. If in any doubt over the condition, send it to Terry Witt (http://www.terrysrubberrollers.com" onclick="window.open(this.href);return false;) and he can make replacements for just about any rubber idler wheel.

If the unit has had a lot of use, it may benefit from having the motor stripped and cleaned too. You quite often find that the bushings in the motors of tape drives and tape decks dry up and end up scored. Polishing out the scratches on the shafts, and bushes can help keep mechanical noise really low. Worked wonders with a few of my old tape decks. (Used to have a real bad habit of buying and restoring open reel stuff, and then hanging onto it! )Make sure to re-oil on reassembly. A light machine oil is best. (Sewing machine oil, or food grade machine oil is good). I don't know about the echoplex motors, but many tape deck motors also have felt washers against the bushings to hold oil, which may want cleaning out with solvent and re-oiling.

[Xplorer]

thank you

yes, i did all this, though not opened the motor, anyway, he works better now, with some special oil.

the tone is maybe too perfect now ...
but i could go back with a problem i could nring back, that was nice for the speed variations of the tape, producing some nice tones. this is about the position of the cartridge : too high or too low.

the problem i have is from the electronic, don't know if you heard the difference between the echo position ( from my link ) , then switching to sound on sound : bvvvvvvvvvvvvvvvv bassy hum i don't like.

maybe some transistors to replace, or some bad ground somewhere, but only for the sos position.
then, a general hum i'd like to remove too.

[demonufo]

Can't load from your link for some reason. Just never loads up.

Just spotted your very first post with mention of Regis's page too!


I'm all out of ideas on the hum now. Wish I knew the deck better. Probably quite a lot different from the old copicat I had years ago.

[Xplorer]

i appreciate your help anyway, that's cool, thank you.
i've bought a tech book with notes about the echoplex machines from a tech, over 40 years ago. it might help me, for the electronic. i'll try some stuffs. carefully.

here it is, this link works : https://rcpt.yousendit.com/951815155/b9 ... 7f5345dbee" onclick="window.open(this.href);return false;

i'm done with free.fr for big files, yousendit works better.
you can hear the volume from 3 to 9, and the swtching to sos and BVVVVVV ; )
now the tone is too perfect, i'll put the cartridge back in a bad way, touching the tape a little, under the cartridge, to have those shimering pitch variations you can hear into this sample sometimes.

please let me know what you think.

[demonufo]

Actually I think it sounds great. It seems to clip a little in places though (in addition to the guitars distortion) so you may have set the record levels a little high, or the tape isn't biasing too well, or there are other factors involved.

In contrast to you, I prefer the perfect sounds without the pitch variations.

Actually I did have another thought about the hum. It could even be a ground loop, where you have too many earths, or certain earth points that either require earthing elsewhere, or lifting altogether. This is something you'll have to research with somebody more familiar though, I certainly don't suggest lifting earthed points at random.
How does it hum with the signal earth lifted?

[Xplorer]

thanks to have heard this sample. it helps me.

well, the record level is set at max, it's true, but it was the best to my ears, allowing not to turn the volume to high, cause when you turn up the volume too much, there's too much his, an too much buzz on the sos channel.

yeah, about the earth, i lso think that it could be the problem, but i really don't know how to do, and what do you mean by : lift the ground, or "lifting earthed points at random.
How does it hum with the signal earth lifted?"

? i'd like to do what you suggest but i don't understand what it means, from the english language, wich is not my first language.
also, what's "to clip" please ? ; )

in the beginning of the sample, you can hear the hiss and then the hiss and the buzz from the sos channe, then i play some eletric ladyland, it has some echo, but it's froma virtual tape echo into cubase. this electric ladyland is recorded at the same time by the echoplex on the sound on sound channel, and you can hear it played back later. after that, i use the echo position for some other things, and there you can hear what the echo looks like.

the echoplex tech book talks about changing some transistors too, the mps8098 with some t1598. this could perhaps help also, i'll see that later, after the earth problems, if it's still not good enough. the earth problem makes sens. but i really don't know from where to start, what i'm supposed to analyse. i don't have money to pay a specialist too, for a look at that.

for the pitch variations i can understand. those i'm talking about are the trebly smooth tones you can get, a good example at 2:09 in my sample. or 2:34.
i think that you are a specialist of tape recording, and i can understand that you prefer a perfect tone. for me this one is more like an effect.
but i'd like a tape recorder too, i'd like a Revox PR99 MKII ...
the tape recording has a big influence, to my ears, on the Hendrix Strat tone. i love it, it's a perfect combination.

[Xplorer]

here it is, compared to the previous sample. Now the tape doesn't meet the back of the cartridge when running, so there are less tape variations. no hiss very noticeable into this sample, but it's still the same as before, for when you turn the volume up. and the sos channel still has this kind of earth problem.

https://rcpt.yousendit.com/952290533/7f ... 7b00e0ab60" onclick="window.open(this.href);return false;

[clinchfx]

Hi Adrien,

I'm posting in reply to your PM.

It's very difficult to diagnose your problem with buzz, because it may be a grounding problem in your Echoplex or anywhere in your signal chain.

As for the hiss, this is a normal part of tape technology but it can become worse than normal as a result of worn heads. Other possible causes could be that the bias oscillator frequency has drifted, reducing the recording efficiency. This may be caused by resistors or capacitors that have drifted in value as they age. As I recall, there is at least one bias trap in the circuit, and this may be in need of adjustment.

While it is possible that blindly changing components may help, it is likely that the unit will need adjustments that require the use of test equipment, as well as in depth knowledge of tape recording and playback systems.

I'm sorry that I don't have an instant answer to your problems.

Peter.

[Xplorer]

thanks a lot for your reply Peter.

i've changed the caps, and even without tape running, it's the same hiss and buzz on the sos channel.
i don't know if the preamp works for both channels ( i guess so ) , then, the buzz would come from some another board ? because if it doesn't buzz on the echo channel, it shouldn't buzz too on the sos channel, at the level of the preamp...
by the way, do you recognize the preamp board ? i'm not totaly sure of wich one it is.
I'm working on a plan to build some boards, clones, of the ep3 with tubes ... it seems to be a more simple circuit. it could be an option.


Thanks,
Adrien

[Tazin]

Regarding the gray wire with the shielding. The gray wires shielding should be connected where the white wire is at the circuit board side ( just like you outlined with red dots in the picture). The other end of the gray wire with the shielding (where it attaches to the Sound on Sound switch) does not get grounded. Also, the Echo Sustain potentiometer is 500k linear.

[Tazin]

I also noticed that someone messed around with the wiring for the Echo OFF foot switch jack.....Why is there a 47k resistor in line with the jack wiring?? The green wire from the Echo OFF jack should connect to the lug on the Echo Sustain pot where the other green wire is.

[Xplorer]

Thanks,
well, since, i've reconnected the shield. The sustain pot is new, and yes i guess mine is lin. got it from tony at orbit electronic, who repairs echoplexs.

Regarding the echo switch ... i didn't noticed it, thanks for what you've discovered. i'm gonna watch this, and reply soon.

Adrien

[rgorke]

I think it sounds great. I would love it if we could have a sticky or something with Echoplex information on it. I believe qhite a few folks on here have Echoplexes and would appreciate and use information gathered.

[Xplorer]

Thanks, you liked how it sounds ?
Well yes, the echoplex and the other tape echos should have a separate section i guess , they are another world among all effects.
i'm planning to make some copys of the original boards, and simply do like George with the amps. so one could replace the damaged boards with some new ones, with the same components, without the need to discover where is the problem exactly, on the original boards.

And i'll also make a copy of a tube ep3. then,i'll have two options into my ep3 : solide state, or tubes, with some switchs.
in the end, i'll add a mod to modify the speed , manualy if possible, to allow a tape flanger. All that in my ep3. and the original board wouldn't be damaged as i would simply replace them. brown phoenolic boards, same components, some plugs for the transistors to allow to swap them easyly, and some kind of pins you know, just like the plexis boards, to make the components easy to change from the top.

this could be my project.