Author Topic: Echoplex Delay + Preamp shaping dry signl  (Read 1376 times)

claytushaywood

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Echoplex Delay + Preamp shaping dry signl
« on: October 05, 2017, 02:57:00 PM »
Im looking to build a simple 3 knob delay that sounds echoplex'ish along with the echoplex preamp circuit in front of it.  Are there any pcb's out there that accomplish both of these tasks?  Or a recommendation for a simple delay to combine with say a fatpants build?  I dont need modulation on the delay.

I read about the new dunlop echoplex pedal and even it admits that the echoplex preamp sound is only applied to the delay signal and for the full effect by their echoplex preamp pedal to play in front of their echoplex delay pedal.

Ive looked but im unsure the easiest way to complete this task?  Also- wouldnt running a fatpants before a pt2399 delay cause it to clip and distort out?

Boba7

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #1 on: October 05, 2017, 04:06:07 PM »
I've had good results with a 1776 Multiplex Jr going into a Fatpants Jr (now replaced with a more exact Echoplex preamp, based on Aion's schematics)
I always run pt2399 delays before Echoplex preamps as they lack headroom.

midwayfair

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #2 on: October 05, 2017, 04:23:02 PM »
You can modify the hamlet very slightly to use a FET input device instead of the BJT. If you rework the output slightly to include some separation resistors and a larger volume pot, it'll be even closer. You'll get tails bypass like the original and the preamp all the time. This was sort of the point of the Hamlet's setup even though I didn't want to mess around with trying to pretend that the pt2399 in it can remotely sound like well maintained tape.

You might need to let a little more bass into the delay line. I think the Multiplex's delay line values offer an alternative set.
Myself's music & things I make: http://jonpattonmusic.com. My band: http://midwayfair.org. PCBs of my designs from: http://www.1776Effects.com (Bearhug Comp & Cardinal Harmonic Trem); http://www.jmkpcbs.com (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: www.madbeanpedals.com

JC103

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #3 on: October 05, 2017, 06:40:28 PM »
Fatpants into an old Boss DD-2 will get you close. You could even try a Fatpants into a blender loop with a transformer in front of the DD-2 (with a dummy jack) so that you get 100% wet back into the blender. I used a Radial ABY box w/xfmr and it sounded great like this. Mind you this was in the studio... it's a little elaborate for the stage.

claytushaywood

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #4 on: October 05, 2017, 11:06:19 PM »
Thanks for the replies- I really dont need or even want the modulation from the multiplex jr- the deep blue delay is almost exactly the same as the multiplex jr without modulation- 3 caps seems like theyd be the bulk of the difference.  the deep blue was originally advertised as "loving"distortion. 

what do you mean by dummy box and why the need for a transformer blend loop?  I was thinking just some regular delay- but i really cant think of any that are bright enough for echoplex sounds- i was even thinking the ibanez de7- its got a brighter setting on it. 

and jon i wish i knew more to understand how to modify the hamlet to sound more echoplexy... but... i dont :(  I just listened to the hamlet delay demo and I am definitely thinking thats the best sounding pt2399 ive ever heard. 

Id like to modify the hamlet- but the fatpants is a simple enough circuit to build them both- maybe the hamlet could handle some boost with that LED to ground mod on the pt2399?

is the aion echoplex that much different sounding than the fatpants?

looks like dunlop just came out with 2 seperate pedals- the echoplex delay and the echoplex preamp pedal- theyre acting like the original echoplexes didnt have much volume on tap- maybe so people dont distort the crap out of their "variable headroom technology" 20v echoplex delay pedal? 

The combo sounds pretty good from what ive heard though!

Thanks for all the input!

Boba7

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #5 on: October 06, 2017, 04:03:22 AM »
I think if you could get one of those Ibanez digital delay (EM5, DL something, I can't remember the name exactly), they're pretty good and cheap used, and they're bright but with a bit more "character" and warmth than the Boss delays. That and a Fatpants and you're good to go!

I've never built the Hamlet delay, but I sure will someday.

Aion's echoplex is better than the Fatpants in my opinion, but the difference is quite subtle. I've spent literally hours comparing the two and finally sold (for cheap) the Fatpants to a musician friend. But I'd recommend the two circuits with no problem. My only advice would be to try different caps in place of the 22n or 47uf that both Aion and Madbean include. And read Aion's build doc. The Idss and Vp values actually do make a difference, though I really really can't explain how! :)

Anyways, regardings the caps, the off position on Aion's circuit (no cap) is my favorite, and it is darker. Then I put a 10n and 22n on both sides of the switch as I don't need the gain/volume the 47uf provides. I find 22n is brighter and 10n is the perfect in between for my taste. Again, a subtle difference, but I like it.

midwayfair

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #6 on: October 06, 2017, 01:43:30 PM »
and jon i wish i knew more to understand how to modify the hamlet to sound more echoplexy... but... i dont

I'll help :)

The Fatpants can't quite do what needs to be done: The Hamlet uses a single transistor as a phase inverter. I forgot last night that Brian's new version of the cave dweller pulls the same stunt and already contains the FET for the audio path. The Hamlet just has some extra room for tone shaping and more headroom in the dry path, which won't matter much after converting to a FET audio stage. Brian's included the Hamlet's LED, so the delay path is safe, too.

If you want to modify the Hamlet, the input stage uses a BJT with a single biasing 4.7M resistor from the base to +18V for the dry signal. All that needs to be done is to connect the resistor to a ground point instead of +18V. This will help to properly bias a FET.

Now, you COULD simply put a DGS FET in there right away -- the 2N3819 is a good choice, because it has a lot of headroom and is pretty easy to find -- with the knowledge that the absolute idea modification would be ensuring that the source (which connects to the delay line) is as close as you can get to 2.5V, which is about where the BJT version lands. This can help prevent some popping. If you do get pops, there are other ways of handling the bypass.

That sort of modification doesn't involve anything traumatic for the PCB. There are some people who think that the high output impedance of the echoplex is part of the sound. For that, I would simply use a 100K or 500K for the volume trimmer, and then put a resistor, maybe 100K, between the board output and the bypass. You'll lose some signal, and it might be less useful as a preamp (in particular, it won't be that great into a recording console anymore), but the high output impedance can affect the treble content in a tube amp. Plus the modification is really easy to reverse -- you'd just short the resistor. You can even use an aligator clip to see if it makes a damn bit of difference (that's a technical measurement).

I released the basic Hamlet on Osh Park recently, so it's possible to get boards again without etching if you decide to give it a shot.
Myself's music & things I make: http://jonpattonmusic.com. My band: http://midwayfair.org. PCBs of my designs from: http://www.1776Effects.com (Bearhug Comp & Cardinal Harmonic Trem); http://www.jmkpcbs.com (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: www.madbeanpedals.com

claytushaywood

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #7 on: October 07, 2017, 01:38:48 AM »
and jon i wish i knew more to understand how to modify the hamlet to sound more echoplexy... but... i dont

I'll help :)

The Fatpants can't quite do what needs to be done: The Hamlet uses a single transistor as a phase inverter. I forgot last night that Brian's new version of the cave dweller pulls the same stunt and already contains the FET for the audio path. The Hamlet just has some extra room for tone shaping and more headroom in the dry path, which won't matter much after converting to a FET audio stage. Brian's included the Hamlet's LED, so the delay path is safe, too.

If you want to modify the Hamlet, the input stage uses a BJT with a single biasing 4.7M resistor from the base to +18V for the dry signal. All that needs to be done is to connect the resistor to a ground point instead of +18V. This will help to properly bias a FET.

Now, you COULD simply put a DGS FET in there right away -- the 2N3819 is a good choice, because it has a lot of headroom and is pretty easy to find -- with the knowledge that the absolute idea modification would be ensuring that the source (which connects to the delay line) is as close as you can get to 2.5V, which is about where the BJT version lands. This can help prevent some popping. If you do get pops, there are other ways of handling the bypass.

That sort of modification doesn't involve anything traumatic for the PCB. There are some people who think that the high output impedance of the echoplex is part of the sound. For that, I would simply use a 100K or 500K for the volume trimmer, and then put a resistor, maybe 100K, between the board output and the bypass. You'll lose some signal, and it might be less useful as a preamp (in particular, it won't be that great into a recording console anymore), but the high output impedance can affect the treble content in a tube amp. Plus the modification is really easy to reverse -- you'd just short the resistor. You can even use an aligator clip to see if it makes a damn bit of difference (that's a technical measurement).

I released the basic Hamlet on Osh Park recently, so it's possible to get boards again without etching if you decide to give it a shot.

what do you mean the fatpants cant do what needs to be done- i was just thinking about using the fatpants and a delay to try to get a echoplex'ish sound.

are those few mods really going to give me an echoplex sounding preamp?  is there anything else that could be done to get me closer to the echoplex preamp sound or the delay filtering?

thanks a bunch!  im excited!

claytushaywood

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #8 on: October 11, 2017, 02:30:22 PM »
Also- I'm not seeing the build docs for the oshpark board im bout to purchase.  thanks midwayfair!

JC103

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Re: Echoplex Delay + Preamp shaping dry signl
« Reply #9 on: October 11, 2017, 09:39:31 PM »
I've also heard those old Ibanez digital delays are pretty cool and full of character. I suggested the DD2 or a MIJ DD3 "long chip" version because they sound better than the non made in Japan DD3's. If you run a Fatpants (I have the 2013 version, not the jr.) into a blender and place a DD2/3 in the loop you need to insert a dummy cable in the second output jack of the DD2/3 so that the main output jack only outputs the delay/echo signal. It's a simple dry kill trick. I've also placed a 1:1 transformer (Radial ABY box purchased second hand) in the loop before the DD-2/3 to mimic the job of a tape head. You get a little darker/fatter delay tone with some compression–much like what happens when you are actually hitting tape in an Echoplex. My friend has a well maintained Echoplex EP-3 and this is the closest sound that I've gotten to his old one by faking it.
« Last Edit: October 11, 2017, 09:42:34 PM by JC103 »