Those echoplex preamp pedals, which u like??

[harddriver]

Curiosity got the better of me, I ordered all the parts from Valvestorm hopefully he still has all that stuff in stock, all the paypal buttons worked. I love my Clinch EP-PRE but I want another project to keep me busy since my car accident in January.

[jnew]

You could build the other spec for comparison. That's my next project too.

[harddriver]

What spec is that the later brighter models of EP-3? Wasn't Eds echoplex like in the 23000 serial number?

You can't get to the order list from Valvestorms site, only via the link he provided so hopefully he still has the stuff. It let my order go through.

[jnew]

I don't know which spec Ed's used but if memory recalls, I believe the earlier spec was the brighter as it has a .022 and 220pF at the input and a bypass cap at the 3.3K leg of the JFET, to ground. The later spec has .047 and 100pF at the input and no bypass around the 3.3K resistor. This would yield more thickening tone. I've always used this but want to try the other one. I think the EP-Pre uses the first one I described.

[harddriver]

Great info there Mr. Newlyn! I appreciate it.

The echoplex schematic that you posted using the .047 cap and the 100pf cap at the input was supposedly used in EP-3 echoplex's serial number 12961 to 28591.

I distinctly remember someone saying and you can see from pics from VH1 in Japan Ed was using the EP-3's that had the chrome bezel around the smaller red power lamp. Supposedly Ed's were in the 23000 range but don't quote me.

My echoplex that I have just has the full red pastic power lens with no chrome bezel serial number 11666 so it is an earlier one but seems to darken the tone a bit more that my EP-PREs but I wouldn't call it mushy at all as Ralle described his project pedal. I've been real happy with my EP-PRE so if he used the brighter schematic the darker might be even more to my liking.

Sorry Stan! I'm not trying to derail your thead, That Badgerplex EP pedal with the 110V power cord interested me since the echoplex runs on 110ACV I thought that pedal might work for you instead of an 18DCV charge pump in the EP-PRE pedal. That might change the tone who knows?

[jnew]

Yep. For whatever reason, I've always thought Ed's probably used the .047 and 100pF arrangement. The compressor board was another hot topic and whether or not Ed's had that. I built one and finally got it working but never really knew where or how to incorporate it into the pre amp circuit. There was a lot of speculation on that as well. So I'm thinking of using the dual stomp box arrangement that I built for the two different spec pre's and leaving the compressor out all together.

[harddriver]

I just dug out my Factory Echoplex Owners manual that has all the models listed EP1 thru EP-3. I dug out the schematic for serial numbers 9451 to 12960 and the schematic is the same as 12961 to 28591 using the .047 and 100pf cap on the input everything else was the same same too exactly like the later serial numbers minus maybe some other minimal changes somewhere else in the unit.

At serial 9067 was the last of the EP-2 units. Starting at serial numbers 9068 to 9450 was the first EP-3 units and they have a different spec on the input side it uses a 100K resistor, a 220pf cap to ground then .02uf coupling cap, then 1Meg to ground, and a .022uf cap on the 3.3K resistor.

So that is cool to know mine is pretty much exact to the later EP-3's. Yes I do agree my EP-3 echoplex is a little thicker sounding than my EP-PRE but I'm not sure what serial numbered units he based his pedal on. I think Mr Clinch could remedy that or I might be able to change out those parts myself to the later specs.

So hopefully I'll get my kit from Valvestorm and start putting it together and I'll compare it to my echoplex and the EP-PRE.WOO HOO!

[harddriver]

Hey Stan to get your thread a little back on topic.

I spoke with Peter Clinch the other day and he did confirm that he used the brighter version of the earlier EP-3's and used the .022uf cap on the 3.3K resistor in consideration of the early EP-PRE design.

His new line of EP-PRE's now has an internal switch that allows you to switch the .022uf cap into or out of the circuit as you wish. With it switched out it will be darker and thicker like the later serial number EP-3's I listed above. You might want to give a newer EP a whirl I'm not sure which one you had when you tried it.

I'm looking to remove that cap on my EP-PRE and see how it compares to my EP-3 which is of the darker sounding ones.

[jnew]

There are other values to change if you are wanting to stay authentic to the later spec's. I'm sure you know this. Just saying.

[Haze13]

With this circuit you can see how different caps (dielectrics) can effect the tone. 40 years ago people were using what they had back then. Technology moves on, and you can make this preamp to sound!!! I've been working on BOSS ce-2 chorus for a while now, and with this type of a circuit I was choosing the caps and transistors (Jfet, BJT like 2240, bc549) for signal path, and the result is outstanding!!! Actualy I took another version of this common-source amplifier, it was Nelson Pass version and Jfet is a SK170GR. This is one of the best Jfets and is very famous in Hi-Fi audio.
I was compearing caps in the IN position and in the OUT. I used Polyester Metalised (Grey Rifa, Brown Panasonic, Philips, Wima MKS, Vishay Dale rodenstein ERO - Boxed cheap caps to cut short), polypropylene film and foil (Wima FKP2 - audio grade cap), Polyrpopylene Metalised (Orange drop p716, Wima MKP, Vishay dale rodenstein ERO 1837). Each one of them of the same value, tolerances - 2.5%-5%.
Wima FKP2 is the winner, I liked it the most! Then Polypropylene Metalised. Some times polple willl bypass large values like 10uf with 0.1% of the value of the cap. 0.1uf for 10uf cap for example. For a bypass cap go with Polyester.
Polypropelyne Film and Foil are big sized caps and they come only 0.033uf max from Wima. Metalised Polypropylene caps are smaller in size then Film and Foil and they come up to 4.7uf. There are others brans with larger values but they are much more expensive.
In the end chorus sounds much more clear, beautiful and musical! For Audio - use audio grade components, the result will be much better.

[jnew]

With this circuit you can see how different caps (dielectrics) can effect the tone. 40 years ago people were using what they had back then. Technology moves on, and you can make this preamp to sound!!! I've been working on BOSS ce-2 chorus for a while now, and with this type of a circuit I was choosing the caps and transistors (Jfet, BJT like 2240, bc549) for signal path, and the result is outstanding!!! Actualy I took another version of this common-source amplifier, it was Nelson Pass version and Jfet is a SK170GR. This is one of the best Jfets and is very famous in Hi-Fi audio.
I was compearing caps in the IN position and in the OUT. I used Polyester Metalised (Grey Rifa, Brown Panasonic, Philips, Wima MKS, Vishay Dale rodenstein ERO - Boxed cheap caps to cut short), polypropylene film and foil (Wima FKP2 - audio grade cap), Polyrpopylene Metalised (Orange drop p716, Wima MKP, Vishay dale rodenstein ERO 1837). Each one of them of the same value, tolerances - 2.5%-5%.
Wima FKP2 is the winner, I liked it the most! Then Polypropylene Metalised. Some times polple willl bypass large values like 10uf with 0.1% of the value of the cap. 0.1uf for 10uf cap for example. For a bypass cap go with Polyester.
Polypropelyne Film and Foil are big sized caps and they come only 0.033uf max from Wima. Metalised Polypropylene caps are smaller in size then Film and Foil and they come up to 4.7uf. There are others brans with larger values but they are much more expensive.
In the end chorus sounds much more clear, beautiful and musical! For Audio - use audio grade components, the result will be much better.

Pretty in depth about your gizmo circuits there. Good on ya.

[harddriver]

There are other values to change if you are wanting to stay authentic to the later spec's. I'm sure you know this. Just saying.

Yeah I'm not sure if there are any other variances but I do have my echoplex to compare directly to it so well see. If it gets closer I'll be very happy.

[jnew]

Do you have the echo plex manual with all the schematics as well. I can send you PDF copy if you don't.

[harddriver]

Thanks for the offer on the manual I appreciate that ! I do have one with all the schematics, I picked it up when I bought my echoplex a few years back. Luckily the damn thing keeps working so far, I keep plugging it in every now and then to keep that caps charged when I decided to drag it out of the corner, even the fan still works.

I run the EP-PRE's into old Ibanez echomachines for my quick and easy echoplex setup on my pedal board. I have the Valvestorm pedal parts coming(should be a fun project) to as well to keep my self busy since my car accident I'll be around the house for awhile.

NOT really the way I wanted to make time for some electronic projects!!!

[jnew]

I hear ya but hey, you're being productive.