I just noticed on the schematic that the circuit doesn't have polarized 1uf caps but on the perfboard layout they are polarized. Does it matter which you use? http://www.runoffgroove.com/eatremolo.html
It will certainly work with electrolytics, I built mine with them. But I've heard it works better with poly caps.
Regards
RDV
Electrolythics worked for me and it sounds great!
I used tants- but thats all i had at the time and it sounds great--
I think I might have used electros..... Just measure which capacitor connection has the higher +V and that's the + side of your cap...should work fine
yeah, it won't work if you use electros backwards. actually i can't back that up with any science, but i got one backwards once and it didn't work until i figured out which way to put them.
looking at the schem here:
http://www.generalguitargadgets.com/v2/diagrams/eatrem2_sc.gif
C5 - +ve towards R9 & collector of Q3
C6 - +ve towards R10
C7 - +ve towards R11
HTH! btw, i used tants because the case i was using didn't have room for film or electros and to be honest, i think the non-linearities of the whole FET gain element thingy far outweigh any benefit to getting a 'purer' sine wave by using high quality film caps.
Quote from: idlefactionyeah, it won't work if you use electros backwards. actually i can't back that up with any science....
I saw a blurb in Radio-Electronics magazine long ago that said the first use of electrolytic caps was actually as rectifiers :shock:.
Take care,
-Peter
I would love to build this one... but it looks kinda complicated! :shock:
What are the component parts? (Q1, Q2...) And how do you connect them? Also, how would you connect the different pots to the board
I'm still a newbie- so prepare yourselves for a ton more questions coming up... :twisted:
Quote from: AxmanjrWhat are the component parts? (Q1, Q2...) And how do you connect them? Also, how would you connect the different pots to the board
Layout etc here:
http://www.runoffgroove.com/eatremolo.html
It's an easy build ;)
You should also check out RG's layout. I used this one and it works great...easy and fun.
http://www.geofex.com/PCB_layouts/Layouts/eantrem.pdf
Thanks Michael Allen for the link! By the way, what are the values for the pots (level, depth, speed)?
Also, if I were to hook-up an LED, where would I place it in the schematic? Would I need anything else for the LED (an extra resistor...)?
Thanks in advance!
heh welcome :)
you can find the ea trem and loads of other high quality projects at
http://www.generalguitargadgets.com/
HTH!
And Small Bear Tweak-O is a good pictorial of how to wire everything including pots.
The LED's you have to find the flat portion of the circle at the base of the lens...that corresponds to the schematic of the LED's flat 90* marking.
It took me a few times to get it...now I have two nice ones.
DIY FAQ has alot of good info and links you may find interesting.
When I look at this page http://www.generalguitargadgets.com/v2/diagrams/eatrem2_sc.gif, I notice that, for the VOLUME, DEPTH, and SPEED controls, it says 25k-A, 1M-B, and 25k-A (respectively). Also, does R12=VOLUME, R13=DEPTH and R14=SPEED? Are these the pot values?What does A and B stand for (my guess would be AUDIO and LINEAR :? )?
But then I look at this page http://www.runoffgroove.com/eatremolo.html, I see that the values are different (VOLUME=100k-A, DEPTH=250k-L, RATE=100k-RA). I'm assuming L=linear. But what is RA?
Of the two above links, which is more preferred? Also, could I switch the pot values around (ie use the runoffgroove.com pot values in the GGG.com schematic)?
Lots of questions, but I'm still at a lost...
Quote from: AxmanjrWhen I look at this page http://www.generalguitargadgets.com/v2/diagrams/eatrem2_sc.gif, I notice that, for the VOLUME, DEPTH, and SPEED controls, it says 25k-A, 1M-B, and 25k-A (respectively). Also, does R12=VOLUME, R13=DEPTH and R14=SPEED? Are these the pot values?What does A and B stand for (my guess would be AUDIO and LINEAR :? )?
But then I look at this page http://www.runoffgroove.com/eatremolo.html, I see that the values are different (VOLUME=100k-A, DEPTH=250k-L, RATE=100k-RA). I'm assuming L=linear. But what is RA?
Of the two above links, which is more preferred? Also, could I switch the pot values around (ie use the runoffgroove.com pot values in the GGG.com schematic)?
Lots of questions, but I'm still at a lost...
RA means 'reverse audio', a hard to find little bugger.
I used the Runoff Groove version, but both work, the GGG version doubles as a booster. No I don't think you can switch around the pot values.
Regards
RDV
I guess you could use a 500M RA pot from small bear.
If you can't get a reverse audio, then a linear is a better thing to have than an audio.
Would that be a 25k linear pot for SPEED?
Also, was I correct in saying that A=audio and B=linear?
Hi Axmanjr, maybe this article will make that clear, as well as other stuff about pots.
http://sound.westhost.com/pots.htm
Cool, thanks Kaiowas! I'll get to reading! :D
Glad to help!
I'm looking around, and I noticed that I can't seem to find a 25k audio pot anywhere! What a bummer! Are they still around? If not, then what other substitute values can I use for the pots?
Also I'm having trouble finding the caps in both those schematics. I can't find the right type (metal, film...).I can't find any caps in those values. Instead, I found weird values- like 47Mf.
Axmanjr,
I think the 25K audio pot is hard to find, very hard to find, in the article i told you earlier, you may read that you can change a linear pot to a log (audio) one, they tell you how to do it very clearly.
About the caps types, you can use any non-polarized type (ceramyc, film, etc) for the non-polarized caps in there (C8,C1,C2,C4,C5,C6,C7), and electrolytics for the other ones (C9,C3).
An about the caps values, i think the only value not-so-easy-to-find is the 0.05uF (C8), but anyway, if you don't find the right value of cap, you can put some caps in parallel to add them (i.e. to make the 0.05uF, you can put 2 of 0.022uF in parallel, C=C1+C2, C=0.022uF+0.022uF, C= 0.044uF, and 0.044uF is pretty close to 0.05uF).
You also can put them in series (C=(C1*C2)/(C1+C2)).
OH! i'm assuming you're using the "improved EA Tremolo" from JD.
Tell me if you don't understand something.
Bye!
Thanks again Kaiowas! I haven't read the part where the article explains about changing linear pots to audio pots- but I'm getting there :D !
In this diagram http://www.generalguitargadgets.com/v2/diagrams/eatrem2_sc.gif, what does sw1a, sw1b, and sw1c mean. I'm assuming that sw1 means the footswitch, but what are the 3 different numbers that are scattered throughout the schematic all about?
And also, since I'm still a beginner and don't want to trouble myself as much as I already am, is it possible to not include the DC Jack in the schem? If so, how would I do this? Would I simply just omit J3and have the (+) terminal of the battery connect to R15 and so on... and R18 would connect to it also? Please let me know if this is right.
Sw1a, b, and c refer to the poles of a 3PDT switch. You're right on the exclusion off the DC jack though.
Okay, here we go again! After reading the previous article on POTs, I noticed that you can change an audio/log pot into a reverse audio pot by using a resistor. However, there is nothing there about changing values of pots (say- like from a 50K to a 25K). There also isn't anything on how to change pots from log to linear (or vice versa). Is it possible to accomplish these things?
Also, as again, I CANNOT find the 25k audio pots anywhere! I went to kiesubs (an electronics store here in Vegas- who boasts about having everything!) and I couldn't find them there. So, is there any other possible pot values that I could use to replace the 25k logs (maybe 50k logs- or even 10k)? How will this affect the effect pedal if I could do it?
I'm using this schematic http://www.generalguitargadgets.com/v2/diagrams/eatrem2_sc.gif. Thanks for any help!
I'd say RA means Reverse Audio, or reverse log.
Use a regular log pot wired in reverse, or a linear, or... experiment and see which you like.
GGG has the original EA, Runoffgroove has a modded version. which is the preferred version? Dunno. For runoffgroove, it's the modded one (duh) but your mileage may vary. Tinker, and come up with your own ;)
Mucking about with values is right there at the heart of modding, which in itself is at the heart of improving *your* sound. You won't blow up anything by changing pot values or cap values, so knock yourself out. Keep a log of what you change, and what happens to the sound. Try to understand why...this is a very powerful learning experience, comparable in my mind to having lessons vs. playing in a band.
Enjoy.
*edit*: I forgot about a page 2. Sorry 'bout that ;)
It's easy to make a linear pot into whatever you want, but more or less pointless to mod a log one. Just use the log, if it seems to concentrate all of it's sweep in one corner, buy a linear pot.
Stick in a 50k and a 10 k and see which one you like best. where are you? Mouser, Farnell, my shop around the corner all carry 25k? Smallbear, too.
Thanks for the reply and motivation Mike! :D
I guess I should experiment. I was under the assumption that if I used different values in a schematic that I might mess something up. But since I'm breadboarding it first, then it should be no problem! I'm from Las Vegas, NV. I tried going about finding all of my components without the need of ordering, but I guess that may be needed- of course I'll still experiment with what I may have readily available here!
Okay, so I'll post back later (say a week) concering the progress of my pedal. Thanks!
Let us know if we can help you out when you get what you need!!
I used some 1uF films in mine. They are pretty small in physical size, too. Someone gave them to me a while ago, and I thought to myself "what the heck can I use these for?" Enter the EA tremolo...
I sure will Kaiowas!
Hey Paul, where in Vegas are you from? Where do you do all of your component shopping?
I built the runoffgroove one and I like it a lot. :D about the pot, you could use a tapering resistor to make a lin pot act like a reverse log pot ;)
"Hey Paul, where in Vegas are you from? Where do you do all of your component shopping?"
I live in the NW part of town, near Summerlin. Lake Mead and US95 area.
Getting components is kind of a pain in the neck. I used to go to Sandy's Electronics a lot, and they and Kiesub Electronics have merged now. I haven't been there since that's happened. Sandy's has closed and moved their stuff into the Kiesub store off of Highland Drive.
I go to RadioShack a lot of the time for little stuff, but I try to avoid it these days since it is such a rip-off to get parts from them anymore.
For tube stuff, I use tubesandmore.com, thetubestore.com, hoffmanamps.com and partsexpress.com
I have placed a few orders with Mouser.com, too.
I have also scored a few things off of ebay, like Ge transistors, 2N5089s and 2N5457s.
It really all depends on what I need and how fast I want it. I haven't had to buy too much stuff outside of my parts stock for a while. Someone who used to be an instructor at DeAnza college at one time had given me bunches of resistors, caps, diodes, LEDs, enclosures, IC chips, transistors, solder type terminal strips, transformers and all kinds of other stuff. That has kept me going for just about a year now! (He used to own the coffee shop a few doors down from where I worked and we became good aquaintances since we both liked electronics)
I'm up by Sunrise Mountain- next to the Nellis Base. So a daily trip to Kiesubs is not particularly on my schedule! I'm still a beginner... but I'm trying :D
Hello EA temolo-ites
Is it possible to get the depth part of the curcuit so deep that the volume is actually going on and off. I am using the runoffgroove version and the first 25% has no effect (so it can be used as a volume boost too) I am happy to loose that part.
Thanks!
Chris
Uhmmm... Mmm lemme think... Maybe losing the resistors on one side of the depth pot, but it might start popping at you...
Reduce significantly the value of the 180 Ohm resistor at the emmiter of the first transistor ant the depth will be increased. Not sure if it'll go where you want it to go :roll:
Quote from: Manolo DudesReduce significantly the value of the 180 Ohm ...
Oooops!.. sorry. Now I see it shall increase the speed, not depth :oops:
:mrgreen: That can be cool too you know. You could have a switch "Turbo" or something :D
axmanjr:
That's cool. I was wondering if anyone else in Las Vegas does this stuff. 8)
Yeah, it's kind of a pain getting to any other part of town from your area, isn't it? It's a long way before you can even get onto I-15. I am only one street light from getting on US95.
I used to have a few friends who lived in Hollywood and Lake Mead area. I also used to know a bunch of people stationed at Nellis AFB. But they have all moved away and stuff.
25k audio pots can be had for about $1.25 at WeberVST. I'm just about to start on an EA trem and after looking around, found that was the only place. it's only about $0.04 more than mouser's alpha pots, construction seems to be a bit flimsier, but it shouldnt matter. I'll probably build the thing this weekend..
Aaron
Cool Aaronkessman, let us know how it goes!
I had mentioned this in another EA Trem thread, but you can get 25K audio pots from //www.stewmac.com. They are expensive ($8.97 each :shock: ), large in size and come with a split shaft. I did bite the bullet and order them for my EA Trem and they work well. No problems so far.
What about these pots? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2598478181&category=4660
What are CTS pots anyways?