echo

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Re: echo

Postby Smallbox » Sun Jul 05, 2009 4:23 pm

David B wrote:
"BTW my friends EP3 would be running in normal echo mode then switch to sound on sound all by itself.Q7& Q8 voltage dropped in half from 25 to about 12 volts when this happened.... cause,one of the .01 caps in that circuit was faulty..."


Good info to add to the "EP Service Notes",...Or is that already there? ( I haven't checked mine... :roll: )
Anyway, thus far you're turning into the, I mean THE EP expert service-man, the go-to guy for EP's on Marstran forum :wink: :!:
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Re: echo

Postby David B » Mon Jul 06, 2009 2:07 pm

Who me , nah still learning how these things work but learning more :) to answer your question this particular failure isn’t mentioned in the repair notes. I’ll have to read thorough them again, IIRC there was mention of the same symptoms but caused by a faulty switching jack..
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Re: echo

Postby Smallbox » Tue Jul 28, 2009 10:31 pm

Hey DB---you're still the resident EP expert here on the forum, sorry! ... by virtue of most responses/experience :wink: :!:

On the subject of the Heads used in these units, I found a pertinent link.
It seems another company, specializing in recording heads, has sold their remaining supply
of heads to JRF Magnetics, mentioned earlier in this topic.
So, if you were needing heads to replace those in your Echoplex, maybe it's a good time to contact
JRF Magnetics (see earlier posts in this topic, and/or link below for contact info).
And, here's the link where I found that info:
http://www.magneticheadcompany.com/
HTH!
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Re: echo

Postby David B » Sat Aug 01, 2009 12:06 am

Well responses yeah :lol: had to pick some brains to point me in the right direction 8) I also set the bias per the manual and man that fan sucks the dirt in, what a mess so a lot of cleaning! whew... Belt looked OK thought motor was askew so that had to be adjusted . Filter caps the owner wanted to keep the originals.

Good find on JRF Magnetics for replacement heads :wink:
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Re: echo

Postby Smallbox » Sat Aug 01, 2009 8:51 am

HI David,
Finding out about those Nortronics heads being sold to JRF was pure luck. Found the info by accident while reading.
I think these types of parts for "vintage" tape machines (like the EP's) are similar to
the "vintage" or "nos" valve supplies===they are limited===a finite resource!
Glad to see that someone recognizes an opportunity and also has a genuine interest, as well as the thorough understanding
of the science behind Magnetics as it relates to tape machines.
I find it a bit frustrating "keeping up" these days, due to the rapid pace of more modern (digital) technology in our Computer Age.

That's what's cool about the people who are interested in AND pursue the repair, development AND/or manufacture of
"new but vintage" Technology. Recent examples: the new valves being produced in the UK (a recent topic here at Marstran),
also machines like the Fulltone Tape Echo (how are they really? never heard or used one...).... and certainly
ALL who are "into" our amps , efx, etc. And I mean really(truly) deep "into"....I think DEVOTED is a good term for it.

I think a GREAT example is BKW and the Transformers
he studies/documents/rebuilds/ develops etc etc---it all becomes a labour of love that comes from interest in the old methods
and how to keep them around since "modern technology" has rendered them "obsolete" (speaking of obsolete,remember Joe Pampel?)....
Anyway....
Back to the heads!
Have intentions of at least inquiring with JRF about exact heads in stock/prices. Will report back here....

Have a nice one,
Ray
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Re: echo

Postby David B » Sun Aug 02, 2009 4:10 pm

Hi Ray,

Sure does seem that most things manufactured today are done cheaply with built in obsolescence for maximum profit, it’s become a throwaway society.
Thankfully for us we have Brian to provide us with new old technology and hopefully the TechTube people will continue to forge ahead refining their E813CC . Haven’t heard the Fulltone Tape Echo either but I would think it would be a bit quieter than the ol EP3’s we love.

Do let me know the outcome of your inquiry, might be wise idea to have extras in the bucket.

Speaking of Brian’s iron I have a friends 45 built in 2004 (porting a 103 OT) in for a checkup, man I forgot how good this those 103’s sound ! Really nice tone and I couldn’t resist the temptation to try my newly built fuzz through it, big fun :D :D :D
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Re: echo

Postby David B » Sat Oct 30, 2010 1:22 pm

Finally got around to changing the lytics, though not a big change there is a noticeable reduction in hum and noise 8)



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Re: echo

Postby dai h. » Sun Oct 31, 2010 3:30 am

good job! :mrgreen:
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Re: echo

Postby David B » Sun Nov 07, 2010 1:31 pm

Thanks Dai,

The Spragues seem to be behaving themselves, no issues :D
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Re: echo

Postby dai h. » Fri Nov 19, 2010 9:54 am

hey David, have you ever checked out the datasheet for Rifa axials?

was looking at some "PEG124", and the life given is insanely long--27,500 hours at 105deg.C. :shock:

http://www.kemet.com/kemet/web/homepage ... PEG124.pdf

also I was reforming some caps recently and decided to form some others for the heck of it, and it was interesting since a Rifa 220uF25V (don't remember the series, but I think it was marked "long life") showed low leakage compared to some other ones (that were around the same cap. value)--that is measuring the voltage drop across a series 100k R. The PEG look ideal for the first one after the rectifier(or maybe that plus the one after also).
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Re: echo

Postby David B » Sun Nov 21, 2010 12:56 pm

Hi Dai,

I did not as those caps aren't readily available stateside but wished they were, do they have can caps? would be nice for an old Pioneer receiver I want to fix up.

David
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Re: echo

Postby dai h. » Sun Nov 21, 2010 7:01 pm

David,

I'm not very informed about their range but I vaguely recall seeing Rifa in radial packages, maybe in a catalog or datasheet(?). The ones I was looking at were at one place here I buy from occasionally and they only have a few values avail. 22,47uF450V and a couple smaller ones useful for cathode bypass(100-470uF25V?). There are other common al.electros avail. here which are long life 5,6,8000 hrs. etc.) but AFAIK no axials. Seem mostly for modern power supplies, PC mobos, and some higher voltage (400V-ish) "lighting ballast" caps(something like that). There are some newer ones that look kind of interesting, apparently intended for automobile use with high temp. ratings. Assuming there isn't any reason not to use them, appear they might be ideal for something like power tube cathode bypass (since the cathode R gets hot). With the long life caps, the low maintainance aspect is pretty appealing since it can be a pain replacing them. On this PC monitor I'm looking at now, I tried to choose long life caps for replacement and so far (been a while but forget exactly when I did it) seems to be working trouble free. Oh, and I remember reading something interesting where this guy (who has a great DIY mostly audio-oriented page) stated how he didn't like to build cathode biased amps due to the aspect of internal heat contributing to shortening of life for components. I don't know if I personally would totally avoid (power tube) cathode bias, but the focus on the heat aspect was interesting (lifetime, stability). Might have been some proper engineering term like "thermal engineering"(?) if memory serves.
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Re: echo

Postby David B » Sun Nov 28, 2010 11:46 am

Dai,

Don't see anything above 200vdc, is there another series with higher voltage ratings?

No 6800uf either, that is what I need to recap the Pioneer, thinkin Chem-Con might have em

http://www.chemi-con.co.jp/e/catalog/aluminum.html
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Re: echo

Postby dai h. » Tue Nov 30, 2010 1:34 am

David B wrote:Dai,

Don't see anything above 200vdc, is there another series with higher voltage ratings?


do you mean in regards to the RIFA? (Sorry), maybe there is, but I don't have much familiarity with their (however many there are) series.

No 6800uf either, that is what I need to recap the Pioneer, thinkin Chem-Con might have em

http://www.chemi-con.co.jp/e/catalog/aluminum.html


It probably depends on the voltage, but 6800uF sounds like a value that shoudn't be too hard to find. Generally al. electros have gotten smaller (so could be somwhat ill fitting if recapping old equip. w/new stuff) and seems higher voltage caps have less selection and axials do seem much less avail.

Also, from what I've been reading, it might be a good idea to stock up (or keep a good eye out for deals) on some semiconductors such as "full size"("through-hole"?) transistors (2SC1815, 2SK170 apparently going to be discontinued). (Maybe this won't be as much of a problem in the U.S.?) but it's looking like more stuff is going to be made in surface mount only. So not a complete halt for DIY(I assume there are or will be surface mount equivalents), but the size can make things more physically difficult (though SMT has obvious advantages as well).
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Re: echo

Postby David B » Tue Nov 30, 2010 9:47 pm

Yup was wondering if Rifa had that range but think I found a source for the 6800uf over at AudioKarma
Surface mount! yuck ! haha. Yeah this miniaturization thing is catching on darn it, good idea stocking up on the old stuff.

Back to Echo-Plex stuff this is cool for those who want to maintain their machines but were afriad to ask..

[youtube]http://www.youtube.com/watch?v=qWpj85HN7H4[/youtube]
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