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Geek 20th February 2008 08:18 PM

EDCOR Releases Line of Guitar OPT's
Some low power ones to start...



It's a beautiful day! :)

Have you been lurking at their forums, George?


Fuling 20th February 2008 08:56 PM

Those 1700 ohms units are quite interesting as they might be a good match for some low rp tubes (triode wired sweep tubes like PL504).
Using the 16R versions with 8R speakers would get us down to 850R on the primary, certainly interesting for low power cathode follower amps!

ErikdeBest 20th February 2008 09:26 PM

Hi Fuling

I saw in another thread that you already used Edcor's in some other projects and now you are looking at them again! Sure I understand, as the performance/price seems to good to be true! Besides leaving some drool on the Edcor's, I am also drooling on the One electron chokes intended for parafeed circuits...

But, on a practical matter, may I ask how you buy the transformers? Do you order them directly from the USA, or do you buy them through Edcor Europe? I once requested the prices from Edcor Europe, but they were about twice the USA price, still not that expensive, but it seems it can be cheaper.

And to the US based members. How much tax etc should one add to a purchase within the USA? I have an uncle living in Colorado and plan to visit him, and I could ask Edcor to deliver a package to his place before I go back to the Netherlands.

Many thanks, Erik

mashaffer 20th February 2008 09:33 PM

The interesting thing is that the guitar versions of the single ended open frame OTs claims a better freq resp than the general use versions for the same price (40Hz v.s. 70Hz). Makes one wonder whether they might be a better choice for hi-fi use as well.


Boris_The_Blade 20th February 2008 09:52 PM


Originally posted by ErikdeBest
And to the US based members. How much tax etc should one add to a purchase within the USA? I have an uncle living in Colorado and plan to visit him, and I could ask Edcor to deliver a package to his place before I go back to the Netherlands.
No tax unless you are in the same state as Edcor, or Edcor has operations in your state (not likely in Colorado).

so, only factor in extra for shipping:up:

Fuling 20th February 2008 10:18 PM

ErikdeBest: Iīve never purchased anything from Edcor personally, the two sets of transformers that Iīve bought this far has been from two different group buys here in Sweden.
I didnīt arrange any of those group buys, perhaps Ryssen and Soundbrigade (both members of this forum) can give you a better answer.

mashaffer: I noticed the differences between the specs too.
Just like the small Hammond 125-series transformers the old Edcors performs better than what the specs says, maybe they have just updated the numbers in the datasheets.
Making guitar amp transformers with better LF performance than their hifi units seems a bit odd.

chrish 20th February 2008 11:47 PM

If you look at the spec you will notice that the SE 10 Watt Guitar amp is the same size (and price) as the SE 15 watt hifi transformer, same with the 15 Watt Guitar and 25 Watt hifi. Similar thing for the PP transformers.

So perhaps the guitar transformers are more conservatively specced for power, but since they are bigger will have better low freq response? Just a guess...

If this is so, it looks like a whole bunch of options available for the hi fi application, as previously the 25 Watt open framed output transformer was only available in 7.6K load. Now the 15 Watt guitar transformer (same size and price as the hi fi 25 Watt unit) has 1.7K, 2.5K, 5K, 8K and 10K.

Something else I just noticed, could not find the enclosed output transformers any more. Have they stopped selling them?


Edit... Could not get a link to the enclosed transformers, but I made a guess as to the URL and had success:

Geek 21st February 2008 12:32 AM

Hi all,

I know the guitar transformers are designed to take more abuse, so naturally they are going to be slightly heavier than the XSE and XPP. They are also OK for bass guitar.

The impedances are chosen to be super useful. Example is 6.6K is a great sweetspot for 6V6 (little less power than 8K, but a lot smoother OD point). Just buy the 5K:6R and hook 8 ohms to it. Same with the 2.5K:6R to make 3.4K with 8 ohms.

I've yet to meet an Edcor I didn't like. Brian over there seems to know what he's doing :)

I'll let you know when I get a pair to beta test.


kevinkr 21st February 2008 01:05 AM

I'm a little concerned about these new edcor guitar amplifier transformers, to be good for guitar use they really ought to be a lot crappier than typical hifi transformers, and from what you guys are saying they sound like they were far too conservatively designed - while you don't want them to blow up on you, you do want lots of leakage inductance, undersized relatively easily saturated cores, made with low quality iron, and poor performance at the frequency extremes. They really aren't supposed to be all that linear. So if these are good for hifi they ain't going to be all that good for a guitar amplifier... And as a corollary if they are good for guitar use they won't be all that good for hifi.. :xeye:

If anything they should be lighter than a hifi transformer of comparable power rating, otherwise indicates they were designed by people unfamiliar with the special needs of guitar output transformer design. (Core too large for the power rating, and it's an art today, fortuitously the original fender transformers were the cheapest trash they could find.) Incidentally I have had direct experience of this phenomena with a vendor I shall not name, great hifi transformers, guitar PP transformers with linearity too good for the task. (They sounded lousy)

Umm, I guess the other clue is the UL tap, almost never used in guitar amplifiers.. I think there are one or two oddballs that do use UL but is rare. (And of course I can't remember which, and they are mostly recent designs) No classic Fender, Marshall or Vox design I can think of uses anything other than pentode connection.

These are probably very good transformers, but I just wonder if they are a bit too good for the intended application.

I hope someone will try one in a guitar amplifier soon and answer this question.

Hey George - you out there? Am I all wet on this??:D

Geek 21st February 2008 02:11 AM

*the skeptics look at the new EDCOR with fear as they tap it with a stick*
:D :clown:

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