EDCOR Releases Line of Guitar OPT's

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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
 
ErikdeBest said:
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:
 
ErikdeBest: I´ve never purchased anything from Edcor personally, the two sets of transformers that I´ve bought this far has been from two different group buys here in Sweden.
I didn´t 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

Member
2003-10-20 2:43 pm
Sydney
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?

Chris

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

http://www.edcorusa.com/products/transformers/cxpp/index.html

http://www.edcorusa.com/products/transformers/cxse/index.html
 

Geek

Member
2004-09-08 7:17 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.

Cheers!
 

kevinkr

Administrator
Paid Member
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
 
So if these are good for hifi they ain't going to be all that good for a guitar amplifier...

I agree with Kevin on this for most guitar amps. For the typical electric guitar amp transformer you need to cheapen it up a bit, quite a bit. Or, in true Tubelab style, crank up the applied power to one of these. Some of the characteristic sound in many vintage amps was obtained by using too small an OPT (especially Fender). However if you are building an amplifier for an acoustic guitar, or a 12 string, a very clean sound may be desired and a HiFi type OPT may be desired. The type of speaker used plays a big part of the sound equation too.

And as a corollary if they are good for guitar use they won't be all that good for hifi..

A typical guitar amp transformer loses about two octaves on the low end since the lowest frequency a guitar can produce is 82Hz. This is usually accomplished by leaving out most of the iron. In order to save cost there is usually no interleaving, thus killing off some of the high end. Some guitar amp transformers are pretty bad, and some can actually pass audio with HiFi specs, at reduced power levels. Several years ago I bought a bunch of surplus transformers from the closing of the ADA guitar effects company. They were "80 watt" P-P OPT's that weigh in at about 5 pounds each. They work so well that I have a pair in my 300B P-P amp. They are maxed out at 25 watts though.

Those 1700 ohms units are quite interesting as they might be a good match for some low rp tubes......certainly interesting for low power cathode follower amps!

I recently acquired some 7233's and I have some Russian 6S19P's on order. I was planning a small SE cathode follower, but didn't know where to find the OPT. Now I know. I need to run some simulations to determine the best choice. With a little creativity you can get 850 ohms, 1250 ohms, or 1700 ohms. Then I will order a pair. If the HiFi experiment fails I can always build a guitar amp.

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...

The Edcor XSE 15-8-5K caries a 70 Hz to 18 KHz rating. I measured 16 Hz to 46 KHz. This is the frequency response at 1 Watt. There are some saturation effects that prevent operation below 70 Hz at 5 watts. The 15 watt rating seems more like something that you would see in a guitar amp. Maybe the new line of transformers are just more realistically rated.
 
Geek said:
*the skeptics look at the new EDCOR with fear as they tap it with a stick*
:D :clown:

I'm not a skeptic at all, I like all of the other edcor transformers and recommend them frequently for various projects. It's just that I have not had good luck with guitar output transformers made by vendors who specialize in good quality hifi designs - they need to take a different mindset which can be very uncomfortable if you are trying to make the best quality product.

Transformers for acoustic guitar amplification are another matter, good hifi transformers work well here.
 

Geek

Member
2004-09-08 7:17 am
Hi Kevin,

kevinkr said:
It's just that I have not had good luck with guitar output transformers made by vendors who specialize in good quality hifi designs - they need to take a different mindset which can be very uncomfortable if you are trying to make the best quality product.


Kind of like a winery that makes a really good red - the whites usually suck and vice versa?

Brian's a smart guy over there. I can't wait to try some and see.

Cheers!
 

MQracing

diyAudio Member
2005-10-08 4:11 pm
www.magnequest.com
All this talk that guitar amp transformers have to conciously be built "poorly" by hifi standards to sound good in guitar amps----

perhaps I could offer a different view and some counterexamples;

check out (and they have some nice eye candy on their site)

www.theairtightgarage.com

they use "hifi" tranneys made by us... and seem to like them pretty well.

check out www.allessandro-products.com

George has gotten (as I understand it) some killer reviews in Guitar Player magazine and has a super clientele list of some pretty accomplished musicians. Again--- good quality output transformers are what he gets from me.

One of the legends in the guitar amp world--- Alexander Dumble has the distinction of being the last customer Peerless built a new design vacuum tube output transformer for. It was rated at 150 watts. Was quite sophisticated with tri-filar secondary windings--- a lot of interleaving. Top end response past 100khz at minus 1 db.

here is a wikipedia entry on the famous Dumble amps

http://en.wikipedia.org/wiki/Dumble_Amplifiers


Also--- realize that SUNN amps used stock Dynaco output transformers and their amps "rocked" many a house over the years.

And lastly--- for another contemporary guitar builder using quality outputs--- in this case single ended outputs and with amps up to the 25 watt range check out;

www.guitar-engines.com

and here is a quick review I found on the six moons site of one of Gordon's guitar amps;

http://www.6moons.com/audioreviews/wavelength/junior.html


the guitar market is larger and more variegated than to make universal statements about how the products are made or what qualities the designers of guitar amps are looking for when they buy output transformers for their creations.

Mike
 
I guess my big question is has anyone actually confirmed that the Edcor guitar series transformers are lower quality in any way? Or are they just designed with a more suitable core & interleave for guitar use.

I have used a heck of a lot of Edcor XSE & XPP OT's in various guitar amps and have just loved the big full extended sound.

As MQracing mentioned, some of the most sought after amplifiers ever made used HiFi grade transformers. Trainwrecks and Dumbles command huge money in the current market.

I have also been running a couple of the new Hammond Guitar series OT's the past few weeks and they stand up great to the OEM's I have swapped out.

I feel Edcor has just realized that the DIY guitar amp market has and is growing, Combine that with their great prices and they can easily make this a viable product line.

I can still remember the first time I called Phyllis at Edcor to order some XSE's for guitar amp replacements, She in not so many words thought I was nuts!
Once the low cost SE guitar amps like the Valve Junior and the Champ 600 hit the shores and stores, guys went nuts modding them and upgrading the OT's to various brands. Edcor XSE's turned out to be a popular alternative in both quality and price.

Trout
 
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