EDCOR XSE, GXSE and CXSE basic specs and measurements

[Shannon Parks]

Awesome work, Ed! Thank you.

Shannon

[EWBrown]

I started to wonder about all of the ramifications of "ratio-ing" various OPTs, like using a 10K:16 ohm OPT as a 5K:8 ohm, or an 8K:16 ohm as a 4K:8 ohm, as with some of the Edcors. And the behaviours of the various Hammond "Universal" SE and PP OPTs (namely the 125 series).

Who better to ask, but Mike from Magnequest. I'll freely admit here, that his knowledge on the intricacies of transformer design is of many orders of magnitude greater than mine. I just barely understand RDH3

Here is what he had to say about it (I had used the rather humble Hammond 125ESE as an example, as well as using an Edcor 10K:16 as a 5K:8)

Take the example of the Hammond trans with 9.58 H of pri L.

Ignoring many, many other considerations--- like copper current density,
insertion losses, parasitics, etc....

But just by looking at and evaluating what happens when you ratio a trans---

let's just consider it from this vantage point of the design having 9.58H of
primary L.

9.58 henries of L has the following impedances at these stated frequencies;

@ 20 HZ the inductive reactance will be 1204 ohms

@ 40 HZ the inductive reactance will be 2408 ohms

@ 80 HZ the inductive reactance will be 4816 ohms

@ 160 HZ the inductive reactance will be 9632 ohms

So, now at whatever low freq cutoff point you will accept take the inductive
reactance and put it in parallel with the reflected impedance (no matter whichor how many creative tapping games you want to play) and see what the "net" result is. The "net" being--- what is the effective primary impedance that the tube will be working into? And how reactive is it? How hard will it be to drive?

Is the shunt arm (i.e., the reactive component) larger than the purely resistive component?


The phase angle of the load--- i.e., the ratio btwn reactive vs resistive components will have a direct effect on the behaviour of your tube (i.e., the generator) in terms of both power delivery (i.e., insertion losses) as well as how much distortion the tube generates.


If it were possible to ratio transformers endlessly-- as an earlier poster suggested--- wouldn't transformer catalogs be relatively simple with perhaps one single offering per power level?


Well made transformers are finely tuned--- the wire sizes selected for a specific impedance, the insulation types and amounts selected for a specific impedance, the number of turns on the primary intimately related to the nominal design impedance.

When you ratio a transformer--- your essentially throwing all this good engineering out the window.


MSL

/ed B

[EWBrown]

CXSE25-8-5K SE output transformer

( Information courtesy of Justin Weber, in the G*S*G topic )

Wattage: 25W
Max. Current: 200mA
Primary (input) Impedance: 5K Ohms
Primary (input) DCR: 85 Ohms
Primary (input) Inductance: 50H
Screen/Grid Tap: 40%
Secondary (output) Impedance: 8 Ohms
Secondary (output) DCR: <1 Ohm
Frequency Response: 20~20K Hz., <1dBu
Weight: 10 Lbs

/ed B

[jamesdb]

50H is very good, isn't it? Is that comparable to other big name output transformers?

[Geek]

50H in any SE transformer is incredible..... would make the full power point just under 16Hz to reflect 5K (any local NFB around the output tube, or gNFB would lower that even more).

Cheers!

[Shannon Parks]

Here's my $18 open frame Edcor output measurements for the updated Budgie SE. Inductance measured with my Wavetek Meterman 37XR (now Amprobe 37XR) and the secondaries were unloaded. DCR measured with my 6.5 digit bench DMM.

Edcor GXSE5-8-5.5K (courtesy of Ty Bower)
190 ohms primary DCR
2.2 ohms secondary DCR
5.1H primary (secondary unloaded)
18 ounces

Edcor XSE10-8-5K
120 ohms primary DCR
0.25 ohms secondary DCR
2.87H primary (secondary unloaded)
18 ounces

Current OPT with bells for comparison:
Edcor GXSE10-8-5K
185 ohms primary DCR
0.6 ohms secondary DCR
6.7H primary (secondary unloaded)
27 ounces

Shannon

[Auricle]

Season's Greetings! I hope the jolly fat man left you all many goodies.

I ordered a pair of Edcor GXSE10-8-5K's, which arrived appropriately just before Christmas.

I am surprised by the unit-to unit variation. Inductance measured at 100Hz with Meterman LCR55

xformer 1
L = 9.4 H
R = 184 ohms

xformer 2
L = 10.3 H
R = 183 ohms

I am surprised by the inductance variation, especially in light of the closeness of the DC resistance measurements.

Is this acceptable? Any insights?

Regards,
Auricle

[Geek]

I dunno if we're also adding power trannies here for Duncan's PSUD?

XPWR132-120

Pri DCR: 0.9R
Pri Test Voltage: 123.5

HV DCR: 45.5R
HV @ Pri Test Voltage: 816

[jukingeo]

Hello, All

I know this is an older thread, but I have been looking into getting transformers for a Clementine Darling project and I been wanting to get some ideas in regards to those that have actually used these transformers and how close to the design specs they are.

While I currently have Hammond 125E (not ese) transformers, I am looking into something better yet staying under $40 per transformer. In searching for some transformers that have a better lower end response, I have come across the Edcor XSE which is very reasonably priced and rolls off at a lower 70hz as compared to the Hammond's 100hz. However for a few bucks more, I could get into the GXSE line and the are claiming this transformer goes down to 40hz, which is even better.

I looked to this thread as I was hoping there would have been some actual frequency response tests and some opinions on educated ears as to the differences in sound quality. I know for one, fellow diytuber Tom McNally has built many amplifiers and he would be one such authority I would turn to on this discussion.

However, seeing that this was a thread that possibly could answer my question, all I found here was a bunch of resistance and inductance tests and not much in terms of sound comparisons. That is more what I am looking for. So I am asking that question here if anyone can give me an idea of the differences are SOUND WISE in the XSE and GXSE lines....and by all means add the CXSE line as well. Otherwise I just will start a new post if I am barking up the wrong tree here.

Thank you,
Geo