Output SE Transformer Question

[John L]

I know this has been covered before, but don't know where to look. Here's what I need.

The Hammond 125 series gives a full frequency response of 20 to 20K on its spec sheet.

The Edcor XSE and GXSE series have ratings of 70 to 18K, or 40 to 18K on its spec sheet.

Does this mean the former is really going to cover a better response through the amp and speakers? In other words, is the extra cost for the Hammonds really justified over the Edcors?

I'm getting ready to pick out materials to modify an S-5 K-12G, which I have been spending a good deal of time checking out as my first real home made tube amp. And if there is no real discernible difference, the Edcors are almost too good to pass up.

Sorry for my ignorance, but I have to begin somewhere.

[tubelab.com]

The Hammond 125 series gives a full frequency response of 20 to 20K

No it doesn't:

Frequency response: 100 Hz. - 15 Khz at full rated power (+/- 1db max. - ref. 1 Khz).
For full frequency response (20 Hz. to 20 Khz.) - see our 1627-1642 series.

It says to use their better transformers for full frequency response.

I have both of these transformers. They will both cover 20 Hz to above 40 KHz at low power levels, about 2 watts. They will both show signs of saturation above 5 watts. The difference is in the price, delivery time, and the way they are tapped. The Edcor has a UL tap, the Hammond does not. The Hammond has a multi tapped secondary to allow different impedance ratios, the Edcor does not. The Hammonds are in stock at distributors, the Edcors are built to order and take weeks to get.

Note that both of the transformers you linked to are for SE (single ended) applications only. I believe the S-5 is push pull although I have never seen one. Make sure before you get the wrong transformers.

[John L]

Originally Posted by tubelab.com

No it doesn't:



It says to use their better transformers for full frequency response.

I have both of these transformers. They will both cover 20 Hz to above 40 KHz at low power levels, about 2 watts. They will both show signs of saturation above 5 watts. The difference is in the price, delivery time, and the way they are tapped. The Edcor has a UL tap, the Hammond does not. The Hammond has a multi tapped secondary to allow different impedance ratios, the Edcor does not. The Hammonds are in stock at distributors, the Edcors are built to order and take weeks to get.

Note that both of the transformers you linked to are for SE (single ended) applications only. I believe the S-5 is push pull although I have never seen one. Make sure before you get the wrong transformers.

You're just the man I was hoping to see here.

But first, I agree, I really shouldn't have mixed the two up. I also have a good S-E project on the horizon, and have too many open tabs on my Opera browser,.....and my brain.

So setting aside my thoughts of S-E goodies, what would you recommend on this little P-P fellow that so many people love to play with? I've been to so many sites I can't keep track of them all. I've pretty much settled on cap replacements, after having read The Great Capacitor Shootout: perhaps either Auricap or Solen FastCaps. Both showed up very well in the shootout, but the Auricap is about double the price.



Oh, one other thing. I have been going to your home page, off and on, for some time now. And I am confused. Are you pretty much up to speed there, or still playing some catch-up? I ask this because I want to come up with an S-E project for my second go. After I put the K-12G into a nice case and get it ready for my grandson, I'm going to want to take the S-E on as a non kit project.

Are your Tublab SE, and the Simple SE PCBs still available? I know I am getting a bit ahead of myself, but I know pretty much how I want to approach this thing. And I have always enjoyed going through your site.

I remember seeing your two console radios, which you converted to speaker cabinets, and was impressed. In fact, I have one nice Philco(I think its a 39-180), and will need to come up with a nice second one.

[tubelab.com]

what would you recommend on this little P-P fellow that so many people love to play with?

I bought a truckload of P-P OPT's about 10 years ago to build guitar amps. I have been using them in almost all of my projects including HiFi amps, so I have much less experience with what's available in new P-P OPT's. I got a pair of the cheapest Edcor P-P OPT's a few years ago for a little project and I was less that impressed, but I think I was expecting too much from them. I would expect something from their GXPP line to be better than the stock transformers, but I haven't tried them myself.

Are you pretty much up to speed there, or still playing some catch-up?

No, I am way behind the times and playing catch-up. I spent musc of the last two years dealing with dying relatives in distant places and Tubelab got ignored. I didn't get much time to light up the tubes and my website hasn't been updated in about 2 years. Both my mother and my mother in law passed last year, and the legal hassles are finally winding down. My current work schedule doesn't leave much tube time during the week, but I am finally making headway.

I have and intend to keep stock of all 3 of my PC boards. There is the SSE board (legal action now doesn't allow me to use the word Simple together with the common abbreviation for Single Ended any more) the Tubelab SE (or TSE) and the Simple P-P (SPP). I also have a parts kit for the SPP.

Since I haven't had much time for the web site, I have my own forum here on diyAudio. I can't always get to it during the workday, but I can often post from my smartphone. It is far more current than my website.

Tubelab - diyAudio

[John L]

Shadowdog, over at AudioKarma, recommended I check out your Simple P-P(EL84) before ordering the kit. If you already have the parts kit for it, it may be better for me to help you bring down your stock?

I'll try to locate it. But if you have the link, I'd appreciate it.

Thanks George

[rmyauck]

I called myself shadowdog at AK, but can't change that now! The PP board isn't mentioned for sale on the tubelab site , but this should be what your looking for.

Board Availability

I like that Philco! I have a SW AM/Shortwave console to restore with not as nice a cabinet, but the same year of manufacture. I bought in 85-86 and it worked after replacing a cap for years when I played it once in a while. I powered it up with a variac a few yrs ago and realized I should recap it etc. totally as dial lights got bright right away and it had poor sound with low volume.

Have fun building!


Randy

[John L]

Originally Posted by rmyauck

I called myself shadowdog at AK, but can't change that now!

Board Availability



Have fun building!


Randy

Ahh-Haa, you rascal........eh?

Well, I'm now up to page 28 of the "Tubelab Simple P-P" thread, up to the point where Ian, from down under, has completed his project. I note that he has used an Antek 2T-300, which is a great bargain for a power trans. But I also note that the Edcor XPWR131-120, which George had earlier recommended, puts out a higher voltage rate.

Has anyone tried the XPWR131 yet? And if so, how does it perform?

I'm still playing catch-up, and won't get there until later this weekend, sigh.