Good inexpensive OPT transformers or going hybrid.

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Good inexpensive OPT transformers or going hybrid.

Postby jukingeo » Sat Mar 13, 2021 12:26 pm

Hello All,

It has been a while since I had been messing with tube based audio amplifiers, and I have been thinking about getting back into it. I had a few amplifier projects in the works, but in all, I do have to get output transformers for some of them. There was a 6L6 / 807 project I was working on and I bought one Hammond 1650F output transformer for that. I remembered paying around $60 for it. Now the same transformer costs $100! Across the board I am bewildered in how much the prices have jumped up in output transformers in just a few years time. I remember there was an affordable company by the name of "James" that made decent transformers, but they are gone.

So I am curious if there are still transformer companies out there that have a decent product for an affordable price, as it seems Hammond is now getting too expensive.

As an alternative, I don't know what advances (changes) had been made in the diytube field of decent performing hybrid amplifiers. I know many purists don't like 'sand' in the signal chain, but it is clear that with rising prices of output iron, I am looking for lesser costing alternatives. Could a pair of output tubes drive a set of mosfets and that could drive a speaker instead of going through a transformer? If so, how would it sound?

I still like to keep things simple, and prefer to use transformers, but from what I have seen with popular transformer brands, they are getting too expensive.

Any input would be appreciated on this.

Thank you,

Geo
Exit Light, Enter Night, Take My Hand...We're off to Never Never Land.
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Re: Good inexpensive OPT transformers or going hybrid.

Postby HotRod » Mon Mar 15, 2021 1:06 pm

Have you checked AnTek?
Noticed that they started winding output transformers again.
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Re: Good inexpensive OPT transformers or going hybrid.

Postby jukingeo » Wed Mar 17, 2021 9:18 pm

HotRod wrote:Have you checked AnTek?
Noticed that they started winding output transformers again.


I have noticed that Tom McNally has been using a AnTek donut transformer in his latest Darling projects, and I ended up buying one for my Darling project as well. I didn't know they had output transformers as well. I ended up going with Edcor, even though I initially stayed away from them because of the long turn around time. But I had found their prices on the XSE and GXSE lines very reasonable and I ordered a pair of the latter (GXSE-15-8-5k) just last night. So the long wait begins!

However, I had ordered the AnTek Transformer four days ago, and I had already received it!

I will take a peek at their output tranformers for the future. Hopefully they are priced well too.

Thanks,
Geo
Exit Light, Enter Night, Take My Hand...We're off to Never Never Land.
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Re: Good inexpensive OPT transformers or going hybrid.

Postby Thermion » Thu Mar 18, 2021 5:29 am

jukingeo wrote:
But I had found their prices on the XSE and GXSE lines very reasonable and I ordered a pair of the latter (GXSE-15-8-5k) just last night. So the long wait begins!


I think you made a good choice on the Edcor GXSE-15-8-5k outputs. I have used those same outputs in a couple of Chubby Clementine projects with good success. As well as a couple of SE guitar amps. I am planning to build Clementine based integrated amps for my two sons for Christmas this year. I placed my order with Edcor on Dec 25th and still have not received the transformers. It was a fairly large order, 4 outputs, two power and two chokes. They seem to be having some delays due to COVID.

The transformer prices spiked a few years ago when copper and iron prices were going up. They seem to be holding steady now. Edcor and Hammond are still the least cost options. I prefer Hammond for most of my projects, especially PP designs. I only use the Edcor for low wattage SE amps.

Jonathan
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Re: Good inexpensive OPT transformers or going hybrid.

Postby jukingeo » Sat Mar 20, 2021 10:21 am

Thermion wrote:
I think you made a good choice on the Edcor GXSE-15-8-5k outputs. I have used those same outputs in a couple of Chubby Clementine projects with good success. As well as a couple of SE guitar amps. I am planning to build Clementine based integrated amps for my two sons for Christmas this year. I placed my order with Edcor on Dec 25th and still have not received the transformers. It was a fairly large order, 4 outputs, two power and two chokes. They seem to be having some delays due to COVID.

The transformer prices spiked a few years ago when copper and iron prices were going up. They seem to be holding steady now. Edcor and Hammond are still the least cost options. I prefer Hammond for most of my projects, especially PP designs. I only use the Edcor for low wattage SE amps.

Jonathan


Well, I have used Tom McNally's site as a reference considering he has built so many amplifiers and then sold them. So I figured his choice would be a good advice to follow. Comparing amplifiers on his page, it seems he favored the Edcor transformers the most for his Clementine amplifiers with the XSE and GXSE series for the Darlings and specifically, the GXSE-15-8-5K for his "Chubby" Clementine projects. So I bought those to use as a reference for both a Darling and a Chubby project. So with one channel using the GXSE and the other with another transformer that I could test, I can do sound comparisons. In the end, the final design for the Darling would most likely use a smaller transformer as I do want the Darling to be a more compact design. However, if the difference in sound is significant then I would stick with the GXSE -15-8-5k for both projects.

As for the JE Labs EL34 SE project I am working on. That one I have some serious pieces of iron for. I had initially wanted to put this amplifier on an ST-70 chassis, but I think the iron might be too heavy for it. I will see.

That is really it for my projects for now...three amplifier designs with all being SE designs under 10 watts per channel.

I am a bit shocked to hear of your dealings with Edcor in that your shipment was placed in December and you still have not received your order. In fact it was my reading of your answer that prompted me to create two orders with both only having two identical transformers in it. It could mean that because they have to retool their set up as per transformer, they might be holding off on your shipment until they can get all of the transformers done. It is my guess that it is probably the chokes that are holding your order up as I don't foresee them tooling up for choke runs often. So it could very well be that your order might be done save for one transformer that is holding the whole thing up. So I decided that I will place the second transformer order later on. While that might cost me more in shipping, it might reduce my wait time in the event that the transformer I am ordering is in a 'holding pattern' before Edcor gets around to tooling up for that transformers particular run.

BTW, I know you are a regular here. What has become of Shannon Parks? I don't see he is around here any more and it appears all of his pcbs are discontinued!

Thanks for the info.
Geo
Exit Light, Enter Night, Take My Hand...We're off to Never Never Land.
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Re: Good inexpensive OPT transformers or going hybrid.

Postby Thermion » Sun Mar 21, 2021 5:41 am

junkgeo wrote:
BTW, I know you are a regular here. What has become of Shannon Parks? I don't see he is around here any more and it appears all of his pcbs are discontinued!


Geo,

You must feel like you've been in a coma for 6 years and just woke up. There have been many changes. As far as Shannon, I answered your question in the Posiden board so check there.

You are right that this forum is not very active at this point and is more of an archive of information, so responses will be slow. Don't expect the level of activity we had in the past. Sadly, Ed Brown passed away in 2017. In many ways he was the "glue guy" for this forum answering many questions and introducing new ideas and projects. There are still a few of us that frequent the site, although any momentum toward reinvigorating the posting was hampered by the fact the the site was down for almost a year because of hacking attacks. I was checking it periodically and was pleasantly surprised to see it back up. Along with your recent posts. So many of the others may not know it is back up yet.

It has been 11 weeks so far on my Edcor order. I doubt it has anything to do with tooling and certainly not the chokes which are very straightforward to wind. It is probably more about supply chain problems or labor shortages due to COVID. I expect they will show up soon.

I'm curious to see how your transformer listening tests go. In my experience the output transformers don't significantly affect the character of the sound of an amp unless they are pushed to saturation and distortion. I have found the coupling caps to have the most affect followed by tube rectification and choice of resistors.

Regards,
Jonathan
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