• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Suggestion for push pull output transformer.

Let's say I have a significantly smaller budget, and lower standards-- I don't want distortion or frequency response to get in the way of listening to music, but I won't be intentionally critical when listening and I don't even have something ultra-high end to compare to.
My motivations for building an amp are mostly the fun of the project and novelty of designing my own circuit, but I want the result to be "pretty good" (at least, not to be held back by the OPT).

The class of transformer I'm looking at would be a Hammond 1650R or an Edcor CXPP100 (5k). I remember reading something bad about the 10k ohm 100W Edcor, but this sounded like a specific problem with the high-impedance model (which is apparently a tough thing to design).

Of these two, are there any serious "this will sound like CRAP" kind of warnings? Is one of these clearly better than the other?

Considering shipping cost they're very similar prices.
 
I am about to acquire a pair of Heyboer-wound copies of a Peerless S-265-Q. Have used these before, and they are bloody excellent. Cost is less than $300/pair thanks to NC winders and stackers...:) I also have a pair cloned form a Peerless S-271-S, a 5k a-a, 20-20 Plus model good for 80 Watts. Probably going to be loading a pair of big TV sweeps...
cheers,
Douglas
 
Interesting, it's hard to find listings of Heyboer prices and products since they're only kept in stock by Mojotone which are mostly guitar-amp parts. If I just contact Heyboer directly, they'll give info or price quotes?
 
Not much info on Heyboer-wound. Seems like it's for guitar amps.

On the subject of guitar amps, I experimented comparing Classic Tone Bandmaster output transformer with Weber Marshall Plexi 50W transformer. The size, dimension and everything are different. They sounded EXACTLY the same far as I concern. Just like tubes, I can swap different brand tubes and it ain't making a dent of a difference. Far as I concern, for guitar amps, there are more hot air than anything. I can say that because I designed a few tube guitar amps( not copying and change a few values and called my design. I mean totally different design). It's the design that change everything, not what is used in the amp. I use ceramic caps, metal film resistors, cheapest tubes from ebay express and a cheap Classic Tone output transformer. I don't use choke either. I use cheap Illinois filter caps, not the exotic caps.

Just like I design distortion pedals also. People talk about germanium transistor and diodes. I designed my pedals with Schottky diodes.....the new generation diodes!!! People love it!!! I had three identical pedals, one use Schottky, one germanium and one just 1N4149, the Schottky won!!!! But people keep talking about germanium!!!!
 
jharris said:
...If I just contact Heyboer directly, they'll give info or price quotes?
Click to expand...

Yeah, I've used their contact form on the website on a few occasions. I sent my requirements/specs and they typically responded within a couple business days with a quote.

So far I've done just power transformers from them but don't see any reason outputs would be any different...other than perhaps more things to specify.

If they have a formula already baked for a clone then I'd imagine just ask for that.
 
I don't think I want to go with custom build transformer, I rather buy ready made so it's more repeatable if I want to buy again in the future.

There's really not that many companies that sell audio output transformers, I went on Google over and over, seems like we cover most of them already. I know there are exotic stuffs that one has to hunt for, or some really old antique used ones. I don't think I want that. It has to be reproducible, and consistence. On top of that, there are just too many snake oil going on, like the $100 cap, "special" resistor and exotic tubes..................

I think about $300 dollars is all I want to spend. As I said from the experience of guitar amps, it did not make a damn of a difference. But I want to have an open mind and give it a fair shake, since every one said the OT is the key, so I am going to spend the money to hear it with my own ear.

May be I should buy a Hammond or Edcor of the same primary impedance and compare. Then I can have real experience to comment on this. If the $300 OT gives me the sound quality up to my expectation, I will try the cheaper OT and see how big a difference. If the $300 OT still not up to par, then I just go back to SS world.
 
That's each right I believe from what you've said? From my experience with cheaper & better vintage I would say you may wasting your time & $ on the bottom $ ones the way you were worried about distortion measurements as for sure the better ones will have less plus you will notice a little better freq. response! The Lundahls should be fine and not too pricy!

Found a Trans. Manufactures List:

http://www.diyaudio.com/wiki/TransformerSuppliers
 
Shadowdog said:
That's each right I believe from what you've said? From my experience with cheaper & better vintage I would say you may wasting your time & $ on the bottom $ ones the way you were worried about distortion measurements as for sure the better ones will have less plus you will notice a little better freq. response! The Lundahls should be fine and not too pricy!

Found a Trans. Manufactures List:

http://www.diyaudio.com/wiki/TransformerSuppliers
Click to expand...

Thanks for the info.

One think I am reluctant to commit to Lundahl is, their transformers seems to design to go onto a pcb. I want to do wire and terminal block. In fact, my first design is going to go onto a wood board. It would be nice to have one that can stand alone.

I have no problem designing and layout pcb, I do it in my SS amp design. Problem is it's very hard to experiment on pcb, changing the circuit is hard. On top, for heavy components, one needs thicker pcb over 2mm thick to have the rigidity to hold up the components. Also the board has to be big to accommodate the tubes and OPT. The pcb can get expensive to make. Simple circuit like tube amps don't need pcb. I did a 12" X 3", two layer, 2mm thick pcb for my SS amp, it's over $150 for 20pcs.( it's not much cheaper for 5 or 10 pcs). The board for 2 channel with OPT and tubes can easily by 12" X 10", it's going to be a lot more. You literally can count the area to get the price. I don't even think 2mm is thick enough to hold those transformers.

Too bad no distributor for Sowter in US.
 
Not right on the Lundal's designed to go one a PCB, but they do have a wire hook up on sort of little PCB setup. As for mounting they are too big and heavy to bolt on a PCB so they must be mounted like any other transformer.

They also sell covers for them too!

As for Sowter look at the USD!

Also look at Hashimoto as they are sold in the US! They are however more like $500+ ea in the size you want! They may be worth the price given their rep. however and it seems you do want quality sound!
 
Thanks Shadowdog

If they sell covers, then that will do it. I know they can be mounted standing up, but I worry about exposing the HV terminals. Hope the cover looks good. My final amp has to look good.

What do you mean by look for Sowter at the USD? I checked, it's about 240 british pounds before shipping and VAT.

Wow, those Hashimoto are expensive. Like $1000 a pair.
 
Alan0354 said:
I don't think I want to go with custom build transformer, I rather buy ready made so it's more repeatable if I want to buy again in the future.
Click to expand...

They keep the formula on file so they don't redesign it each time. If I want another one of the transformers I've bought from Heyboer I give them the part number and they build another to that same spec.
 
The USD is at a high point compared to other currencies, for instance, 33%+ on the CDN $ , and by the time I pay taxes & shipping from the US on said transformers they will cost Double!

No distributor for Lundal , Edcor etc, here either!

You don't pay VAT on items from the UK that's for those poor buggers!

You are lucky right now so take advantage!
 
whoaru99 said:
They keep the formula on file so they don't redesign it each time. If I want another one of the transformers I've bought from Heyboer I give them the part number and they build another to that same spec.
Click to expand...
I'm not even sure how I would get the specs to clone a transformer, there's so much complicated stuff going on like interleaving windings-- I've read repeatedly that slapping enough inductance in it to give bass response and calling it a day isn't good enough.

Would they need to have cloned a Hammond 1650R (or something else... I wouldn't have them clone a transformer I can still buy, but you get the idea) previously, or could I say something like 40hz-20,000hz, 100 watts, 5k ohms and they'll figure out how to make it happen?
 
jharris said:
I'm not even sure how I would get the specs to clone a transformer, there's so much complicated stuff going on like interleaving windings-- I've read repeatedly that slapping enough inductance in it to give bass response and calling it a day isn't good enough.

Would they need to have cloned a Hammond 1650R (or something else... I wouldn't have them clone a transformer I can still buy, but you get the idea) previously, or could I say something like 40hz-20,000hz, 100 watts, 5k ohms and they'll figure out how to make it happen?
Click to expand...

Generally, they take apart an original then recreate what they find.

And, no, there would be no good reason I can think of to clone a current off the shelf transformer.
 
A member on this forum had them try custom build PP ones and they didn't work out at all so they would have to have one to clone to likely be hopefully successful!
 
If I am that knowledgeable, I'll wind my own transformer. All I can give is the primary and secondary impedance, what else can I spec?
 
Core size etc. & materials. I think you would have to buy a big volume of materials & interleaving properly may be hard to do without equipment.

Maybe talk to winder & amp builder Patrick Turner in AUS whom I linked to earlier in this thread as he is a really nice guy as I emailed him back & forth a few yrs. ago, however he is battling Cancer for the last several years which is why he probably retired. He still has trans. listed on his site too! Maybe you can take over!

http://www.turneraudio.com.au/index.html
 
You must log in or register to reply here.
Back
Top Bottom