Hi Folks,
With reference to an earlier post, I have decided to build this amplifier (a PSE 300b) -
http://www.audiodesignguide.com/my/pse2.html
The design requires a custom transformer with specs 2.5V-0-2.5V 4A / 2.5V-0-2.5V 4A / 100V 0.1A
Any ideas on custom transformer builders (ones in Australia would be particularly useful)- recommendations? Cost?
Any one know of an 'off the shelf' transformer that would so the job?
Thanks in advance,
Rob
With reference to an earlier post, I have decided to build this amplifier (a PSE 300b) -
http://www.audiodesignguide.com/my/pse2.html
The design requires a custom transformer with specs 2.5V-0-2.5V 4A / 2.5V-0-2.5V 4A / 100V 0.1A
Any ideas on custom transformer builders (ones in Australia would be particularly useful)- recommendations? Cost?
Any one know of an 'off the shelf' transformer that would so the job?
Thanks in advance,
Rob
Just use seperate trafos..
2x 5V CT for fils, and one little isolation trafo for the bias supply...
that's what i'd do at least. They'll be reasonably small, you can stuff them under the chassis or something...
2x 5V CT for fils, and one little isolation trafo for the bias supply...
that's what i'd do at least. They'll be reasonably small, you can stuff them under the chassis or something...
G"Day Rob,
Maybe try emailing Edcor www.edcorusa.com
They just quoted me about $56 for some power transformers, plus a once only $20 design fee. With the US$ so low at the moment, they are pretty cheap.
Cheers,
Chris
Maybe try emailing Edcor www.edcorusa.com
They just quoted me about $56 for some power transformers, plus a once only $20 design fee. With the US$ so low at the moment, they are pretty cheap.
Cheers,
Chris
Hi Chris,
The edcor guys seem like a good tip. They don't appear to do toroidals and i was looking at these for something a bit different..
Any experience or knowledge concerning the plitron transformers - they seem to do custom jobs and appear to include magnetic sheilding as well -
http://www.plitron.com/
Rob
The edcor guys seem like a good tip. They don't appear to do toroidals and i was looking at these for something a bit different..
Any experience or knowledge concerning the plitron transformers - they seem to do custom jobs and appear to include magnetic sheilding as well -
http://www.plitron.com/
Rob
G'Day Rob,
I think that some on this site have stated that they think that the high bandwidth of a toroidal transformer is not as good a choice as an E I transformer for the power supply as it passes too much hash from the power line in to the power supply of the amp. I will let others comment further on this.
If you are in to maths, Menno van der Veen has a bit to say about toroids in his book "Modern High End Valve Amplifiers Based on Toroidal Output Transformers" (google it).
If you are interested, I have a copy of this book that you are welcome to borrow.
I have not used the Edcor power transformers, but have seen a few designs on the web that have used them with no complaints. I have built two amps with Hammond 300 series power transformers that have been quite OK (some of the 200 series buzz apparently). I have just ordered a couple of power transformers from Edcor this morning. I changed my spec a little, the final design being dual 120v primaries for 50Hz, 330-0-330v 200mA, 6.3v 5A, 5v 3A secondaries and was quoted $63.51 plus a once only design fee of $20 (so if any one else needs a transformer with the same spec, no $20 charge for them). Shipping to Australia is two transformers per USPS flat rate box $39. All prices $US, but that is pretty much 1:1 with the $AUD now! I hope they will be OK, as they will be for a set of mono-blocks with a $600 pair of Tamura output transformers!
If you are still working out what components you are going to use, and you are looking hi-end, this site might be worth checking out http://www.obsinc-products.com/servlet/Categories?category=Transformers:Output+-+Single+Ended
From what I gather, Hashimoto is a well respected Japanese brand.
Interested in seeing this one progress!
Chris
I think that some on this site have stated that they think that the high bandwidth of a toroidal transformer is not as good a choice as an E I transformer for the power supply as it passes too much hash from the power line in to the power supply of the amp. I will let others comment further on this.
If you are in to maths, Menno van der Veen has a bit to say about toroids in his book "Modern High End Valve Amplifiers Based on Toroidal Output Transformers" (google it).
If you are interested, I have a copy of this book that you are welcome to borrow.
I have not used the Edcor power transformers, but have seen a few designs on the web that have used them with no complaints. I have built two amps with Hammond 300 series power transformers that have been quite OK (some of the 200 series buzz apparently). I have just ordered a couple of power transformers from Edcor this morning. I changed my spec a little, the final design being dual 120v primaries for 50Hz, 330-0-330v 200mA, 6.3v 5A, 5v 3A secondaries and was quoted $63.51 plus a once only design fee of $20 (so if any one else needs a transformer with the same spec, no $20 charge for them). Shipping to Australia is two transformers per USPS flat rate box $39. All prices $US, but that is pretty much 1:1 with the $AUD now! I hope they will be OK, as they will be for a set of mono-blocks with a $600 pair of Tamura output transformers!
If you are still working out what components you are going to use, and you are looking hi-end, this site might be worth checking out http://www.obsinc-products.com/servlet/Categories?category=Transformers:Output+-+Single+Ended
From what I gather, Hashimoto is a well respected Japanese brand.
Interested in seeing this one progress!
Chris
Hi Rob!
Maybe an R-Core trafo could be interesting. This one is very close to your spec. and it is intended fro 300B use. The price is 80 $ US/pc. Have a look: http://www.vt4c.com/shop/program/main.php?cat_id=55&group_id=7&hit_cat=
Or you could ask: http://www.ae-europe.nl/ . This company is recommended by Triodedick who claims that AE-Europe.nl is the best trafo-maker in the world (OK, his words!). Drop them an email - they make exactly what you want. Delivery time for customized trafos is approx. two months.
TriodeDick: www.triodedick.com
Kind regards
Karsten
Maybe an R-Core trafo could be interesting. This one is very close to your spec. and it is intended fro 300B use. The price is 80 $ US/pc. Have a look: http://www.vt4c.com/shop/program/main.php?cat_id=55&group_id=7&hit_cat=
Or you could ask: http://www.ae-europe.nl/ . This company is recommended by Triodedick who claims that AE-Europe.nl is the best trafo-maker in the world (OK, his words!). Drop them an email - they make exactly what you want. Delivery time for customized trafos is approx. two months.
TriodeDick: www.triodedick.com
Kind regards
Karsten
Hi,
Try Heyboer Transformers
http://www.heyboertransformers.com/index.shtml
I ordered 2.5V custom filament transformers (with electrostatic shield between windings) for my 2A3 amps from these guys. Service is very good and quality is excellent.
Regards, Irakli
Try Heyboer Transformers
http://www.heyboertransformers.com/index.shtml
I ordered 2.5V custom filament transformers (with electrostatic shield between windings) for my 2A3 amps from these guys. Service is very good and quality is excellent.
Regards, Irakli
I have used one of those R core transformers on my girlfriend's amp, and it buzzes. Next amp is a little 6BM8 SE with my son using that 50mA+50mA R core that is at the top of that link, will report if it buzzes too!
These guys in Hong Kong have some interesting stuff too. Have seen their shop. The EI transformers look to have a shield. Used one for the little experimental PP in my study. Works well, no buzz, their is no hum in the amp, but the transformer itself is not the prettiest. http://eshop.diyclub.biz/
These guys in Hong Kong have some interesting stuff too. Have seen their shop. The EI transformers look to have a shield. Used one for the little experimental PP in my study. Works well, no buzz, their is no hum in the amp, but the transformer itself is not the prettiest. http://eshop.diyclub.biz/
Thanks for the advice Chris - I will steer clear of these then.
Thanks Irakli, I now have two custom manufacturers to check out. Should be able to convince one of them to make up a custom transformer for me!
Rob
Thanks Irakli, I now have two custom manufacturers to check out. Should be able to convince one of them to make up a custom transformer for me!
Rob
Give Southern Electronic Services in Melbourne a call, I've not used them but have heard they are ok. The postage from Melbourne might be a little better too... Their website says they do custom and valve work.
link
Let people here know if you use them, it would be interesting to know how they compare.
link
Let people here know if you use them, it would be interesting to know how they compare.
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