Best value output transformers
« on: June 09, 2020, 03:01:31 PM »
I'm looking for some decent and reasonably priced line level output transformers for a mixer project. The mixer is an API style design but I don't necessarily need transformers that are exact API clones - they just have to perform well and not break the bank.

That said, I have looked at the CAPI 2623 clones and while I'm sure they sound great, they are a a bit on the pricy side when you add shipping to Europe and customs fees.

I'm wondering if anyone has experience with any of the "standard" Edcor output transformers? They are pretty cheap and they have resellers in Europe...


wlinart

Re: Best value output transformers
« Reply #1 on: June 09, 2020, 03:14:33 PM »
Maybe try to find a lot of haufe, pikatron, or one of the other brands of older transformers? Sometimes you can get great deals on those.

ruffrecords

Re: Best value output transformers
« Reply #2 on: June 09, 2020, 06:19:30 PM »
Edcor make great transformers but they are limited to M6 grain oriented steel cores. These are OK for many purposes but the main stream manufactures tend to add a proportion of more exotic laminations which improves distortion but also significantly increases the price.

If you want really good quality output transformers at a reasonable price in Europe look no further than CArnhill.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Best value output transformers
« Reply #3 on: June 10, 2020, 07:59:09 AM »
Although I'm sure Ian is right about Carnhill transformers, I really dislike the idea of making my buying decisions on manufacturer reputation and price alone. I like to know what I'm (not) paying for.

As opposed to Carnhill, Edcor actually publishes specs on frequency response and THD for their transformers (nothing about phase shift though). Looking at their PC Series which is available in a number of ratios, frequency response is pretty flat and THD is below 0.02%... certainly not great but not terrible either. They cost 11 yankee bucks direct from Edcor.

I actually don't think that 0.02% THD in and by itself would be a problem for me... as long as it is pleasant sounding and the frequency response is linear. If I want clean, I'll just stay in the box or use THAT line drivers. The main purpose of the mixer is to add a bit of mojo (i.e. pleasant, subtle distortion) that can be a lot of work to get right with plugins.

Does anyone have any idea about THD in the Carnhill output transformers?

ruffrecords

Re: Best value output transformers
« Reply #4 on: June 10, 2020, 06:13:32 PM »
The Edcor  PC series has a maximum input voltage of 5V rms which is 16dBu. Is that enough for your purpose. The Carnhill ones will operate up to +26dBu which is nearly 16V rms.

Edcor distortion is quoted as 0.05% at 1KHz. No level is specified so this figure is pretty meaningless. In any case mid band distortion in transformers is not usually very high. Where is matters is down at 20Hz where the flux reaches its maximum. Very few transformer manufacturers quote a figure at 20Hz.

Low frequency performance in transformers is mostly down to core size and signal level

I have made extensive distortion tests of Carhnill ( and other) output transformers. I can tell you that Carnhill output transformers I have tested at +16dBm output will achieve around 0.03% distortion at 1KHz and 0.16% at 20Hz.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Best value output transformers
« Reply #5 on: June 10, 2020, 07:37:09 PM »
The Edcor  PC series has a maximum input voltage of 5V rms which is 16dBu. Is that enough for your purpose. The Carnhill ones will operate up to +26dBu which is nearly 16V rms.

Right, I missed that... 16dBu/5V RMS is certainly a bit low, so this is one good reason to pay more.

Edcor distortion is quoted as 0.05% at 1KHz. No level is specified so this figure is pretty meaningless. In any case mid band distortion in transformers is not usually very high. Where is matters is down at 20Hz where the flux reaches its maximum. Very few transformer manufacturers quote a figure at 20Hz.

There are a couple of graphs in the "Product Files" section that show distortion across the frequency spectrum (there is actually quite a bit of it in the lower mids). Level is still not specified though.

I have made extensive distortion tests of Carhnill ( and other) output transformers. I can tell you that Carnhill output transformers I have tested at +16dBm output will achieve around 0.03% distortion at 1KHz and 0.16% at 20Hz.

Very interesting. Can I assume that this applies to all Carnhill (output) transformers, or are there significant differences between models?

rackmonkey

Re: Best value output transformers
« Reply #6 on: June 10, 2020, 10:50:54 PM »
The original 2503 output transformers on the 312/325 cards had all steel laminations. The fact that Edcor only uses M6 only serves to make them sound closer to the original. I know you said you're not looking to necessarily create exact clones, but it's a reference that may or may not help in the selection process.

The PCW series is only a couple of yankbucks more than the PC series, and is rated at 1/2 W (+27 dBm), as is the WSM series. Don Audio carries Edcor in Europe, at a premium vs US prices. Don't know if Don is a better deal or not, once you factor in overseas shipping and VAT.

By all means, look closely at the Carnhills. Ian has data I've never seen before for those. I have been happy with Carnhills on my Neve clones. Prices are good even for US buyers. But there are pretty cheap options other than the PC series in the Edcor line and they are nice transformers. And if steel is what you're after, it's hard to beat them.
Whether you think you can or you think you can't, you're probably right.

Re: Best value output transformers
« Reply #7 on: June 11, 2020, 03:38:04 AM »
The original 2503 output transformers on the 312/325 cards had all steel laminations. The fact that Edcor only uses M6 only serves to make them sound closer to the original.

Interesting. Slightly cheaper at Don Audio than the Carnhill ones from Audio Maintenance, but not much. Still, it's nice to have the  option to buy a larger batch direct from Edcor and save some money.

I think I'll buy an Edcor from the Don and see if I like it or not :-)

ruffrecords

Re: Best value output transformers
« Reply #8 on: June 11, 2020, 04:38:21 AM »
Very interesting. Can I assume that this applies to all Carnhill (output) transformers, or are there significant differences between models?
I have not tested all of Carnhills offerings but there is a whole range of un-gapped types with different ratios all based on the same core so I would expect them all to perform similarly. Bottom line is core cross section and number of turns is what counts for LF performance. Compare the dimensions of the Edcor PCW and the Carnhills and judge for yourself.

I have nothing against Edcors. Their nearest equivalent to the Carnhills is the XSM series and I have used trhese in place of Carnhills in the past. In those days I only made distortion measurements at 1kHz and there were comparable with the Carnhills but I do not know how good their low frequency distortion performance is. Notice how in the product files the THD is A weighted which significantly improves the figures at low frequencies and as you say there is no level quoted.

By the way, the Carnhills are also M6 cores.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruffrecords

Re: Best value output transformers
« Reply #9 on: June 11, 2020, 04:46:09 AM »
Interesting. Slightly cheaper at Don Audio than the Carnhill ones from Audio Maintenance, but not much. Still, it's nice to have the  option to buy a larger batch direct from Edcor and save some money.
I thought this too but it is not the case. The shipping charged by Edcor to Europe plus the VAT you pay on import effectively doubles their price. I don't know how Don does them so cheaply.

Cheers

an
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


 

Related Topics

  Subject / Started by Replies Last post
5 Replies
1399 Views
Last post July 13, 2005, 02:00:12 PM
by [email protected]
5 Replies
2808 Views
Last post July 02, 2006, 12:34:11 PM
by SUPERMAGOO
9 Replies
3880 Views
Last post March 19, 2009, 09:33:02 AM
by kato
31 Replies
20381 Views
Last post March 18, 2020, 12:27:37 PM
by EmRR