Sowter transformers for LA2A
« on: July 12, 2019, 09:49:52 AM »
Hi all,

Anyone had any experience comparing the Sowter 1010 and 1290 output transformers that both can be used in an LA2A build? I know that the 1010 is larger and has more nickel in it whereas the 1290 is slightly smaller and has more silicon iron. Any major sonic difference?

Thanks.

Andrew


ron_swanson

Re: Sowter transformers for LA2A
« Reply #1 on: July 12, 2019, 02:18:04 PM »
Hi all,

Anyone had any experience comparing the Sowter 1010 and 1290 output transformers that both can be used in an LA2A build? I know that the 1010 is larger and has more nickel in it whereas the 1290 is slightly smaller and has more silicon iron. Any major sonic difference?

Thanks.

Andrew

Andrew,

Sorry, I can't answer your question directly, but I recently finished a Silent Arts Dual LA2A using Sowter 8940 & 4383 trannies.  The unit sounds fantastic!

You might try asking Sowter directly.  They have been very helpful sorting these kinds of questions out for me in the past.

Short of this, hopefully others on this board will have deeper information to share.


Best, Greg

Re: Sowter transformers for LA2A
« Reply #2 on: July 12, 2019, 09:54:18 PM »
Thanks for the response, Greg. It seems that the output transformer you used is similar to the 1010, if not the same.

This is how they compare (taken from Sowter):

The 1010 - Ratio 5:1. 15k/600 ohms output transformer for driving balanced line from ac coupled cathode follower or SRPP circuit. Total dc resistance ref secondary 30 ohms. Max output level +30 dBu. 50% Mumetal core for exceptional bandwidth and dynamic range. Similar to UTC A24 and Triad HS-50 (in overall 5:1 configuration) but with improved bandwidth.

The 1290 - Ratio 5:1. 15k/600 ohms  30% Mumetal core for exceptional bandwidth and dynamic range. Similar to UTC A24 and Triad HS-50 (in overall 5:1 configuration) but with improved bandwidth. Suitable for Drip Electronics Opto 4 and 5 PCB. Also suitable for UE-100 Output.  This transformer is very similar to type 1010 and is essentially a size and cost reduced version achieved by using a smaller lamination size and a smaller proportion of Mumetal laminations. The can size is also smaller and less expensive. The performance is unaffected except at very high level low frequencies where the THD measures somewhat higher.

johnheath

Re: Sowter transformers for LA2A
« Reply #3 on: August 05, 2019, 09:34:47 AM »
Hi...

I have used both the 1010 and the 1290 OT for several LA2A builds.

The one I am using now is the 1290 since I found it easier to mount on the outside of the chassis.

In the beginning I had some troubles with the original layout of components in a LA2A with the 1010 because it was picking up stray form PT. I did not experiment so much further with it at the time but went for the 1290 which in those cases solved the problem. Nowadays I have come up with an another layouts of components that "allows" me to use the 1010.

The sound doesn't really differ anything noticeable at all.

Best regards

// John
Nothing is impossible - It just takes some more time


 

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