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OLDER DECWARE GEAR SUPPORT >> SE84A, SE84B, SE84C, SE84C+,SE84CKC >> SE84CS mono output transformer matching
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Message started by EdG on 06/13/10 at 18:28:46

Title: SE84CS mono output transformer matching
Post by EdG on 06/13/10 at 18:28:46

I'm the proud 'new' owner of SE84CS #152 & #260. They are operating as mono-blocks, and sound very good, but I'm not sure they are very well matched, and there is a phase 'oddness' to the sound, though it's more noticeable when warming up.
To match the levels, the older model has it's pot turned down to about 93% (measured resistance), but the older one still sounds more 'juicy' & the newer a little more flat.

I've checked voltages & components all look (& measure) to be the same & in good condition & swapped the valves several times with the same results. The only difference I've found is the output transformers. The older ones primaries measure 12H & the newer ones 22H. The corresponding numbers on them are EM0493 & EM0406.

Is it possible to buy a suitable pair of transformers to match the two amps? I have to say I'd prefer them to sound more like the older one, though if this isn't possible, having them both the same as the newer one would be ok.
Incidentally, I don't live in the U.S. so shipping back to base would be difficult (& costly!).

Title: Re: SE84CS mono output transformer matching
Post by dank on 06/14/10 at 01:11:43

I'm interested in the answer to this one too. My 3 year old Zkit1 has the EM0406 transformers and I'm wondering if there is a better one for my "hot rodded" zkit1. This transformer seems to work ok for 4 ohm or less loads, but at a 8 ohms the transformer seems to be the limiting factor in power delivered to the load. Something with a smaller turns ratio is what I would like to try.

Dan

Title: Re: SE84CS mono output transformer matching
Post by Steve Deckert on 06/14/10 at 16:16:04

The EM406 is the original transformer for the SE84C and SE84CS. It is set up to drive 4 ohm speakers. This transformer has a 9800 ohm primary.

The EM493 is also known as the "EX transformer" is custom installed when a customer is driving 8 or 16 ohm speakers. This transformer has a 3300 ohm primary.

Steve