It's alive! hm, not quite, it's a TVC! - Danny T - Tube DIY Asylum

Tube DIY Asylum

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It's alive! hm, not quite, it's a TVC!

62.235.20.20

Some weeks ago I've finished building a transformer volume control based on the sowter 9395.
It's almost the same as the 9335 but with extra primary connections for +6db and +12db.
Now after two weeks of listening I am very satisfied with the result,
I didn't expect it to be such a major improvement compared to my previous passive preamp: a 6k dale resistor with a 10k DACT in shunt.
With the Sowter TVC the music is much more open, more extended lows and highs, seperation between instruments is much better, there's more low level detail.
I now detect backing vocals that I previously didn't hear, I hear multiple instruments instead of one. Every instrument, vocal has gotten his own space instead of drowning sometimes in each other. Also piano's sound more real.
It's like I've pushed on a big 3D button on my system, without using some special 3D spectacles ;)
For passives forget ladders or series, a TVC is the best you can make,
compared to a ladder or a series attenuator you get:
- complete galvanic seperation between the stages.
- a high input impendance and a very low output impendance.
- you don't throw the signal away to ground, you just change the ratio voltage/current.
Another option is the Stevens & Billington TX102, but I chose the Sowter 9395 because it has more attenuation levels down to -50db, all in 2db steps.
I've put the two transformers in a custom enclosure of 6.5"x6.5" I ordered from par-metal. They look great!
As rotary switch I use the Elma Audio Switch Series A 04A2A00 that is normally used as a series attenuator,
but you can also use it as a 24 position switch by using only the solder contacts of the inner circle.
I had read somewhere that the Elma 04-2130 or the 04-2133 that normally is used had some bouncing problems.
The only thing I had to do extra was to connect the grounds of both the output RCA jacks to each other otherwise I got hum with my monoblocks.
My system:
cd-player: NAD C541 (tweaked), soon to be replaced with DIY non oversampling DAC with tube output and CD-pro2 transport.
preamp: sowter TVC 9395
amps: DIY monoblocks PP KT88(triode) with LL1660 IT splitter and LL1623 OPT (Lundahl iron sounds great)
cables: alpha goertz MI2 speaker cables and Van den Hul D102 MkIII interconnects (DIY connectors bulk cable)
speakers: DIY big three-way MTM-W each with 4 visaton drivers and high quality crossover (all first order filters, 6db slopes sound much better than higher order filters)

http://www.sowter.co.uk/attens.htm (Open in New Window)

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Topic - It's alive! hm, not quite, it's a TVC! - Danny T 05:10:26 10/19/02 (14)

Re: It's alive! hm, not quite, it's a TVC! - Morse 12:43:00 10/19/02 (11)

Re: It's alive! hm, not quite, it's a TVC! - MikeWI 08:10:56 10/21/02 (0)

Re: It's alive! hm, not quite, it's a TVC! - Danny T 04:46:53 10/20/02 (3)

Re: It's alive! hm, not quite, it's a TVC! - Morse 08:24:08 10/20/02 (0)

Danny would have paid 17.5% VAT but ... - Brian C. 06:52:31 10/20/02 (1)

Re: Danny would have paid 17.5% VAT but ... - 45drive45 07:30:59 10/20/02 (0)

Ordering - 45drive45 19:42:32 10/19/02 (5)

Thanks 45drive45! - Morse 11:06:25 10/20/02 (4)

International ordering - Red Pill 19:51:19 10/20/02 (3)

Re: International ordering - Danny T 03:18:51 10/21/02 (0)

Re: International ordering - Morse 22:09:11 10/20/02 (0)

Thanks for the list nt. - C.Y 21:06:38 10/20/02 (0)

Re: It's alive! hm, not quite, it's a TVC! - 45drive45 09:52:07 10/19/02 (1)

More gain - Danny T 04:48:51 10/20/02 (0)

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