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I am currently in the process of building passive preamplifier using Sowter 9335 transfomers. I was looking for high quality rotary switch and my search revealed products from ELMA, SHALLCO and COLE.ELMA switches are OK but they have max 24 positions and my transformers are having 26 outputs. I know that I can leave some unconnected but...
SHALLCO products are very good. Solid silver contacts, military specs etc... About 100 USD for 2 deck, 26 positions, single pole, shorting switch.
Then I called people at COLE. Their open frame switches are similar to SHALLCO's but they are very expensive. Same functionality as above would cost about 360 USD plus 500 USD setup fee. (They charge setup fee for small orders.) On the other side, their customer list includes institutions like SONY Musical, Lawrence Livermore National Laboratory, various military and aerospace companies. Their switches can cost many thousands of dollars depending on setup.
Links:
- ELMA
- SHALLCO
- COLE
Probably I am going to get SHALLCO switch. Any other suggestions?
Follow Ups:
I used a Blore Edwards switch for my S&B TVC (www.blore-edwards.co.uk).It seems quite good but not as good as the Shallco. Mine is the cheaper type SZ rather than their type 72 which does seems very similar to the Shallco. I've use dthe Emlna's in the past and they are good but not as good as the Blore Edwards.
If you are based in the USA then I'd get a Shallco unless you can find an old NOS one.
Regards,
Jonathan
I am in the process of ordering the 9335 attenuators and sent an email to Mr. Sowter asking his opinion on a switch. He didn't have one except he said it should be a non-shorting switch. Don't know the reason, but I noticed that the switches you were looking at were shorting types. You may want to check with Sowter first just to make sure before you buy. Once you decide on the switch can you post the model number for reference.Thanks,
David G.
Hi,With ALL DUE RESPECT - Mr Brian Sowter knows not what he talks about. He is the guy who originally after a long process of organising a > 20 pair group order for a specification matching the over a year later released and now discontinued 9300 decided to change the spec to a transformer requiring a swiched secondary AND primary plus some other chages I was very unhappy about.
Basically, in more cases than not using a non shortening switch will cause much more substantial switching transients than using a shortening one. And IF you take my advise, get them to make you a 9300, NOT a 9335 and pay the extra cost or just get the S&B TX102 which is notably beyond what I originally asked B. Sowter to make.
BTW, the best switches I know are NOS GEC-Pleesy units that are in essence identical to the units nowadays available from Electroswitch. Buying them NOS often results in a 1000% price reduction on current list, if you can find them.
Later T
Dear Thorsten,
I am interested in the transformer attenuator for my linestage. Would you please explain and describe the differences between S&B TX102 and Sowter 9335. Also, how many positions or steps the S&B TX102 has? And what type of the switch require to use with the S&B TX102 (non-shorting or shorting?)Thanks in advance!!
PPT
When giving recomendations and preferences on certain techniques
and products, I think we should keep a good balance between theoritical knowledge and real aural experience.Mr. Thorsten have you ever heard the 9335 by yourself?Respectfully
Benoit
Hi,No, I have not heard the 9335, but I'm quite familiar with the older now discontinued 9300. The 9300 IMHO is the superior device to start with, as it offered superior winding geometry and bandwidth.
I'll comment on direct comparisons between the 9300 and the TX102 as soon as I have gotten hold of my pair TX102's.
Later T
"BTW, the best switches I know are NOS GEC-Pleesy units that are in essence identical to the units nowadays available from Electroswitch. Buying them NOS often results in a 1000% price reduction on current list, if you can find them."
Where I can buy them?
Giorgio
Hi,Switches like that turn up at my local Vintage Audio and HAM (Amateur radio) Fairs.
Later T
I already made first prototype using 9335s and all I can say is that result is outstanding. It is even better than I expected.I am running balanced signal from CEC TL-5100Z CD player into the pair of Mackie HR824 monitors through the 9335 transformers. Currently there is no switch employed but set of crocodile clips keeps everything connected.
I have used passive preamplifiers before but this is completely different story. There is no electronic glare anymore. Stereo space is better defined and you can hear every single instrument separately with no effort, even in very complex passages.
Bass is better defined and deeper. It has more edge.
But most striking difference is dynamics at low listening levels. That I never heard before, on any preamplifier. Simply, you can hear everything, doesn't matter how low is the volume.
Thorsten,
Since I haven't seen a diagram of the two transformers (S&B and Sowter), I am not sure I understand the differances. From your previous post, you stated that the Sowter requires the switch on the secondary of the transformer. So, is the differance that the S&B has the switch on the primary. Please cut me some slack on this as I am trying to understand.
Thanks,
David G.
Hi,Both Transformers use a multitapped secondary. However, it took Sowter about a Year after my original abotrted group order to make such a device, the one they originally wanted to make (nd which non of use wanted to buy) switched both primary and secondary. This (luckely) never realised.
The main differences between the Sowter and S&B are in the winding geometry and core size. The S&B unit is fully symetrically wound (thus allowing balanced to unbalanced conversion and visa versa) with a larger core (thus can handle more level for the same distortion or has lower distortion for a given level and it also appears (have not been able to get my hands on a pair) to have a wider bandwidth.
What I can say, being familiar with the Studio Transformers from Sowter and having now tried several units from S&B at different preice levels and for different applications, IMHO the units made by S&B are by far better sounding. They all come at least pretty close or in case of the TX10.. series by far exceed various antique units taht I have been using so far.
Ciao T
T,
Where, when, how? on this transformer? Who makes it?
Dan
http://www.stevens-billington.co.uk/pagehifi.htm
Now I know how to finance this hobby.
A 1000% Difference in price?The old GEC/Pleesy units sell usually around 10UK Pound or less for a 2-Deck, 32 position version NOS. Buying the same unit from Electroswitch is a little more expensive....
And okay, it's not even quite 1000%, a set of switches fro the Toccata set me back 30 Pound for the lot, NOS. ELectroswitch quoted something near $ 1,000 for the same spec.... That's a 500% difference, not 1,000%.
But please keep paying retail and leve the old switches to me.... ;-)
Ciao T
SEIDEN SD-45/56/62/75 SG Series
Features
- Dimention : 45 to 75mm diameter type
- Durability : 50000 times
- Step : SD-45 enable to change 2 to 28 step.
- SD-56 enable change 2 to 34 step.
- SD-62 enable change 2 to 46 step.
- SD-75 enable change 2 to 58 step.
- 3 point support
- Made in Japan
copper construction, weight approx 1.5kg for the SD-75 i think.
Regards
James
Hello,
Unless you have a really "big" resistor such as Vishay VTA series, then the Shallco is your only choice for building a resistive stepped attenuator.IMO, the Electroswitch is the best sounding attenuator switch I have came across. The drawback is that it has a limit steps (22 steps). Sometimes high price does not really make good sound.
Happy Holidays!!
PPT
Dear PPT,Where to buy the Electroswitch switch ?
Thanks a lot!Edwin
Dear Edwin,
The Electroswitch attenuator I have mentioned is called C7 Series Rotary Switches. This is the same attenuator switch use inside the Sonic Frontiers SFL-2. Since Sonic Frontiers use 1 C7 switch and wire in series for Balanced application, and supposed better to use 2 for L-pad. If your preamplifier circuitry is "Unbalanced", you need one C7 and wire in L-Pad (ladder). You can download the C7 technical information from the link at:http://www.electro-nc.com/cat_m.shtml
You might try the The Parts Connection, they use to sell the C7. If they sold out, then you have to buy direct from the manufacture, but slightly expensive.
Happy Holiday!!
PPT
Hi PPT,
I got my Electroswitches from Allied Electronic. They were cheap but the shipping costs to the Netherlands almost exceeded the price of the goods. I am very happy with these switches as the Elma's got totally rotten after six years of use.
I use the 47 position Shallco for volume in 1.5 dB steps as a shunt attenuator and the Electroswitch for balance a la Mark Levinson JC-2 and selector.
ELSO
Lordy, I thought the picture was of a Shallco! I've had good luck with Shallco and note the price breaks as if you buy four the fifth one is a free.....They take Visa/MC and quote six weeks for delivery and they normally show up in under a month....
I have no personal experience with these atennuators but you may wish to consider:
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