Bottlehead Forum
General Category => Technical topics => Topic started by: dmannnnn on January 08, 2010, 08:13:22 PM
-
They arrived today. A pair of surplus 35 position rotary switches, shorting style, unused. These look like they came off a control panel from a Siberian Nuclear power plant. Not the smoothest mechanism, but not too bad either. They are 3.5" a side and 3" deep. I will report back on them once I can get them loaded with resistors. It might be awhile though. If they can hold the contact well while switching they should work out pretty good.
Price on these is $34/pair shipped. I was thinking of a passive preamp in a bottlehead size chassis.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fimg39.imageshack.us%2Fimg39%2F8502%2Fpairz.jpg&hash=d85d13767e21f475b9818ce13b91db3caa6fd4c2)
Close up of contact mechanism
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fimg33.imageshack.us%2Fimg33%2F8420%2Fp1010007ym.jpg&hash=528639d02ca7e1118d9235c43d7152334e0e20a1)
http://cgi.ebay.com/Powerful-rotary-sliding-switch-35-steps-2-discs-2-PCS_W0QQitemZ250453363226QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a502f0a1a (http://cgi.ebay.com/Powerful-rotary-sliding-switch-35-steps-2-discs-2-PCS_W0QQitemZ250453363226QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a502f0a1a)
-
Booger! Those are industrial all right. They look like the stuff in the first mill I worked in. All the machinery had been built in 1942, built to last a hundred years. Serious stuf there! The controls were mounted on 2" thick slate panels.
Do you mean make before break when you said shorting? I'm interested in a pair.
-
Now those are some beefy rotary switches. You could use non inductive wirewounds to populate that thing.
-
Yes they are make before break. You can see the wiper spanning both contacts while switching. I tried to test them with the DMM and it seems to be okay. I won't know if they switch without noise until I get a signal going through them.
-
I don't care if I don't need them. They look so cool I'll have to order a pair.
-
Just pulled the trigger. Now I gotta figure out how to calculate all the resistors to populate them with. Most of the online calculators I've seen are for 24 step attenuators.
-
Post a link if you find a good calculator.
-
I wonder what these were initially used for? We will probably all end up on some sort of watchlist for buying Russian reactor parts or the like.
-
VoltSedond's Attenuator page has a calculator for resistor values. It has a tab on the excel spreadsheet for different kinds of attenuators. The advantage of the S5 is it only has 2 resistors in the audio path at a time. It takes the number of steps and one more resistor.
http://www.siteswithstyle.com/VoltSecond/12_posistion_shunt/12_Position_Pure_Shunt.html
It is the Zip file in magenta about 1/2 way down the page.
-
They just arrived today. These things are MASSIVE! I was planning on putting them in a 2u chassis but it's gonna hafta be a 3u.
-
Mudhiker,
I have been watching some just because I want to do this when I get my next temp job. I had imagined they were large but I have no idea how large.
Can you post a picture showing one next to a quarter? A Bottlehead product?
(changed my avatar since everybody in the thread has his dog)
-
Has anyone populated one of these monsters yet? They look big enough to use tantalum resistors in them.
-
I haven't touched them yet. In the middle of a foreclosure. :-( Probably won't be til later this year unless I get a wild hair.
-
VoltSedond's Attenuator page has a calculator for resistor values. It has a tab on the excel spreadsheet for different kinds of attenuators. The advantage of the S5 is it only has 2 resistors in the audio path at a time, but takes twice as many resistors..
http://www.siteswithstyle.com/VoltSecond/12_posistion_shunt/12_Position_Pure_Shunt.html
It is the Zip file in magenta about 1/2 way down the page.
Actually, the S5 configuration only adds one resistor to a standard stepped attenuator. It uses a single resistor for each step with an additional fixed input resistor. These can be made with a single pole (layer) switch. The 'ladder style' configuration switches the input resistor and uses 2 resistors in each step. This requires a 2 pole switch.
-
Yup, I wasn't thinking well.
-
Has anyone populated one of these monsters yet? They look big enough to use tantalum resistors in them.
Not yet. They are sitting here on my desk in the pile. Will update when I do get to them...
-
Mudhiker, You and I are the kings of procrastination. Don't feel bad, we have company. They just don't admit it.
-
Mudhiker, You and I are the kings of procrastination. Don't feel bad, we have company. They just don't admit it.
I resemble that remark.
Seriously, I will get to them sometime. I just finished a refurb on the old Marantz HD770's. So that leaves a magnepan crossover upgrade, Miracord 50HII plinth build, Step-up transformer build..... I will have them done by late 2011, promise.
-
...I completely forgot about the pair of Knight 615HC triaxial (rebadged Electrovoice 15trx) speakers I put in storage. Any suggestions for a sanely sized encosure for these would be appreciated.
-
The original links for these gems no longer works. They are available here: http://stores.ebay.com/Combat-Super-Store (http://stores.ebay.com/Combat-Super-Store). I bought a pair of the 2 disc versions (he's got 1 disc versions as well) as a future stepped attenuator for my FPiii. I imagine those won't fit in the chassis so they'll probably get their own box. I plan on putting in Goldpoints or some such thing when I build. As an aside, that store has a buttload of caps available. There was also a 330 ohm 1kw wirewound resistor in there, talk about huge.
Rich
-
Did you gents ever put these together? I'd love to see some pics. These resemble the Shallco steppers at quite a fraction of the price (http://www.shallco.com/rotary_switch.html)
-
These are USSR Military Surplus. I would guess that the quality control was high, as in, if you make a poor product for the Soviet Military you are .... gone.
The contacts are not going to be silver plated nickel which the Shallco most likely are.
-
Ha ha, going to give this old thread a bump because funnily enough I have only recently been looking at some of these very same switches and was pondering over a possible attenuator build myself, only last night talking with another bottleheader about seeing them listed on ebay and low and behold while googling for references and further details on the switches a google image search pulled this very topic page up lol.
Did anyone ever get round to putting one together as a attenuator? While its not going to be the most practical item to install. There is I think decent potential for interesting and relatively inexpensive passive pre project using what looks to be a bit of well made interesting cold war Russian surplus kit. I was thinking along the lines of stacking two pairs together to get four plates for a ladder type attenuator. Initially I was thinking of mounting in a wood block but having a better view of the switches that are posted here mounting them in a clear Acrylic tube might make for a bit of a fun conversation piece.
So here is the link to the switches I have pulled the trigger on also the seller has single and twin plate types available.
http://www.ebay.co.uk/itm/251494056457?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
-
Also noticed a attenuator build on Lencoheaven using the same switches
http://www.lencoheaven.net/forum/index.php?topic=10184.0
Right through with resistor calculations for a 100k pot.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.thomas-schick.com%2Fpic%2FIMAG0160.jpg&hash=b62b0d1518cff2b43f41f250b989e28de1767be7)
-
You'd really want to be sure that they are shorting switches, but the price to quality ratio seems to be really good.
-
The lenco site confirms they are make before break and this pic from the sellers listing gives a bit of a indication.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.ebayimg.com%2F00%2Fs%2FMTA2MVgxNjAw%2F%24%28KGrHqNHJ%210E8%2Bm%2B8QBMBPV0yfyZcw%7E%7E60_57.JPG&hash=6cf0c4f69da374a8aeda2e9344c3b6d99e76ea9f)