Post by sadface on Feb 2, 2021 20:13:23 GMT 12
G'day Colin, Fixed. I thought I was making things more clear for myself by using V- and H- for power supply grounds and GND for signal grounds.
What do you think of my placement of the main chassis earth beside the output. It looks like area that is likely to be the lowest noise to me.
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Post by colinf on Feb 3, 2021 20:22:07 GMT 12
Looking good. You can distinguish the various ground sources from power supplies etc by calling them Gnd/H or Gnd/B+, or use an underscore instead of a forward slash, or even nothing, like GndH or GndB+. You can use 0V instead of Gnd as well. Like H_0V or B+_0V (notice the labels are back to front). So for several B+ supplies you could say B+A and B+A0V, for the next, B+B and B+B0V, etc. Earth at the input socket, good idea.
AMR-iFi R&D
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Post by sadface on Feb 3, 2021 20:31:17 GMT 12
Thanks for that,
I'm working on a relay input selector so as to avoid having to run shafts through the middle of tubes.
I have question regarding the type of rotary switch required.
I am looking at these guys, cheap ebay models appear to be available however I am inclined to pay for quality and buy ALPS
These are a shorting type. I can how see this might be problematic for an input selector: the new input relay being 'turned on' before the old input is 'turned off'.
Am I correct that I would be better to use a non shorting type switch?
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Post by RdM on Feb 3, 2021 20:52:55 GMT 12
I hadn't heard the term "shorting type" before, but reading on, aren't you just writing about what I in the old days might have called either a "make before break" or in this case, wanted "break before make" type of switch? Contacts.
Break the old connection before arriving at the new connection.
I've been inspecting with a view to using a 4 pole 4 way wafer switch recently, making sure that it truly is break before make, else disaster.
Regards!
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Post by Owen Y on Feb 3, 2021 22:46:27 GMT 12
You’d be switching the 5v or whatever to the relays, but I think I’d agree, you’d want non-shorting (break before make). PS. I used relays like that on my first preamp build but FWIW, I found that relays robbed the sound noticeably of ‘dynamics’ - compared with a cheap Lorlin silver contact rotary switch. (Relays used were Omron small signal type, G5V-2 IIRC.)
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Post by sadface on Feb 4, 2021 7:29:03 GMT 12
Thanks guys,
Break before Make etc would have been the term most common to me however on the Alps data sheets they seem to only refer to shorting or no shorting types.
Back to the drawing board it seems.
Owen, I recall your experience with relays from another thread. It does float around in the back of my head. On the other hand from looking around in commercial gear it seems as though relays are the industry norm.
It might well be that I have to go back to a plain switch in the longer run but I'm going to run this experiment as it will make the layout much simpler with one less shaft.
I am also considering trying a relay stepped attenuator for the volume control for the same reason.
Rdm, if you find an appropriate switch, please let me know as it seems as though we are looking for the same thing. I don't need 4 poles, only 1 is needed but it seems like a 3 or 4 pole is the easiest way to get a rotary switch with 4 positions.
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Post by sadface on Feb 4, 2021 7:32:53 GMT 12
Also one of my concerns is the feel of the switch.
The Lorlin switches have a cheap plasticy feel to their action.
I’m trying to find switches with more a nice solid metallic snap.
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Post by Owen Y on Feb 4, 2021 10:29:01 GMT 12
Lorlin switches - yes agreed, the plastic-cased ones I used do not feel great. However, often the size/mass of the knob has a great effect on 'feel'. Relays - other factors could be -(i) my implementation, the wire routing of the signal through a separate relay board (ii) the type of relay used, I just chose these as 'small signal relays'. I found my relay bd from yrs ago -
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Post by sadface on Feb 4, 2021 19:57:01 GMT 12
Pretty tidy for perf board work if I do say so myself.
I had what could be a good work around on the drive back from Hamilton today.
I could cobble together something like a transistor delay circuit in series with each relay coil for something like a 2second delay. I would have to duplicate it for each relay but I do somewhat like the idea of having a delay between sources.
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Post by colinf on Feb 4, 2021 20:04:01 GMT 12
I personally don’t like a lot of delay when changing inputs - 1sec max. I have an amp here that delays by less than half a second, I like that.
AMR-iFi R&D
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Post by RdM on Feb 4, 2021 20:11:37 GMT 12
Thanks guys, Break before Make etc would have been the term most common to me however on the Alps data sheets they seem to only refer to shorting or no shorting types. Rdm, if you find an appropriate switch, please let me know as it seems as though we are looking for the same thing. I don't need 4 poles, only 1 is needed but it seems like a 3 or 4 pole is the easiest way to get a rotary switch with 4 positions.
I have several of the 4-pole 4-way wafer switches mentioned NOS in sealed plastic packaging, left to me many years ago by a friend emigrating.
I'll happily send one for postage, likely a $3.50 pre-paid bag nationwide. PM me.
I'll take a pic or two tomorrow (cooking dinner right now;-)
Edit: in individual open ended small plastic bags, but still NOS. And just a few, 3-4 left. Happy to spare one.
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Post by RdM on Feb 5, 2021 19:02:37 GMT 12
You mentioned " Also one of my concerns is the feel of the switch.
The Lorlin switches have a cheap plasticy feel to their action.
I’m trying to find switches with more a nice solid metallic snap. "These certainly fit that bill. Very difficult to turn the shaft alone by fingers. In fact I just put minor pressure marks on the shaft of one using flat pliers... A hefty spring and ball arrangement into detents in a disc. Some tags have been bent down, perhaps tumbled in storage. But they're all NOS, have never been soldered to. The contact tracks seem to have been coated with a protective film, yellowish, not sure what it is. But it is easily cleaned off with isopropyl alcohol and a cotton swab. The one on the left is as is: And swapping them, here's the other after an easy wipe cleaning and straightening tags (left a few marks, crimps). Obviously a quality product from yesteryear! I see also on TM this, looks the same switch as your earlier RS link, but with a worked out PCB. www.trademe.co.nz/Browse/Listing.aspx?id=2962919158Apart from the price difference, an interesting idea to switch led indicators with unused poles. I find in storage I have 6-8 of these, a couple have some corrosion on metal surface, the rest are fine. I want to keep some for my own projects, looking at prices I should, else put some up on TM. I'm still very happy to donate one to your Aikido project ... if you think it will be of use? I've followed tubecad for years, have saved many 6SN7s, intended building one day, thought I might have to do it with tag strip or turret board, pcb beyond me, or not in my experience, so have followed this thread with interest. Thanks!
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Post by sadface on Feb 6, 2021 10:48:55 GMT 12
G'day Rdm, Using the extra pole to switch LEDS is exactly one of the options I was planning to allow for with this relay selector board. I'm in the middle of designing a board to mount a pcb mount switch like the alps I linked with a set of indicator LEDS for each source in addition to the LEDS on the relay board. This version would use an 10 way IDC ribbon cable so the front panel leds are on separate lines to the relays they indicate. One amp that is in the works is a small integrated amp for the bedroom and SWMBO doesn't want LEDS so that nice hefty looking switch of yours would be perfect. If you are interested in any of these boards it is very cheap to add extras. 5 boards with ENIG finish is about $30, it goes up to something like $35 to increase that to 10, interestingly 15 goes up to $45. I intend to clone the high voltage regulator boards from Linear Audio since it is a open source design and Jan Didden who designed it doesnt intend to offer any more boards. I am sure I will want some extras in the future. It might be worth it simply to have black boards that match all the rest of the black boards...
I end up designing so many boards for so many contingencies as I can see myself building so many different amps over the next couple of decades.
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Post by RdM on Feb 7, 2021 18:50:17 GMT 12
G'day Rdm, Using the extra pole to switch LEDS is exactly one of the options I was planning to allow for with this relay selector board. I'm in the middle of designing a board to mount a pcb mount switch like the alps I linked with a set of indicator LEDS for each source in addition to the LEDS on the relay board. This version would use an 10 way IDC ribbon cable so the front panel leds are on separate lines to the relays they indicate. One amp that is in the works is a small integrated amp for the bedroom and SWMBO doesn't want LEDS so that nice hefty looking switch of yours would be perfect.
This switch is 4 way 4 pole - so you could switch LEDs as well with it. That is, there are 4 sets of switches on the wafers, each with an output switchable between 4 inputs, so 5 contacts x 4.
I thought you wanted one with a hefty click action for your own amp? And to switch LEDs there? Why waste it where LEDs are not wanted? (Or did you mean that that would be the softer plastic one to hers, the solid metal one to yours? ;- )
Maybe your SO wouldn't mind a softer touch on her volume control. Would the softer action plastic one feel alright? Then use this on your own one?.
Another thing that comes to mind;- I've always liked amplifiers that have a separate Record Out switch as well as a Source switch. Ideally buffered, so that the source input isn't loaded down too much with the extra input/output, many aren't, but some are I think. A high impedance in low impedance out buffer I guess. Would it be phase inverting? Or can it be satisfactory directly connected after all?
Either way, a second switch is needed, if that facility is wanted. Listen to one thing while recording another. Or feeding the other elsewhere. Not sure how you'd integrate that with relays source selection though. Well sample straight from inputs or via a buffer I guess.
~ RdM
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Post by sadface on Feb 13, 2021 15:10:49 GMT 12
Boards are on order.
I decided against an ENIG finish, I will just stick to HASL.
It seems as though ENIG is mainly to assist with SMD soldering and since this is all through hole no need to pay 6x the price.....
Unfortunately, the Chinese new year is going on right now so it seems I will have to wait an extra week or so for manufacturing.
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Post by sadface on Feb 23, 2021 17:36:33 GMT 12
Fresh Boards arrived today.
The tube sockets now fit!
Here's a mockup sans resistors and I/O connections.
Now that I know the sockets fit, I am tempted to order another set of boards with the more expensive ENIG finish with my next pcb order
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Post by RdM on Feb 24, 2021 19:24:36 GMT 12
Boards are on order. I decided against an ENIG finish, I will just stick to HASL. It seems as though ENIG is mainly to assist with SMD soldering and since this is all through hole no need to pay 6x the price.....
I eventually had to look these acronyms up...
Perhaps a couple of useful links, with pros and cons?
I feel slightly wiser! ;-)
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Post by sadface on Feb 24, 2021 20:17:22 GMT 12
Thanks for those links.
I hadn't heard about the black back syndrome.
I think I will skip the ENIG and stick with good old lead HASL.
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Post by RdM on Feb 24, 2021 20:25:23 GMT 12
Glad to hear it!
Will enjoy reading of progress.
I'm not up to or into 'lead-free' either.
Shouldn't be necessary for a valve circuit with discrete components, surely...
I noticed the military were exempt from mandatory lead-free when it came in, a diktat by the EU?
Thanks! ;-)
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Post by sadface on Mar 23, 2021 20:41:04 GMT 12
G'day Guys,
I'm waiting for some 10R resistors to arrive from Mouser for my gainclone build. It could be a week or 2. Mouser took a full week to ship my last order a couple of weeks back. One can only assume covid....
So I've pulled the Aikido boards back out for some work.
All the resistors are now soldered.
Caps, headers and fastons to come. Fastons are also in the mouser order so I probably can't do much more before the order arrives.
It might be time to start on the PSU boards instead.....
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Post by colinf on Mar 24, 2021 20:24:25 GMT 12
Try RS, I think they have a warehouse in Auckland. I think the military know tin whiskers can grow on lead-free-soldered devices. Leaded solder doesn’t do that.
AMR-iFi R&D
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Post by Owen Y on Mar 24, 2021 21:23:42 GMT 12
Yes I use RS first port of call if I can now, free delivery, next day usually.
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Post by colinf on Mar 25, 2021 19:38:49 GMT 12
Example of a tin whisker. They affected early Ge transistors which would short circuit internally after a long time.
AMR-iFi R&D
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Post by RdM on Mar 25, 2021 21:27:24 GMT 12
I think the military know tin whiskers can grow on lead-free-soldered devices. Leaded solder doesn’t do that.
And then, slightly OT, off topic, there are also zinc whispers.
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Post by RdM on Mar 25, 2021 21:40:13 GMT 12
Fastons are also in the mouser order
I guess it's like tomayto and tomahto, but by "Fastons" do you mean some sort of metal standoff?
I needed just 2 M3 threaded standoffs for the temporary individual pair bias adjustment tagboard for the Wurlitzer amp recently, to hold up a DIN 8-way socket to connect via extension data cable a switchbox with a pair of meters, and in a hurry, held my nose to pay $7.90 for a pack of 8:
Regards!
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Post by sadface on Mar 26, 2021 8:02:40 GMT 12
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Post by sadface on Apr 18, 2021 21:27:32 GMT 12
G'day Chaps,
I decided to take a wee break from my gainclone project this afternoon so I did some more work on the Aikido.
The signal stages are done.
I'm glad I used a 105degree cap for the heater decoupling as it came out a bit closer that I had planned. I obviously didn't account for this when I made the tube socket footprint larger.
And with some cosmetic bottles!
All that remains is 5 power supplies, an input selector board and a chassis.....
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New Member
Post by avagreen on Nov 16, 2022 12:44:10 GMT 12
Dear Sadface Have you got any PCB,s for sale. Thx. Peter. (peter.gay@gmail.com)
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