Neumann W492 equalizer DIY project (PCB docs added)

[Rocinante]

So as far as the toggle switches go its a 5a spdt toggle that has to be on-non-on?  Does it have to be 5a?  Does it have to be on-non-on or can it be on-off-on?
C and K aren't cheap so I am just checking out my alternatives.

 

[horvitz]

I know that a whole bunch of you are waiting for me to get the BI 10K lin pots back in stock.  It is still going to be quite a while.  I thought I'd point out though that Digi-Key has the exact same part in stock.  Their part number is 987-1665-ND.  You could buy six of those and two of the 2x10K pots from me and that would give you a complete kit.  A little more money, but no waiting.

Brian

 

[Greg S.]

Thx Brian,

Greg

 

[Rocinante]

After some research (yeah a total of 20 minutes and sorry for wasting space) I have come to the startling and incredibly remarkable conclusion that on non on is the same damn thing as on off on.  So I guess companies just word it differently? I'm still very green. So pretty much just any ol sub-miniture spdt will do.

 

[kante1603]

Hello,

any spst will work.Look at the schemo or just at the pcb,only two points to solder.
If you have a toggle switch with an "on,off or anything else" in the middle then there's one position too much,not useful and also not used.
Just get a standard spst or spdt (one outer pin not used),so two positions for toggling,done.
Don't buy the cheapest types,they should work for some years,no? ;D
Also remember they will carry your audio.Well- known brands are the way to go.

Best regards,

Udo.

 

[Rocinante]

Thanks Udo. That helped clear a few things up for me actually. Overthinking and obsessing. I'm cursed.
Cheers

 

[kante1603]

You're welcome.

I have also seen your previous posts.
About current,no,5 Ampere are not needed,hahaha.....it is just that most toggle switches are capable to handle "high" currents.
It doesn't hurt.
In my 8-ch. version I have Miyama toggles that can handle 3A.......
Btw.,given current values are always different for dc than ac by nature.
As said all of them will work because current doesn't matter here.
"None" means that there is no middle position,so it is not the same as "off"!
You can see this clearly at the c&k data sheets when you do a search at mouser.
Compare a "none"-type for position 2 (middle) to the connected terminals,it says "N/A".
Here's a sheet from c&k,look at page 2 and you will see what I mean:
http://www.ck-components.com/14430/7000toggle_19jan12.pdf/
A lot of switches on the mouser page are indicated as "(on)" or "(off)" in several positions.
The brackets mean they act momentary,not latching/permanent.

Have fun,

Udo.

 

[Rocinante]

Ha. Again Udo thanks for clarifying these switches even further.  Yep I still got lots to learn. I had actually read the 7101 specs and tried to compare them to other switches but I guess the differences alluded me and eventually thought the "non-off" was just semantics.  And was wrong. I had tried searching via Google variations of "spdt on non or off on" but to no real avail. I got it now thanks.  I was planning on building a monitor controller in the near future, imitating other people's projects and I'm sure this will all become useful as well then.

Cheers

 

[sr1200]

I have a real strange one for this project... I have a PS with a +15v reg and -15v regulator (not a universal adjustable type which i probably should have gotten).  but when I turn the unit on, i get nothing (no audio through)  if i turn it off, and immediately back on again, it works fine.    I did notice that on that initial power up, when i turned it OFF, for a split second there was audio as the unit powered down (literally a split second).  Any thoughts on this?

 

[Gustav]

I have a real strange one for this project... I have a PS with a +15v reg and -15v regulator (not a universal adjustable type which i probably should have gotten).

Should make no difference.

but when I turn the unit on, i get nothing (no audio through)  if i turn it off, and immediately back on again, it works fine.    I did notice that on that initial power up, when i turned it OFF, for a split second there was audio as the unit powered down (literally a split second).  Any thoughts on this?

Sounds really strange. Are you seeing your supply voltages on the board?

Gustav

 

[sr1200]

Voltages are good on the board. On both power ons.

 

[Gustav]

Voltages are good on the board. On both power ons.

Did you connect the switches?

Gustav

 

[sr1200]

Yes, unit works perfectly after the second power on.  Makes NO sense to me at all. 

 

[kante1603]

Yes, unit works perfectly after the second power on.  Makes NO sense to me at all.

Hello,

so you mean it behaves correct after every second power up?
This would lead me to look for a faulty capacitor because it seems to be time- dependent.
If it is more a random thing then I'd still look for the regs if they are 7815 & 7915 types because some of them are known to latch up from time to time,especiallythe cheap ones.
Is it a stereo unit sharing one psu?If so try to connect/power them as single units,one after the other to see if the issue remains the same.This way you could see if it is psu or eq- related.

Just my thoughts,

Udo.

 

[sr1200]

Thanks udo. I think im going to swap out the big caps in the ps and the VRs.  Just really strange that the voltages are good on both power attempts but just fail the first time. The cap thing makes some sense, perhaps the chips dont like that

 

[kante1603]

Yes,i think that's the way to go.As it is time-depndent it might be a lythic or so doesn't charge enough when powered the first time.
Do you have 7815 & 7915 in your psu?
Personally I prefer other types,years back I had several latchup issues,especially with the negative ones.The cheap ones of course.It became a bit better when I bought more expensive types but was never really satisfied.
All gone when I went the 317/337 etc. route.

Cheers,

Udo.

 

[sr1200]

Yes i have the 7800's in there   Perhaps i should just grab one of Ptowns universal PS's and call it a day lol.

 

[kante1603]

Yes i have the 7800's in there   Perhaps i should just grab one of Ptowns universal PS's and call it a day lol.

Sounds like a plan.I have Joe's (JLM) AC/DC and Powerstations in most of my  non-51x/500 builds.

 

[sr1200]

I've used joes stuff on all my neve builds as well as a few others.  Good stuff, just takes a long time to get in from AU.  Whistlerock makes a nice one as well... just dont need the 48v rail on any of em.

 

[kante1603]

I've used joes stuff on all my neve builds as well as a few others.  Good stuff, just takes a long time to get in from AU.  Whistlerock makes a nice one as well... just dont need the 48v rail on any of em.

Same here,that's why I once ordered a stock of them,just the pcbs.Parts are standard stuff and you can leave the 48v parts out (or modify to anpther voltage to drive leds and relais).

Best,

Udo.