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Date: Sat, 25 Apr 2020 02:54:54 -0700
Subject: Re: [EE] Seeking audio relay advice
Thread-Topic: [EE] Seeking audio relay advice
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If you're willing to take a bit of a risk, it looks like there are a lot of
sellers which are selling lots of 10 of the original part number shipped to
the US for around $13 on aliexpress.   Or in singles for $1-2 each.
Whether they're new old stock, or removed from equipment, or counterfeit,
there is no real way to tell.   But for $10-20 I'd personally give it a
shot.

If you're wanting to try something else, the real question is what is the
failure mode on the relays.

If it's low signal audio, the failure mode most likely has to do with not
regularly exceeding the "minimum switching current" rating of the relay -
meaning that oxide has built up on the contacts and there isn't enough
current going through the relays to punch through it.   If this is the
case, then replacing with a reed relay makes some sense.   Personally, I
might be tempted in this case to give replacing the armature/contacts in
the existing relays with a pair of SPDT reed switches a go.   I saw David
VanHorn mentioned mercury wetted relays - that's another option if one can
find one.

One note on the above : sometimes you can rejuvenate a relay that has
oxidized like this by running a few dozen mA's through the contact and then
causing the coil to cycle.  But it won't be permanent, just like replacing
the relay with another 'too high current rated' relay won't be permanent.

On the other hand, if the failure has to do with switching the power that
runs the amplifier, then there is a good chance the failure has to do with
exceeding the switching current on those relays, even if it's a very brief
period.  In which case a higher current rated relay will be necessary.






On Fri, Apr 24, 2020 at 8:41 PM Bob Blick <bobblick@outlook.com> wrote:

> Backstory: ten years ago I was given a Phase Linear 3000 Series 2
> preamplifier. The friend who gave it to me said it had relay problems.
> Recently I acquired a matching power amplifier, and I'd like to get them
> both running, because they look awesome together.
>
> The preamp has no audio switches. All audio switching is done with 13
> relays, DPDT, 24VDC, in DIP package.  The relays it has were made by OMRO=
N,
> with clear plastic lids. Evidently there were a lot of problems, because =
I
> have a factory service bulletin that says to replace them with Aromat
> HB2E-DC24V relays, which are nitrogen filled and hermetically sealed.
> Unfortunately after Aromat was absorbed by Panasonic they were discontinu=
ed
> shortly afterward. And the pinout is not standard.
>
> Looking at various forums, evidently the Aromat/Panasonic relays were
> better, but not perfect either. There are people on eBay that have the
> Panasonic branded relays for sale. They appear to be new old stock, about
> $15 each.
>
> So my choice appears to be either put in $200 worth of NOS relays that ma=
y
> not be perfect, or make a bunch of adapter PC boards to adapt a different
> set of relays to fit.
>
> My question for y'all is this: Is there a 24VDC DPDT DIP relay that
> actually works well for audio? If so, it might be worth the trouble to
> adapt them to fit. Otherwise, I'll just bite the bullet and take the chan=
ce
> on some 20-year old new relays that might give me problems in just a few
> years(or immediately).
>
> Not interested in analog switches, I'd like this preamplifier to retain
> its original sonic character.
>
> Thanks in advance! Bob--
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>


--=20
- Forrest
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
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