A question for the panel.

I am thinking of building myself a preamp. And I think I would like to
use relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

--
Nick

In article , Nick Gorham
wrote:
A question for the panel.

I am thinking of building myself a preamp. And I think I would like to
use relay switching for the input selectors.

My experience with 'mechanical' relays is that they all give problems in
due course. Although perhaps not for a decade or more if chose and used
with care... and luck.

What recommendations do folks have about a good relay to use for this
application?

My recommendation would be to use either diode switching or electronic gate
switches. Far more reliable than mechanical types in my experience, and
easy to use.

If enthusiastic about valves, I suppose you could use a diode switching
arrangement base on diode valves. No idea if anyone has tried that. 8-]

What gets used in studio kit?

Dunno.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.audiomisc.co.uk/index.html
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html

"Nick Gorham" wrote in message
...
A question for the panel.

I am thinking of building myself a preamp. And I think I would like to use
relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

FETs.
Iain

"Iain Churches" wrote in message
ti.fi...

"Nick Gorham" wrote in message
...
A question for the panel.

I am thinking of building myself a preamp. And I think I would like to
use relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

FETs.
Iain




I agree, FET switching works fine on my preamp (ARC SP11), lot more
dependable than using relay switching.

Mike

"Nick Gorham" wrote in message
...

A question for the panel.

I am thinking of building myself a preamp. And I think I would like to use
relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

Reed relays are the modern relay of choice for low current/dry circuits.

What gets used in studio kit?

Depends on the application. One does not see a lot of relays used due to
cost. There's a lot of switches on the front panels of much audio production
gear, and some of them might be relays were it not for the cost.

On Wed, 17 Oct 2007 10:29:47 +0100, Nick Gorham
wrote:

A question for the panel.

I am thinking of building myself a preamp. And I think I would like to
use relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

If you really do want to use relays, Teledyne have DPDT items I have
used at over 1GHz in signal generators. They are ultra reliable too.

http://www.teledynerelays.com/electr...f300grf303.asp

d

--
Pearce Consulting
http://www.pearce.uk.com

Don Pearce wrote:
On Wed, 17 Oct 2007 10:29:47 +0100, Nick Gorham
wrote:


A question for the panel.

I am thinking of building myself a preamp. And I think I would like to
use relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?


If you really do want to use relays, Teledyne have DPDT items I have
used at over 1GHz in signal generators. They are ultra reliable too.

http://www.teledynerelays.com/electr...f300grf303.asp

d


Thanks for all the suggestions, I need to go and do some thinking now.

--
Nick

"Nick Gorham" wrote in message
...
A question for the panel.

I am thinking of building myself a preamp. And I think I would like to use
relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

--
Nick

A practise used in some professional kit is to use encapsulated FET switches
(CMOS 4016) types and locate them at a virtual earth point. This ensures
that in the 'On' mode, there is minimal voltage across them and hence
minimal distortion. It also has the advantage of being able to switch them
on and off using CMOS logic levels. (FETS usually require asymmetric
switching voltages on the gate)
A refinement on this is to use 2 CMOS switches per source at the virtual
earth driven in antiphase so that the input source voltage is shorted to
ground when required to be off. I would also suggest amplifying the inputs
to some internal working level before switching, so use a RIAA amp to get
the disc source up to (say) 500mV and then start switching: don't switch the
RIAA disc input source directly.

Mike

fredbloggstwo wrote:
"Nick Gorham" wrote in message
...

A question for the panel.

I am thinking of building myself a preamp. And I think I would like to use
relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

--
Nick


A practise used in some professional kit is to use encapsulated FET switches
(CMOS 4016) types and locate them at a virtual earth point. This ensures
that in the 'On' mode, there is minimal voltage across them and hence
minimal distortion. It also has the advantage of being able to switch them
on and off using CMOS logic levels. (FETS usually require asymmetric
switching voltages on the gate)
A refinement on this is to use 2 CMOS switches per source at the virtual
earth driven in antiphase so that the input source voltage is shorted to
ground when required to be off. I would also suggest amplifying the inputs
to some internal working level before switching, so use a RIAA amp to get
the disc source up to (say) 500mV and then start switching: don't switch the
RIAA disc input source directly.

Mike


Cheers, I wasn't considering switching at those low levels, purly line
level. I have such a virtual earth at the front of the buffer stage I
was intending to use.

--
Nick

Iain Churches wrote:

"Nick Gorham" wrote

A question for the panel.

I am thinking of building myself a preamp. And I think I would like to use
relay switching for the input selectors.

What recommendations do folks have about a good relay to use for this
application?

What gets used in studio kit?

FETs.

And relays. Sealed ones with gold plated contacts. Check out Panasonic's DS and
NF series.

Graham