Relays for audio-suggest?

[Ricren]

Hi folks,

I'm in the process of building a preamplifier that needs clean audio switching.. That's a lot of relays, so I'm asking for suggestions about what kind /brand of relays would you recommend for audio.

thanks for any direcction,

Ric

[till]

I use takamisawa RY12W-K

[Ricren]

I read in an old post that Mr. Pass recommends Aromat relays, but I can not get them locally. I'll search for the Takamisawa part, thanks.

Ric

[Ricren]

Excuse my ignorance, I was reading relay specs and there are some terms that I'm not sure to understand :

1-DPDT
2-4PDT
3-Latching relay

Sprry for this basic question, but I need to learn about this,

cheers

Ric

[JordanG]

Originally posted by Ricren
1-DPDT
2-4PDT
3-Latching relay

I'll do my best with the switching terminology..

The first quantity is the pull, and it represents how many switch elements the device has.
The second quantity is throw, and it represents how many connection points the switch element has.

So for instance, lets take SPDT (single pull, double throw). There is one switch element that has two different positions inside of it. 4PDT would have 4 switch elements, and each switch would have two positions. If it were DPST (double pull, single throw), then it would have two switches, and each switch would only have one connetion point (so its either an open or a short).

A good visual of the DPDT (double pull, double throw) relay can be found on page two of the following PDF...
http://www.nec-tokin.net/now/english...lay_MR82_e.pdf
Notice that there are two "switches" inside of there. And when you apply a voltage over the coil, something like a magnetic field is created (I think..), which throws the switch. In general, I think that all the switches are thrown at the same time (they can't be thrown independently of one another).

Hope that helps. Not really sure about a latching relay. But my best guess? A latch is a storage element. So maybe you apply a pulse in order to switch the relay.

--Jordan

[psychokids]

Yep, latching relays have magnets inside so that when the relay is switched and power is removed, the contacts stay in the same position. Very useful in battery powered stuff. However, there are 2 types of latching relays, single coil and double coil. The single ones have just one element, and in order to switch the position, you have to reverse the polarity of the supply. Double coils are usually more conveniant to drive, and have 2 coils. One to switch to one side, and the other to switch it back. In most applications where there is an available power supply that is not battery driven, the circuitry needed to provide pulses makes normal relays much less of a hassle.

-Chris

[machinow]

Ricren [/i]
Hi, don't care about the pre-amp relays - almost no current flows through them, so they can not distort! No matter the manifacturer, only should work!!
In power amps u should take care of this, the THD of the relay may be 0.01% and more, but better if you include in the feedback path!
bye

[MRehorst]

The Aromat or NAIS labeled DS series relays are designed for switching small signals. The contacts are bifurcated (forked) and made of gold clad silver. They are designed for high reliability in telecomm switching (i.e. audio freqs). They come in latching and normal types. They are relatively cheap at $3-4 each.

Relays that are not designed for the purpose can exhibit all sorts of weirdness with small signals. Contact resistance changes each time the relay closes, corrosion occurs and can cause rectification and distortion.

If you want to switch small signals, use a relay designed for the purpose.

MR

[analog_sa]

machinow

relays at low levels may not generate measurable thd (but then what does?) but they affect the sound dramatically. As do any kind of switches. The question which relays deteriorate the sound quality the least is very relevant. Theses audutions are however time consuming and exhausting and i'm not too keen to do them. Been doing fine with no relays so far.

cheerio

peter

[guido]

Ric,

I am using SDS relays in my preamp (12V types). Have them for a while now, so i don't know if the type can still be purchased.

They work fine for me. Check www below for some info on the preamp.

Greetings,

Guido