Vintage-modern switch

Seeing several new units with vintage modern voicing switches.


Was wondering what it was all about till one manufacture mentioned that it switches capacitors, the vintage setting means your using tants modern setting has you using lyrics.

Hmmmmm. Thoughts or opinions?

pucho812 said:

Seeing several new units with vintage modern voicing switches.


Was wondering what it was all about till one manufacture mentioned that it switches capacitors, the vintage setting means your using tants modern setting has you using lyrics.

Hmmmmm. Thoughts or opinions?

Click to expand...

What kind of unit?

Back in the '80s I did a kit CX record playback decoder. This was a poorly received encode/decode vinyl noise reduction developed by CBS.

Long story short. when I designed the playback decoder, I studied the encoder schematic (designed by Urie) and noticed that they used a tantalum cap in the side chain attack/release circuit. So I used a tantalum too in my playback decoder. Tantalum caps are notorious for DA (dielectric absorption). This is a well known problem that prevents people from using tantalums in sample and hold circuits (among other reasons). Well I didn't want to make my decoder better than the encoder**, I just wanted to make it as close to the same as what was encoded onto the records as I could.

So yes there will be a subtle difference between tantalum and film caps used in att/release circuits. I suspect normal aluminum electrolytic caps are different too.  Note: I am not making any big claims about audibility of this, just that in theory there is a difference in attack/release circuits.

JR

** a funny anecdote, while studying the encode circuitry I noticed that the time constants in the pro-forma playback circuits published by CBS for licensees to use was not the same as the actual encoder time constants, and published standard.  I made mine accurate to the published time constant standard, and notified CBS of the discrepancy. Then I released my kit article to Popular Electronics to print. By chance a few weeks later at the AES show in NYC while talking to somebody in the Urie booth I mentioned this, and they told me that CBS had changed the time constant standard to agree with the mistake, because licensees had already made tens of thousands of consumer playback decoders with the erroneous time constant.  It's not hard to imagine that CX would fail. That gang could not shoot straight.  8) 

The unit was a mic pre. I have seen it before on other units and wonder if it's the same idea as in the mic pre I am referring to.

never mind... DA expresses far less in constant impedance termination with AC.

I have no idea what they are pimping.

JR