EMI RS124
- Thread starter ed rees
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Jean Clochet
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I feel like a Boy Scout in the presence of Navy Seals. Suffice it to say that I have no further questions regarding R17. ;D
I know I promised to go away, but I'm strangely drawn to ask another stupid question (I've got a million of 'em!). This (again) is in reference to the RECOVERY switch circuitry.
1) Regarding the relay - aren't H.1 and H.2 redundant? It looks to me as if they could have used a simple SPDT relay instead.
2) Why, instead of using a 12-position rotary for the RECOVERY switch, didn't they just use a 6-position switch for the active positions, and a separate SPST switch for a "Master" HOLD switch (emulating the function of the relay)? This would not only have reduced wear and tear on the rotary switch, but would have actually given engineers the option to silently change recovery times before reactivating the compressor (assuming there would ever be a desire to do that).
Okay...I'm bracing myself for a smack-down. :-[
I know I promised to go away, but I'm strangely drawn to ask another stupid question (I've got a million of 'em!). This (again) is in reference to the RECOVERY switch circuitry.
1) Regarding the relay - aren't H.1 and H.2 redundant? It looks to me as if they could have used a simple SPDT relay instead.
2) Why, instead of using a 12-position rotary for the RECOVERY switch, didn't they just use a 6-position switch for the active positions, and a separate SPST switch for a "Master" HOLD switch (emulating the function of the relay)? This would not only have reduced wear and tear on the rotary switch, but would have actually given engineers the option to silently change recovery times before reactivating the compressor (assuming there would ever be a desire to do that).
Okay...I'm bracing myself for a smack-down. :-[
Jean Clochet
Well-known member
Post removed.
Jean Clochet
Well-known member
Post removed.
Hi Jean,
I wasn't talking about REPLACING the relay with a switch, I was talking about a separate HOLD switch that EMULATED the relay (just a way of describing how it would be wired). In other words, since the only thing all six HOLD positions do is short the rotary wiper to the junction at R12, why not just use one little make/break toggle or PB switch for this function? It just seems like a less cumbersome way to accomplish the same task to me (while leaving the relay in place for remote switching).
My other question regarding the relay referred to their use of a DPDT unit instead of a SPDT version. It reminds me of a miniature Rube Goldberg machine. What function does the H.1 half perform? Why not just run the connection through H.1 OR H.2?
Maybe I'm missing something.
I wasn't talking about REPLACING the relay with a switch, I was talking about a separate HOLD switch that EMULATED the relay (just a way of describing how it would be wired). In other words, since the only thing all six HOLD positions do is short the rotary wiper to the junction at R12, why not just use one little make/break toggle or PB switch for this function? It just seems like a less cumbersome way to accomplish the same task to me (while leaving the relay in place for remote switching).
My other question regarding the relay referred to their use of a DPDT unit instead of a SPDT version. It reminds me of a miniature Rube Goldberg machine. What function does the H.1 half perform? Why not just run the connection through H.1 OR H.2?
Maybe I'm missing something.
Jean Clochet
Well-known member
Post removed.
Jean,
You're right - what I meant to say was that the only thing all six HOLD positions do is CONNECT OR DISCONNECT the rotary wiper to/from the junction at R12. My mistake.
Yes, I'll probably build my unit differently. Initially it seems like a neat idea to duplicate an RS124 as accurately as possible, but when I see things in the design that are there "just because"...'Can't do it.
You're right - what I meant to say was that the only thing all six HOLD positions do is CONNECT OR DISCONNECT the rotary wiper to/from the junction at R12. My mistake.
Yes, I'll probably build my unit differently. Initially it seems like a neat idea to duplicate an RS124 as accurately as possible, but when I see things in the design that are there "just because"...'Can't do it.
Jean Clochet
Well-known member
Post removed.
A new mystery: R12
When Altec added a RELEASE circuit to the 436C (a pot and resistor), they placed it between the plates of the 6AL5 and R12 (33K). However, when EMI added their RECOVERY circuit, they placed it on the other side of R12.
Why might they have made this decision?
I gotsta' know!
When Altec added a RELEASE circuit to the 436C (a pot and resistor), they placed it between the plates of the 6AL5 and R12 (33K). However, when EMI added their RECOVERY circuit, they placed it on the other side of R12.
Why might they have made this decision?
I gotsta' know!
Jean Clochet
Well-known member
Post removed.
Jean Clochet
Well-known member
Post removed.
Biasrocks
Well-known member
EarBud said:
My guess is because it sounded and performed better.
Regards,
Mark
Hi Mark,
Sure, but what made them suspect that it would sound and perform better - enough to actually try that particular change?
I mean, I don't think the engineer said, "You know, we could start changing component and lead destinations at random just to see if things sound and perform better...why don't we start with R12?".
Sure, but what made them suspect that it would sound and perform better - enough to actually try that particular change?
I mean, I don't think the engineer said, "You know, we could start changing component and lead destinations at random just to see if things sound and perform better...why don't we start with R12?".
Jean Clochet
Well-known member
Post removed.
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