[silent:arts]
Well-known member
they are
Sorry, must be that I missed that. Where is the sweep measuring of the unit?the in-circuit sweeps of completed units we've seen haven't shown any ringing, so i wouldn't worry too much.
Volker, are the steps in the Excel sheet calculated for 1db attenuation per step? If not, can you tell me about?[silent:arts] said:the rotary switches
you would better want it exponential (or log in potentiometer language).
it took some time to figure this out, but with some help I was able to do an Excell sheet to calculate the resistors for emulating a real log potentiometer.
fill in the desired steps you want: Log Pot to Switch Excell Sheet
you may want it in dB steps (like me). at the end it is a series attenuator.
my prototype has 18dB of gain, thus I will do one dB steps on an Elma, stopped to 23 steps, going from -4dB to +18dB.
Of course, round the numbers, I've been precise to let you choose the closer value... I will do the sameMoby said:;D Thanks... I was always poor in math so I will round the numbers
You don't really need shorting switches for the time constants IMO. The only thing that will occur will be weird attack/release during the switching operation... It will take a few microseconds to go from one step to another so...Mr. Snoid said:I scored some cheap retired grayhill 70BFD30s for Fabio's 1270 build a while ago and was wondering if I SHOULD use them as Time Constant switches.
The problem is they are non-shorting, but I could stop them to 6-8-or even 10 position and solder the resistors to the PC board connectors. Would save a few bucks...but is the non-shorting issue a big deal? Could it be compensated for easily with a cap perhaps?
Or should I just say "Fuck it" and buy some 2x6 Lorlins? It's only money, right????
Tod
If you've got time enough, it's certainly better to match them, but stuffing those switches is already a long work so... If you take 1% resistors, your switches will be matched certainly at less than 2% ( 2% is the worst possibility if you buy following resistors in the same bobin )... It's always better than any pot !!! ;DSaMpLeGoD said:Quick question, for threshold and gain ,I bought on ebay 4x 24 steps rotary switchhes with double deck for my PM670... just need to ask one thing: the values obtained in the Volker's datasheet need to be present in each deck... matched??
But the gain switches don't seem to work.
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