Speaker Turn On Delay and DC Protector Board Set (V3)

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#221
Any decent resistor will do for the dc protect board. 1% if you have them is better, but 5 % will work too. The thermal drift of the resistor isn't going to matter unless the resistor is runnning close to it's power rating , then you want go to a higher wattage, not a higher tolerance or lower temp coefficient
 
#222
Thanks for answering AndrewT
I was looking for 33K 1/2W resistor at digikey for postition R2, R3, R4 on the DC protect board. But the 33k 1/2W resistor that come nearest to the specified is with 2% tol and temp coef +-200 PPM/C that digikey has on stock - would that be ok to use?

Best Regards
Rolle
 
#225
I just found a transformer (12,6Vac @ 2,5A) that I used for heater supply in a tube linestage some years ago. Would I be able to use this transformer to power the dc protect board with the 5v relays. I measured 13,1 Vac when connected to mains unloaded - is this to high for the 5v relays?
 
#227
Thanks AndrewT - The BOM specifies a 12Vac transformer when using the two 5V relays in series. I just wondered if I could put my 12,6Vac transformer to use again 🙂 But if it is too high, then I will not go down that road

Best Regards
Rolle
 
#231
zman01 said:
Sorry if this has been covered already - noticed that the Omron Electronics G5LA-14-CF-DC24 relay is obsolete and non-stocked at Mouser. Will the following work?

http://www.mouser.com/ProductDetail/TE-Connectivity/ORWH-SH-124D1F000

If anybody can chime in a suitable part number/model that can be swapped in, that would be great too.

Thanks in advance.
Click to expand...

The time i ordered the items I somewhere read that this one should fit

http://www.mouser.at/Search/Product...V-Fvirtualkey66710000virtualkey769-JS1F-12V-F

when you use the search function maybe you can find the original post. I haven't assembled my boards yet, so I can't give you any details if those one work. Furthermore they are 12V but I am sure they have similar ones for 24V!

all the best,
Phil
 
#232
zman01 said:
Sorry if this has been covered already - noticed that the Omron Electronics G5LA-14-CF-DC24 relay is obsolete and non-stocked at Mouser. Will the following work?

http://www.mouser.com/ProductDetail/TE-Connectivity/ORWH-SH-124D1F000

If anybody can chime in a suitable part number/model that can be swapped in, that would be great too.

Thanks in advance.
Click to expand...
i think the relay's are in series and hence you cant use 24 vdc relays, that would require 48 vdc supply or 35-40 vac to the pcb. whats your trafo voltage? choose relay coil voltage that approximately half your supply voltage, be it AC or DC. whoever told you to go for G5LA-14-CF-DC24?😕
 
#233
Thanks Phil and Prasi for your replies.

Prasi,

I found reference of the G5LA-14-CF-DC24 in the BOM.

I have a trafo with 2 x 12v aux voltage. I am guessing that I might have to use a small secondary transformer for projects that have main trafo w/o spare taps or aux voltage?
 
#234
zman01 said:
Thanks Phil and Prasi for your replies.

Prasi,

I found reference of the G5LA-14-CF-DC24 in the BOM.

I have a trafo with 2 x 12v aux voltage. I am guessing that I might have to use a small secondary transformer for projects that have main trafo w/o spare taps or aux voltage?
Click to expand...

WHich BOM are you referring to😕? the V3 BOM calls for
653-G5LA-14-CF-DC5 for 12 VACsupply
OR
653-G5LA-14-CF-DC12 for 24VAC supply
 
#238
#239
More noob questions 🙂

One of my projects is with a 25V transformer. Have not tested the transformer yet, but without load expecting 25-26.5 VAC output.

Would I be able to you the 24VAC version of the speaker protection board directly with this power transformer, or is the output voltage too high?
 
#240
use a 3pin regulator to get a usable DC voltage.

The DC from the 25Vac will be around 37Vdc. That is OK with an lm317
It is very near the maximum IN to OUT differential. but that only exists during startup. A Zener across IN to OUT protects the reg from overvoltage during start up, but you need a dropping resistor (current limiter) before the regulator to prevent the Zener from blowing up. This Zener also acts as the discharge protection for the regulator.
 
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