Help to understand schematics of Art ProMpa

Advertise with us
shop deals on amazon
Shop deals on ebay
GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
T

thegrupus

New member
Joined
Jun 26, 2015
Messages
4
Here the schematics attached,
On the power supply the C5,C6,C23 ,C16 (2200uF/16v ) are before the bridge diodes on the ac side this is normal?
And on the input mic what are de D16 D17 D19 D21 for ?

Thanks !
 

Attachments

  • 210_ProMPA_Schem.pdf
    159.3 KB · Views: 43
thegrupus said:
Here the schematics attached,
On the power supply the C5,C6,C23 ,C16 (2200uF/16v ) are before the bridge diodes on the ac side this is normal?
Click to expand...
Yes. they're part of a voltage doubler, that produces about 23V from a 12Vac transformer. The voltage-multiplier principle is also used to produce about 60V from the same 12Vac source. https://en.wikipedia.org/wiki/Voltage_multiplier


And on the input mic what are de D16 D17 D19 D21 for ?
Click to expand...
They are used for protection of the input stage against over voltages, particularly those that happen when the input is shorted to ground and capacitors C46/48 are charged at 48V.
 
nice trick the voltage doubler...

but why the protection diodes are connected to +/- 15v and not to ground?
 
thegrupus said:
nice trick the voltage doubler...

but why the protection diodes are connected to +/- 15v and not to ground?
Click to expand...

Any voltage over +15.7 (supply + led) will feed back to sup rail and not to next node, same for voltage below -15.7 to neg rail
If you clamp to ground, any voltage below -0.7 will not "pass" which is not what we want here,  symmetrical signal may have negative peak below -0.7V !

Best
Zam
 

Similar threads

J
Help understanding KM84 circuit (and other basic electronic principles…)
Replies
1
Views
593
rock soderstrom
rock soderstrom
T
DIY PSU for Altec 150A (M11) Coke Bottle.
2
Replies
38
Views
3K
thecr4ne
T
D
[BUILD] Quantum Audio QM8A-as-CAPI-312 Rebuild
Replies
5
Views
960
disjectia
D
Dr Tony Balls
Redd 47 Type Build Troubleshooting
Replies
5
Views
2K
rock soderstrom
rock soderstrom
T
Sennheiser MKH416T repair
2 3
Replies
55
Views
4K
Tubetec
T

Latest posts

Back
Top