Gain of audio amplifier?

Thread Starter

Arjune

Joined Jan 6, 2018
354
A good education gets you a well paid job.
My government brings poor refugees to my country, gives them a hotel, food and a job.
I am old (78) and retired so I do not have a job anymore. My government pays me to do anything I want to do because for many years I paid them taxes.
All my medical bills and medications are paid by my government.
The value of my home, investments and bank accounts keep growing.
I am happy for you audio guru. What country would that be by the way? Oh I see it's Canada and I always thought they were kind people there. Can you buy one of my books on my website?
 

Thread Starter

Arjune

Joined Jan 6, 2018
354
C20 and C21 were removed and R12 and R13 were changed to 1meg for a gain of 100. I would send this to a line amplifier with a gain of three for each microphone. Does anyone see a problem with the one Meg resistors? M-diy-5532-v2 board3f525c6c8d684ba6a7f3cfa2a0569448.png3f525c6c8d684ba6a7f3cfa2a0569448.png
 

Thread Starter

Arjune

Joined Jan 6, 2018
354
C20 and C21 were removed and R12 and R13 were changed to 1meg for a gain of 100. I would send this to a line amplifier with a gain of three for each microphone. Does anyone see a problem with the one Meg resistors? M-diy-5532-v2 boardView attachment 302388View attachment 302388
Can I change R11 and R16 to 1
C20 and C21 were removed and R12 and R13 were changed to 1meg for a gain of 100. I would send this to a line amplifier with a gain of three for each microphone. Does anyone see a problem with the one Meg resistors? M-diy-5532-v2 boardView attachment 302388View attachment 302388
Can I change R11&R16 to 1meg and remove C11&C14 and use the LF353 for the guitars?
 

Audioguru again

Joined Oct 21, 2019
6,826
Your preamp has no power supply voltage!
C18 and C19 are too small (inly 4.7nF) to pass medium and low audio frequencies. Use 470nF.
The preamp will produce hum and crosstalk unless a 4.7uF capacitor is parallel to R7.
 

Thread Starter

Arjune

Joined Jan 6, 2018
354
Your preamp has no power supply voltage!
C18 and C19 are too small (inly 4.7nF) to pass medium and low audio frequencies. Use 470nF.
The preamp will produce hum and crosstalk unless a 4.7uF capacitor is parallel to R7.
C18 & C19 are electrolytic capacitors which seems to be around 10 microfarads. You mean R 17 should have a 4.7 microfarad capacitor to ground-there is no R7? The IC part number has not been sanded off. What do you mean no power supply voltage. It is using about 3 milliamps at 10 volts. Have you been observing me where you are because you only see 3 milliamps according to my test with the multimeter and you're baffled?
 

Audioguru again

Joined Oct 21, 2019
6,826
Yes, the added capacitor should be parallel with R17.
Your schematic shows no very important supply voltage. Maybe you said the voltage 27 posts ago.
Why did your schematic wrongly show 4.7nF for C18 and C19 that cut medium and low audio frequencies?
 

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