Any coupling from input to output ... um ... couples unwanted noise on the input, over to the output. In this case the coupling mechanism is a Y capacitor.
Remember that the ~400pF in-to-out capacitor forms a capacitive voltage divider with the out-to-ground capacitor inside the SMPS. Vout = Vin * (Csmall / (Csmall + Cbig)). If Csmall = 400pF and Cbig = 33uF then Vout = Vin * 1.2E-5 . Assuming that the 33uF capacitor continues to behave as a capacitor at 100 kHz, of course. Its impedance needs to be 48 milliohms or less, at 100 kHz. Which is quite achievable.
Remember that the ~400pF in-to-out capacitor forms a capacitive voltage divider with the out-to-ground capacitor inside the SMPS. Vout = Vin * (Csmall / (Csmall + Cbig)). If Csmall = 400pF and Cbig = 33uF then Vout = Vin * 1.2E-5 . Assuming that the 33uF capacitor continues to behave as a capacitor at 100 kHz, of course. Its impedance needs to be 48 milliohms or less, at 100 kHz. Which is quite achievable.
I have a huge stock of these, and use them for these connections:
120x Male To Female Dupont Wire Jumper Cable Connectors For Arduino Breadboards | eBay
Jan
120x Male To Female Dupont Wire Jumper Cable Connectors For Arduino Breadboards | eBay
Jan
Hi Jan,
I was directed here from diyaudiostore. I would like to use your SilentSwitcher as a microphone preamplifier but I'm not sure how to wire everything together. Can you help me please?
I understand the input and output of the SilentSwitcher but I'm confused about how to then connect the microphone to my recorder. Please see this crude diagram of what I'm talking about: Imgur: The magic of the Internet
Do I just splice the output of the SilentSwitcher into a normal 3.5mm audio cable?
Thanks for your help and sorry about my lack of knowledge.
https://imgur.com/nuROAjahttps://imgur.com/nuROAja
I was directed here from diyaudiostore. I would like to use your SilentSwitcher as a microphone preamplifier but I'm not sure how to wire everything together. Can you help me please?
I understand the input and output of the SilentSwitcher but I'm confused about how to then connect the microphone to my recorder. Please see this crude diagram of what I'm talking about: Imgur: The magic of the Internet
Do I just splice the output of the SilentSwitcher into a normal 3.5mm audio cable?
Thanks for your help and sorry about my lack of knowledge.
https://imgur.com/nuROAjahttps://imgur.com/nuROAja
I think there may be a confusion here. The SilentSwitcher is a very low noise power supply, and it can surely feed a microphone amplifier if the voltage requirements match, but it is not an amplifier in itself.
The picture you show appears to be of a digital recorder with build-in microphones, so I don't know exactly what you need.
Are you suggesting to power the digital recorder with the silentswitcher?
Jan
The picture you show appears to be of a digital recorder with build-in microphones, so I don't know exactly what you need.
Are you suggesting to power the digital recorder with the silentswitcher?
Jan
Hi Jan, thanks for your quick response.
Sorry about the confusion. I am trying to power an external microphone that can accept up to 10v with the SilentSwitcher. I want to use the SilentSwitcher to power the microphones because the internal preamp of the recorder is rather noisy and I want to lower the noise floor.
I still need the recorder to actually record the audio to an SD card so I need to get the audio from the microphone into the device. The device has a 3.5mm mic input.
Does this make sense and is it possible?
Sorry about the confusion. I am trying to power an external microphone that can accept up to 10v with the SilentSwitcher. I want to use the SilentSwitcher to power the microphones because the internal preamp of the recorder is rather noisy and I want to lower the noise floor.
I still need the recorder to actually record the audio to an SD card so I need to get the audio from the microphone into the device. The device has a 3.5mm mic input.
Does this make sense and is it possible?
OK I see what you mean. But question then is: do you have an external mike that has it's own amplifier? I assume that the external mike input of the recorder accepts some kind of signal from an amplified mike, or can it accept 'just' the mike, and then use its internal amplifier?
This is important to know. What is the type/brand of the recorder, I can look it up for you.
Jan
jfet phono preamp powered with your SS
I need to get 24v so i would like to know which
I built am audio's Dual mono RIAA JFET phono preamp. It's in it's enclosure only awaiting your power supply board!
It needs 24v from what i have been reading. I am not an extremely experienced person in the electronics field, but i have been tinkering and building a bunch of stuff, I am having fun, a lot of it!
so back to my question what are the exact resistors i need to buy to be able to achieve 24v with your power supply board? And the procedure to do it!?
I will be powering this with a power bank made out of 18650 Batteries in a Holder Case...
If you have a more detailed document i would greatly appreciate the documentation and guidance.
thank you for this, I am impatiently waiting for this oin the mail... next week!!!
I need to get 24v so i would like to know which
I built am audio's Dual mono RIAA JFET phono preamp. It's in it's enclosure only awaiting your power supply board!
It needs 24v from what i have been reading. I am not an extremely experienced person in the electronics field, but i have been tinkering and building a bunch of stuff, I am having fun, a lot of it!
so back to my question what are the exact resistors i need to buy to be able to achieve 24v with your power supply board? And the procedure to do it!?
I will be powering this with a power bank made out of 18650 Batteries in a Holder Case...
If you have a more detailed document i would greatly appreciate the documentation and guidance.
thank you for this, I am impatiently waiting for this oin the mail... next week!!!
I wish I knew more about it, like i said in the email, this came with not much information at all.
that is all there is on am audio's website:
"Mini-Max two gain stage design, minimum parts for the maximum sound quality
Based on well-known Le Pacific passive RIAA equalization topology
Dual mono layout to minimize Stereo Crosstalk
Famous TOSHIBA 2SK170 JFET in amplifier stages
Russian Paper-In-Oil capacitors in signal path
PCB carefully design for the best audio performance
Active power filter using capacitance multiplier
Low noise 1% resistors
Low ESR ELNA power filter’s capacitors
Gain ~ 100V/V (~40dB)
One channel shown"
nothing more on his ebay page or in the documentation sent with the kit...
so i dont know for sure, I was expecting something in the package or on the web but... no more info from the seller.
I found the 24v info here on this website actually.
that is all there is on am audio's website:
"Mini-Max two gain stage design, minimum parts for the maximum sound quality
Based on well-known Le Pacific passive RIAA equalization topology
Dual mono layout to minimize Stereo Crosstalk
Famous TOSHIBA 2SK170 JFET in amplifier stages
Russian Paper-In-Oil capacitors in signal path
PCB carefully design for the best audio performance
Active power filter using capacitance multiplier
Low noise 1% resistors
Low ESR ELNA power filter’s capacitors
Gain ~ 100V/V (~40dB)
One channel shown"
nothing more on his ebay page or in the documentation sent with the kit...
so i dont know for sure, I was expecting something in the package or on the web but... no more info from the seller.
I found the 24v info here on this website actually.
here is the only thread i've found some information
AM Audio’s RIAA JFET Phono Preamplifier Kit | Audiokarma Home Audio Stereo Discussion Forums
"Stud is my ground, copper alligator clips go to my 2 12v SLA batteries, wired in series for 24v."
that is where I got the 24v bit...
AM Audio’s RIAA JFET Phono Preamplifier Kit | Audiokarma Home Audio Stereo Discussion Forums
"Stud is my ground, copper alligator clips go to my 2 12v SLA batteries, wired in series for 24v."
that is where I got the 24v bit...
On the silentswitcher board, there are four open resistor positions, marked RX1 to RX4. To set the output to +/-24V, populate these positions as follows:
RX1: 80.6k
RX2: 96.5k
RX3: 121k
RX4: 127k
These resistors should be size 1206 SMD, either thick-film or thin-film. They should be available from the usual suspects like Mouser or Digikey.
Be aware that the 24V version can only provide 50 - 60 mA output current per polarity, as the inductors have been optimized for 12 to 15V. But within those constraints, the performance will be identical to the main version.
Jan
RX1: 80.6k
RX2: 96.5k
RX3: 121k
RX4: 127k
These resistors should be size 1206 SMD, either thick-film or thin-film. They should be available from the usual suspects like Mouser or Digikey.
Be aware that the 24V version can only provide 50 - 60 mA output current per polarity, as the inductors have been optimized for 12 to 15V. But within those constraints, the performance will be identical to the main version.
Jan
this isn't me it's a quote i took from a post on the website where i got most my information about this pre-amp.
this person did use 2 sla batteries because it's pure DC. He also used an external step up transformer for his MC cartrige phono player.
thank you for the information, I wont cancel my order and do this myself. I am excited.
If you think i should know anything else or anything i should be carefull of let me know!
thanks again!
this person did use 2 sla batteries because it's pure DC. He also used an external step up transformer for his MC cartrige phono player.
thank you for the information, I wont cancel my order and do this myself. I am excited.
If you think i should know anything else or anything i should be carefull of let me know!
thanks again!