Hi Don,
Gerber files sent.
The DIY FE 2022 draws very little current, just a bit over 10mA per channel. If I was using it as a front end built into an amplifier i would have powered it with the amplifier's power supply, with a local RC filter for additional power supply filtration. However I built it as a stand alone preamp. Since the DIY FE 2022 draws such little current it would not have made sense to power it with an amplifier power supply that is capable of providing many Amperes of current.
It was also an excuse to play with KiCad. 🤓
Also note that for the 62VDC output of my power supply build, the power transformer secondary of the transformer that I used, the Triad VPT 48-520 secondary measured 57VAC under load, and the unregulated rectified voltage was 75VDC. So it is misleading that 48VAC transformer secondary is enough for a final regulated 62VDC.
Gerber files sent.
The DIY FE 2022 draws very little current, just a bit over 10mA per channel. If I was using it as a front end built into an amplifier i would have powered it with the amplifier's power supply, with a local RC filter for additional power supply filtration. However I built it as a stand alone preamp. Since the DIY FE 2022 draws such little current it would not have made sense to power it with an amplifier power supply that is capable of providing many Amperes of current.
It was also an excuse to play with KiCad. 🤓
Also note that for the 62VDC output of my power supply build, the power transformer secondary of the transformer that I used, the Triad VPT 48-520 secondary measured 57VAC under load, and the unregulated rectified voltage was 75VDC. So it is misleading that 48VAC transformer secondary is enough for a final regulated 62VDC.
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Thanks Dirk…no doubt…I had the stock left over from a MoFo build & wanted to get the pre small. Now to fab Al sides!!
The nice thing is - you can screw any kind of materials on it. I also use aluminum for shielding. But I also used double layer covers
made of a inner layer of ALU and a outer layer of black plexiglass (acrylglass). Many options...
Greets
Dirk
made of a inner layer of ALU and a outer layer of black plexiglass (acrylglass). Many options...
Greets
Dirk
A dumb question to ask if I may. Can it be powered with a simple 24v DC PSU? Try to avoid toroidal transformer and power supply board but powered directly from 24v DC power supply brick laying around.
It can be.
However the distortion will be higher.
The maximum output voltage will be about 8Vrms. If you are using it with a follower amplifier, the maximum power output would be less than 8W into 8 Ohm.
So it depends on what you want and what you can live with.
However the distortion will be higher.
The maximum output voltage will be about 8Vrms. If you are using it with a follower amplifier, the maximum power output would be less than 8W into 8 Ohm.
So it depends on what you want and what you can live with.
By the way, 48V wall plug-in smps power supplies are available:
https://www.digikey.ca/en/products/detail/cui-inc/SDI36-48-U-P5/9817247?gclsrc=aw.ds&&utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Zombie SKUs&utm_term=&productid=9817247&utm_content=General&utm_id=go_cmp-17855401585_adg-_ad-__dev-c_ext-_prd-9817247_sig-EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYBCABEgIXEPD_BwE&gad_source=1&gad_campaignid=17336435733&gbraid=0AAAAADrbLliHDbbYYU7Zi4QftBX9zvPTq&gclid=EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYBCABEgIXEPD_BwE&gclsrc=aw.ds
https://www.digikey.ca/en/products/detail/mean-well-usa-inc/GST36B48-P1J/7703690?gclsrc=aw.ds&&utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Zombie SKUs&utm_term=&productid=7703690&utm_content=General&utm_id=go_cmp-17855401585_adg-_ad-__dev-c_ext-_prd-7703690_sig-EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYAiABEgJPf_D_BwE&gad_source=1&gad_campaignid=17336435733&gbraid=0AAAAADrbLliHDbbYYU7Zi4QftBX9zvPTq&gclid=EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYAiABEgJPf_D_BwE&gclsrc=aw.ds
Looking at the specs, the Mean Well has lower ripple at 200mVp-p whereas the CUI has 480mVp-p.
By the way they were from the Digikey Canadian website but I had set the prices at USD.
https://www.digikey.ca/en/products/detail/cui-inc/SDI36-48-U-P5/9817247?gclsrc=aw.ds&&utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Zombie SKUs&utm_term=&productid=9817247&utm_content=General&utm_id=go_cmp-17855401585_adg-_ad-__dev-c_ext-_prd-9817247_sig-EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYBCABEgIXEPD_BwE&gad_source=1&gad_campaignid=17336435733&gbraid=0AAAAADrbLliHDbbYYU7Zi4QftBX9zvPTq&gclid=EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYBCABEgIXEPD_BwE&gclsrc=aw.ds
https://www.digikey.ca/en/products/detail/mean-well-usa-inc/GST36B48-P1J/7703690?gclsrc=aw.ds&&utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Zombie SKUs&utm_term=&productid=7703690&utm_content=General&utm_id=go_cmp-17855401585_adg-_ad-__dev-c_ext-_prd-7703690_sig-EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYAiABEgJPf_D_BwE&gad_source=1&gad_campaignid=17336435733&gbraid=0AAAAADrbLliHDbbYYU7Zi4QftBX9zvPTq&gclid=EAIaIQobChMI7ILMjKjfjAMVHgitBh0GeBNBEAQYAiABEgJPf_D_BwE&gclsrc=aw.ds
Looking at the specs, the Mean Well has lower ripple at 200mVp-p whereas the CUI has 480mVp-p.
By the way they were from the Digikey Canadian website but I had set the prices at USD.
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If I were to build this preamp again, this is the power supply I would use. The SMPS I used caused a high pitch squeal (it made hum sound good), which Nelson diagnosed correctly as a ground loop. I had to isolate the case of the SMPS and disconnect the ground from the IEC to the SMPS. I ended up with the SMPS case isolated using vinyl standoffs and then coating the metal enclosure under the SMPS for safety.
A wall wort or brick would have been so easy.....
Sounds like torture. I will stick to the inefficient linear/regulated supply.
Still, your build is very nice. 😎
Nor would I. Not for me. To each is own. That is the beauty of DIY.
I trust Chinese SMPS like I trust Chinese LED light technology.
Those things are torture devices for me at work.
I have to write waivers/disclaimers when I incorporate them into my work to protect my bottom.
I lost my notes(I threw them in the trash by mistake). The tone circuit adds like 0.01 distortion-ish. I thought it would be worse-ish. I have better OpAmps too-ish.
Most likely blasphemy to many but I think this is how my FE boards are going down.
With a relay selector and a million dollar volume pot I bought from Poland and some boring linear power supplies from yesteryear.
Most likely blasphemy to many but I think this is how my FE boards are going down.
With a relay selector and a million dollar volume pot I bought from Poland and some boring linear power supplies from yesteryear.
I run my FE and my ACA both off of a single Meanwell LRS-150-24 SMPS and they are totally quiet. The FE does have an SMPS filter on it but the ACA does not. The power supply is not mounted inside either chassis it just sits on the shelf behind everything and it never gets hot at all. It's a great little supply and they are only 16.99 on Amazon.
I need more than 20 dB gain for stage asked to amplify 50 to 500 Hz.
Any idea of how much one could get away with using FE2022? An extra 6 dB would be what I would like to use.
Not driving an output stage but Rahul's SCG.
Any advice, please.
Any idea of how much one could get away with using FE2022? An extra 6 dB would be what I would like to use.
Not driving an output stage but Rahul's SCG.
Any advice, please.
The standard values give 10x gain or 20dB. Additional 6dB would be 26db or 20x.
I do not know how the circuit would behave at 20x. Since this is DIY, you could change R3 and R4 and measure the performance. Or simulate it in LTSpice, although successful simulation does not guarantee success in real life. 🤓
Another factor is output voltage. The maximum output voltage is limited by power supply voltage and maximum power dissipation of the transistors.
I do not know how the circuit would behave at 20x. Since this is DIY, you could change R3 and R4 and measure the performance. Or simulate it in LTSpice, although successful simulation does not guarantee success in real life. 🤓
Another factor is output voltage. The maximum output voltage is limited by power supply voltage and maximum power dissipation of the transistors.
It will use a 55 volts power supply.
I am losing lots of gain using FIR filters (Acourate) so it is not as if it would be having to output more than it was.
I wish I was as good with LTSpice as you are, Mr. Mah! Add to that your measuring ability. Your circuit explorations ... You are a reference.
I am using a 20X version now.
I am losing lots of gain using FIR filters (Acourate) so it is not as if it would be having to output more than it was.
I wish I was as good with LTSpice as you are, Mr. Mah! Add to that your measuring ability. Your circuit explorations ... You are a reference.
I am using a 20X version now.