Toggle sidebar Toggle sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Compressor

brandon7861

brandon7861

Loose Wire
I Support WorldwideDX.com!
Nov 28, 2018
2,379
2,626
293
I never studied compressors, but I saw this video and thought it would be fun to try. I only had single op-amps but the plans call for two duals and a quad. Slapped some uv mask on the traces, still don't know why i do that, just makes it a mess. I still need to get the pots and a metal enclosure.

This is going to be one of the two boards for my home brew desk mic. I have no idea how well this will work for voice but I thought it would be worth a try.

20260427_113728.jpg

20260427_113742.jpg
 
  • Like
Reactions: MKwrench, Lawrence lin, Shadetree Mechanic and 3 others

I have built several different style compressor/processors, even sold some to locals that used quad op amps back when I was at school (long time back),
I have built them using discrete transistors & vogad IC's too,

Imho RF type clippers that operate on the principles seen on pa0fri.com out perform any audio based clipper/limiter type speech processor,

They can sound thin if the filter you use is narrow or you use a sharp crystal filter but they give your low power radio a BIG readability boost in a pileup.
 
  • Like
Reactions: brandon7861, AudioShockwav, sp5it and 1 other person
Thanks for all the input!!! I will definitely go with that approach.

This compressor will be repurposed for the TV. Tiffany likes to fall asleep to star trek and that orchestra volume at the beginning and end of every episode is brutal.

And that pa0fry circuit is nice, its all junk-box parts! I don't need to order anything to make that one.
 
Last edited:
  • Like
Reactions: Shadetree Mechanic and Cable Guy
I plan to use this on my uniden washington (initially) so I will have to power it externally. I need phantom power for the mic anyhow so it will already have external power in the desk mic base. I just need to make the wood base a little deeper to accommodate the boards. Thanks!
 
Or you could install our 4-pin mike socket adapter. Only uses pins 1,2 and 3. Pin 4 can be hacked as "phantom" power for a mike with active circuits.

Pricey, but it would make the desktop a bit neater.

https://www.ebay.com/itm/1167461842...pid=5336136228&customid=&toolid=10001&mkevt=1

I would put a 100 ohm or so resistor in line with the socket's pin 4 if you use it for mike power. That way if someone plugs a stock 4-pin Cobra mike into it, the mike's receive wire won't just short your mike power to ground.

73
 
nomadradio said:
This the basic design found in the Yaesu FT-101 radio before inflation made them leave it out from the "EE" models. Processing the RF signal is more effective than processing the audio.

73
Click to expand...
I have been saying that for years and years. When the new shack-in-a-box radios came out with audio processing everyone was WOW!!. The processor in my new at the time FT-857 could not hold a candle to the processor in my Kenwood TS-820S which uses RF processing. People would not believe me since a new fangled radio just HAD to be better than a 40+ year old radio with (GASP!!) tubes in the finals. Then I would switch between them and show them. Made a few enemies doing that. LOL
 
  • Like
Reactions: bob85 and Shadetree Mechanic
nomadradio said:
Or you could install our 4-pin mike socket adapter. Only uses pins 1,2 and 3. Pin 4 can be hacked as "phantom" power for a mike with active circuits.

Pricey, but it would make the desktop a bit neater.

https://www.ebay.com/itm/1167461842...pid=5336136228&customid=&toolid=10001&mkevt=1

I would put a 100 ohm or so resistor in line with the socket's pin 4 if you use it for mike power. That way if someone plugs a stock 4-pin Cobra mike into it, the mike's receive wire won't just short your mike power to ground.

73
Click to expand...
I have the uniden version with the 4 pin connector. I really want to use this on any radio though, so I would prefer not modding the washington in any way. Thanks!
 
brandon7861 said:
Thanks for all the input!!! I will definitely go with that approach.

This compressor will be repurposed for the TV. Tiffany likes to fall asleep to star trek and that orchestra volume at the beginning and end of every episode is brutal.

And that pa0fry circuit is nice, its all junk-box parts! I don't need to order anything to make that one.
Click to expand...
Making the volume of the commercials the same as the program would be nice. Do you plan to put this inside your TV?
 
Shadetree Mechanic said:
Making the volume of the commercials the same as the program would be nice. Do you plan to put this inside your TV?
Click to expand...
No. Our TV is getting up there in age. I should build it externally. I am surprised the TV has held on for this long. Besides, I don't want to redo this with SMD parts and thats probably the only way it would fit in anything modern.
 
  • Like
Reactions: Shadetree Mechanic
Brandon,

if you have a four pin washington, then it is the upd858 chassis, which already has a compressor type circuit built in.

I only mention this because you might want to bypass it when testing your external unit with this radio.

If i remember correctly the way this used to be done in the past was by lifting D20 and D21 and putting in a jumper to bypass them.
(its been a long time since i saw that mod so please don't quote me on that)

if you want to see what difference the built in compressor makes, just look at the difference in PEP output when using a 1k tone as opposed to saying "ahhh" into the mic.
LC
 
brandon7861 said:
I have the uniden version with the 4 pin connector. I really want to use this on any radio though, so I would prefer not modding the washington in any way. Thanks!
Click to expand...
I love this thread, I have gleaned so much. I have never thought about filtering mic audio on a rf level like that before it reaches the radio.

If your Washington has the 8719, it probably has a 5 pin like LC says. If it has a 4 pin, it may already have a solution similar to what Nomad offers. I have never seen a stock, 4 pin 8719 in the wild.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Spanish:
    Where do i upload schematics
  • @ BJ radionut:

    Items

    Amateur and CB Related Schematics and other Technical Resources
    www.worldwidedx.com www.worldwidedx.com
  • @ Catalyst 122:
    Who do I contact for a name change. I put in for it over a year ago and it says still under review.
  • @ BJ radionut:


      Top Bottom