This is so incredible. I might try to make a line level compressor circuit using this as inspiration. It would definitely be a fun project if nothing else.
A disadvantage of this montage is when a song ends, there is a short spike in volume if the next song begins briefly 🎵. So I can't use it for music anymore. Always useful for regulating sounds in films and videos. Here, 2 x 10W power amplifier (internal power supply of 24 Volt minimum), Christmas garland bulbs 5V 100mA 🎄directly in series with 2 desktop speakers 🔊. Hello from Belgium 🙂🙋
Very interesting video. Congrats. I was searching for an effective way to tame high peaks in my tv audio system and this seems to be what I'm looking for. I know that the attack time is not that fast, but it seems to be very natural in your device. Although I'm worried about the difference in ground, since my amplifier is in a BTL configuration. May I use the same bulbs just connecting them in series with the + wires of the speakers for a btl class-d amplifier 16W@8Ohms (tpa3116d2) to avoid a short in ground?
Congratulations for the video. I would like to assemble, but I don't know anything about electronics. I could put the components in the description, and if possible a video assembling step by step. Thanks. You have already won another subscriber. Google translator
There are incandescent bulbs like 2.5V-3V 20mA for which use of relatively high THD of even the best of the best power amplifiers is not necessary. Its just a matter of searching for them as their production stopped long ago. Early compressors, especially for stage musical instrumens used opticly coupled incandescent bulb and LDR, but they are not suitable for demonstrated here application as LDRs introduce audible noise.
Hi, love the idea of one of these! I've tried building your simplest circuit, I'm passing line level out of my interface, through the bulb and then back again, I'm getting signal but the bulb isn't showing any signs of life. I'm using a 6v 150mA bulb like yourself. Could it be my line level just doesn't have enough oomph to drive the bulb? Would be really grateful for your help!
This is really cool, I made a simple compressor but unlike me you seem to actually know what you're doing xP Have you shared this on any DIY audio forums?
I'm not sure I'm understanding the benefit! everybody goes on about you don't want to have compression in your music you want "high dynamic range" why is this compressor breaking that norm? what is the benefit what does it give you sonically? thanks!
Okay. So, I can't say for certain where you are hearing this information, and in what context, so this is some amount of guesswork on my part... Modern music is highly compressed. When you squash the dynamic range through compression and limiting, you are able to control peak levels to meet the standards of streaming platforms, while still having the quieter parts of your song at a level that is still very much in the listener's ear, in such a way that it commands their attention. Even beyond streaming platforms, the 90s was notorious for having a "loudness war", where nearly all major releases were mixed and mastered to be highly compressed. They sound somewhat terrible, but it's a very "in your face" style of mixing that lends itself to songs competing for attention, at the expense of what a listener will hear when they are listening attentively. In such cases, the loss in terms of dynamic range can actually make mixes sound simultaneously abrasive and boring (a contradiction that heavy compression somehow manages to pull off). The purpose for something like this is that it is a smoother form of compression, and it can be applied to music that was recorded under different circumstances. Live performances, or recordings that were recorded when tape or vinyl were the only recording medium, or early stages of digital, before folks really got the hang of it are music that would probably do well with this sort of compression, because the constraints of the recording process tends to gravitate toward trying to slam the recorder with a hot signal to create a high dynamic range against a relatively high noise floor, resulting in clipping. While most of this will be fixed in mastering, anything that hasn't been remastered (say, an original pressing of a live album, or an experimental concept album from the 70s, or a home-produced tape of a friend playing guitar, or some obscure release from a now defunct record label where remastering just isn't going to happen), or anything that was mastered in an abrasive way can be fixed on the listener's end. And the truth is, even when compression is present, the idea is that this form of compression works exceptionally well because the curve of the compression is applied in a way that is proportional to the voltage (volume) being produced, rather than the compression "kicking in" at a certain volume, and so it inherently preserves most of the dynamic range, but just kind of rounds of as you approach peak levels. There is a minimum to activate the compressor, but the compression is happening as a result of physics creating resistance as voltages increase the temperature in the bulb, rather than a circuit designed to kick in and choke off the signal at a certain threshold.
Classic Audio, what circuit schematic would you use for a PASSIVE guitar compressor? the guitar pickups that connect to a passive guitar compressor would be what circuit schematic?
Hi Wayne, I would put it after the first power amplifier rated for 10W or more and then connect the output to another power amplifier. The same rules should apply as here!
@@Psychotenuseyou could probably also put a signal boost in front of it like a full range booster. Then you could drive the compressor with quieter signals like a guitar. Might be nice as part of a microphone preamp with a single 12ax7 wired in parallel driving the compression circuit. Maybe another post compressor as a makeup stage.
If you’re feeding it a line level signal from a mic pre yes you can. If your feeding it a mic level signal... load... then likely not. You could add a switch to select the input load by installing a transformer that can have an input load of 600-1000 ohms (line) or 10k-50k ohms(mic). Secondary would be 600-1000 ohm. 1:1 (line)or a 10:1(mic) ratio. Someone please correct this if I’m wrong about the mic loads.
It needs to be driven from the output of a single ended (not bridge-tied-load) power amplifier. Connect your microphone to a suitable microphone pre-amplifier and power amplifier and feed the output of the compressor into a line input. After you've done that you can put any audio signal you want through it.
@@jacksonreazin6042 Both more voltage and more current are needed, so much more power overall. The best line outputs such as the ones that use NE5532 op-amps on split 17V rails (the minority unfortunately) will only be able to give you about 20mA at 10V RMS on a good day, and that depends on whether you have enough gain and correct gain architecture in the system to get the level up to 10 times the normal operating level. This unit wanted a good 200mA peak and about 12V RMS to work correctly. A power amplifier will be able to do this easily whereas any line output will go into overload long before reaching this level. Being a passive circuit, it can only attenuate, so to get it up to the right operating level, something a lot more beefy than a line output is needed. Hope that helps!
where would be the best place to get 6v bulbs? like what are they typically used for? closest ive found so far is speedometer bulbs but they are 3w. any response would be greatly appreciated thanks :)
Better put the light bulbs direct on the midrange loudspeaker and/or tweeter. Why? because you dont want to take away the bass from the bass loudspeaker.
Great project with a fantastic presentation! I'm curious to know if it would be possible to make a passive Limiter circuit. Perhaps Zener Diodes would suffice for such an idea. I've recently seen the creator of Air Windows present his ideas on a passive circuit design to achieve desirable characteristics in audio recording/mixing/mastering inspired by the Gyraf Gyratec XXI. It would be fantastic to marry your Passive Thermal Compressor with his passive analog Saturator design. Considering the simplicity of each respective circuit, I feel it's possible!
I impulsively ordered a pack of incandescent 6v bulbs not too long ago.
Looks like I know what they'll be getting used for now.
Thanks & One Love !
A+ great topic, project and explanation! Hope you produce more videos like this in the future. Btw loved the "snake oil alert".
Glad you enjoyed the snake oil reference! Hopefully it'll feature a little bit more on this channel now I have the time to work on it!
This is so incredible. I might try to make a line level compressor circuit using this as inspiration. It would definitely be a fun project if nothing else.
Really interesting! 👍 Great work.
I would love to have this compressor built into a solid state micro guitar amp. Could make a great clean sound
Excellent and very clever. Thanks.
Glad you enjoyed it!
A disadvantage of this montage is when a song ends, there is a short spike in volume if the next song begins briefly 🎵. So I can't use it for music anymore. Always useful for regulating sounds in films and videos. Here, 2 x 10W power amplifier (internal power supply of 24 Volt minimum), Christmas garland bulbs 5V 100mA 🎄directly in series with 2 desktop speakers 🔊. Hello from Belgium 🙂🙋
Good video !
Very interesting video. Congrats. I was searching for an effective way to tame high peaks in my tv audio system and this seems to be what I'm looking for. I know that the attack time is not that fast, but it seems to be very natural in your device. Although I'm worried about the difference in ground, since my amplifier is in a BTL configuration. May I use the same bulbs just connecting them in series with the + wires of the speakers for a btl class-d amplifier 16W@8Ohms (tpa3116d2) to avoid a short in ground?
Congratulations for the video. I would like to assemble, but I don't know anything about electronics. I could put the components in the description, and if possible a video assembling step by step. Thanks. You have already won another subscriber. Google translator
Hmm... I'm probably not the best person to teach assembly, should be lots of videos out there on how to solder etc. a lot better than I could make!
Only problem is that the schematic is almost unreadable in the video. Can you insert it in the bottom notes?
Nice..but can we somehow mod it to be able to use it with just a preamplifier, in order to use it on a live show lines...?
There are incandescent bulbs like 2.5V-3V 20mA for which use of relatively high THD of even the best of the best power amplifiers is not necessary. Its just a matter of searching for them as their production stopped long ago. Early compressors, especially for stage musical instrumens used opticly coupled incandescent bulb and LDR, but they are not suitable for demonstrated here application as LDRs introduce audible noise.
LDRs are very quiet if we use them at low impedance, say 6dB of attenuation at 10k, it's easy to get the noise below 10uV.
@@michaelfidler8218 Small size modern fast ones - yes. 50 years ago they were quite innert and noisy.
do have a link to this type of bulb? i love that this doesn't need a LDR and you can directly see the compression
Hi, love the idea of one of these! I've tried building your simplest circuit, I'm passing line level out of my interface, through the bulb and then back again, I'm getting signal but the bulb isn't showing any signs of life. I'm using a 6v 150mA bulb like yourself. Could it be my line level just doesn't have enough oomph to drive the bulb? Would be really grateful for your help!
Hi Ed - you need a power amp to drive the compressor. A line output won't come close!
This is really cool, I made a simple compressor but unlike me you seem to actually know what you're doing xP
Have you shared this on any DIY audio forums?
Not really, it was a bit of a video editing exercise in a spare week I had during lockdown.
I'm not sure I'm understanding the benefit! everybody goes on about you don't want to have compression in your music you want "high dynamic range" why is this compressor breaking that norm? what is the benefit what does it give you sonically? thanks!
That's my question!
Okay.
So, I can't say for certain where you are hearing this information, and in what context, so this is some amount of guesswork on my part...
Modern music is highly compressed. When you squash the dynamic range through compression and limiting, you are able to control peak levels to meet the standards of streaming platforms, while still having the quieter parts of your song at a level that is still very much in the listener's ear, in such a way that it commands their attention. Even beyond streaming platforms, the 90s was notorious for having a "loudness war", where nearly all major releases were mixed and mastered to be highly compressed.
They sound somewhat terrible, but it's a very "in your face" style of mixing that lends itself to songs competing for attention, at the expense of what a listener will hear when they are listening attentively. In such cases, the loss in terms of dynamic range can actually make mixes sound simultaneously abrasive and boring (a contradiction that heavy compression somehow manages to pull off).
The purpose for something like this is that it is a smoother form of compression, and it can be applied to music that was recorded under different circumstances.
Live performances, or recordings that were recorded when tape or vinyl were the only recording medium, or early stages of digital, before folks really got the hang of it are music that would probably do well with this sort of compression, because the constraints of the recording process tends to gravitate toward trying to slam the recorder with a hot signal to create a high dynamic range against a relatively high noise floor, resulting in clipping. While most of this will be fixed in mastering, anything that hasn't been remastered (say, an original pressing of a live album, or an experimental concept album from the 70s, or a home-produced tape of a friend playing guitar, or some obscure release from a now defunct record label where remastering just isn't going to happen), or anything that was mastered in an abrasive way can be fixed on the listener's end.
And the truth is, even when compression is present, the idea is that this form of compression works exceptionally well because the curve of the compression is applied in a way that is proportional to the voltage (volume) being produced, rather than the compression "kicking in" at a certain volume, and so it inherently preserves most of the dynamic range, but just kind of rounds of as you approach peak levels. There is a minimum to activate the compressor, but the compression is happening as a result of physics creating resistance as voltages increase the temperature in the bulb, rather than a circuit designed to kick in and choke off the signal at a certain threshold.
Can you build a small amplification circuit that could be used as the drive the circut. Thanks and great video!
I should think so! Maybe one of those eBay TDA2020 type chip-amp boards would work well.
Classic Audio, what circuit schematic would you use for a PASSIVE guitar compressor? the guitar pickups that connect to a passive guitar compressor would be what circuit schematic?
I imagine you could use this for guitar by putting it between your amp and a powered cab.
Hi Wayne, I would put it after the first power amplifier rated for 10W or more and then connect the output to another power amplifier. The same rules should apply as here!
@@Psychotenuseyou could probably also put a signal boost in front of it like a full range booster. Then you could drive the compressor with quieter signals like a guitar. Might be nice as part of a microphone preamp with a single 12ax7 wired in parallel driving the compression circuit. Maybe another post compressor as a makeup stage.
Can I used this for vocals
If you’re feeding it a line level signal from a mic pre yes you can. If your feeding it a mic level signal... load... then likely not. You could add a switch to select the input load by installing a transformer that can have an input load of 600-1000 ohms (line) or 10k-50k ohms(mic). Secondary would be 600-1000 ohm. 1:1 (line)or a 10:1(mic) ratio. Someone please correct this if I’m wrong about the mic loads.
It needs to be driven from the output of a single ended (not bridge-tied-load) power amplifier. Connect your microphone to a suitable microphone pre-amplifier and power amplifier and feed the output of the compressor into a line input. After you've done that you can put any audio signal you want through it.
@@michaelfidler8218 ok, so, because of the light bulb more wattage is needed than a line output?
@@jacksonreazin6042 Both more voltage and more current are needed, so much more power overall. The best line outputs such as the ones that use NE5532 op-amps on split 17V rails (the minority unfortunately) will only be able to give you about 20mA at 10V RMS on a good day, and that depends on whether you have enough gain and correct gain architecture in the system to get the level up to 10 times the normal operating level. This unit wanted a good 200mA peak and about 12V RMS to work correctly. A power amplifier will be able to do this easily whereas any line output will go into overload long before reaching this level. Being a passive circuit, it can only attenuate, so to get it up to the right operating level, something a lot more beefy than a line output is needed.
Hope that helps!
@@michaelfidler8218 absolutely!
How would I adapt this to be used as a guitar pedal? Would I just boost the signal into it? Or use a lower powered bulb?
Boost, gain or overdrive it. Either way it wants more power.
where would be the best place to get 6v bulbs? like what are they typically used for? closest ive found so far is speedometer bulbs but they are 3w. any response would be greatly appreciated thanks :)
eBay perhaps would do for a small quantity?
bulb from old Christmas wreath 🎄👍🙂
Better put the light bulbs direct on the midrange loudspeaker and/or tweeter. Why? because you dont want to take away the bass from the bass loudspeaker.
for example 12V 10W works well to protect tweeters 👍🙂
Great project with a fantastic presentation!
I'm curious to know if it would be possible to make a passive Limiter circuit. Perhaps Zener Diodes would suffice for such an idea.
I've recently seen the creator of Air Windows present his ideas on a passive circuit design to achieve desirable characteristics in audio recording/mixing/mastering inspired by the Gyraf Gyratec XXI.
It would be fantastic to marry your Passive Thermal Compressor with his passive analog Saturator design. Considering the simplicity of each respective circuit, I feel it's possible!
Interesting!
Thanks!
Hiiiiiiiii