[BUILD] fripholm's TG1 Zener Limiter boards - support thread
- Thread starter fripholm
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Help Support GroupDIY Audio Forum:
31cc7
Active member
Wow it looks great! I like the PSU shield as well. Congrats!
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dogma said:
As mentioned in the first post just drop me an email. There's also a link to the guide including BOM, optional front panel design etc. - see first post
And, as this question has come up frequently within the last weeks: The boards (limiter and PSU) are available!
echoplex said:andow do you mind posting some demos? preferably drums and 2bus
For the time being you could also check out the audio examples from this and this post.
fripholm said:
Thanks for the heads-up.. these two examples sound amazing!
I wonder if your PCB's is anywhere different than what Tat Prusha (DIY-Racked) offers.. he's also got a Zener Limiter in his portfolio.. I guess I better go with your PCBs tho
Since there were so many requests for audio demos I just ran some drums (from Addictive Drums) through my Zener Limiter.
https://www.dropbox.com/s/sjdzuigbb9bkfnv/drums_comp.wav?dl=0
https://www.dropbox.com/s/a8w6bnaf27ruu16/drums_lim.wav?dl=0
https://www.dropbox.com/s/v2vjxk7lycd1lpj/drums_thd.wav?dl=0
You can hear 4 bars through the limiter and then 4 bars the original signal. I just messed around till it sounded good, so I don't recall the settings. But these are rather extreme settings, so you can really hear it working....
https://www.dropbox.com/s/sjdzuigbb9bkfnv/drums_comp.wav?dl=0
https://www.dropbox.com/s/a8w6bnaf27ruu16/drums_lim.wav?dl=0
https://www.dropbox.com/s/v2vjxk7lycd1lpj/drums_thd.wav?dl=0
You can hear 4 bars through the limiter and then 4 bars the original signal. I just messed around till it sounded good, so I don't recall the settings. But these are rather extreme settings, so you can really hear it working....
shot
Well-known member
With too much time to spare (unfortunately!), I came back to finally tackle my TTx and find out what is wrong with my build!
I bought different zeners (1N5231) long time ago but had no time to swap them. Now I finally did that.
It solved all of my noises and nasty looking waveforms. Just like that. It's all good and I calibrated it without problem.
My final problem was that I did my own front panel that included both auto-release and hold controls. So I wrapped my head to try to find a solution how to make both possible. Even though Fripholm stated in his manual that it's not possible to have both, I managed to do so.
First I had to find how to wire it differently from the diagram that is in the build manual. That was rather easy. I didn't connect the wiper of the hold pot to the lower leg of R51, but instead I connected it to the pole of the A-R switch. The same pole that has to be disconnected from the ground. Wiper gets connected to that pole and it also has to be connected to the anode of the diode that is in parallel with the release pot and R51. This is basically the same as it's in build manual but it keeps the switch on the release pot active.
I had working Hold potentiometer but now it acted very weird. As soon as I moved from CCW position it would slam the GR meter all the way. I found out that it worked for few degrees of rotation but after that it was putting out simply too much voltage above the ground and that kicked massive amount of GR. Voltage from bottom leg of R58 was feeding CW with around 14Vdc if I remember correctly. And useful hold was up to 1.3Vdc coming out of the wiper. That was the voltage that maxed the gain reduction. So I tried to lower it down. I replaced R58 with 160K (!!) and left the lower leg of it in the air to be able to connect the CW directly to it. That worked! Now I had useful range of the Hold potentiometer. I kept the original 10K linear pot. I was curious if going from 6K2 to 160K changed the behavior of the compression so I took it off to compare. To my ears, compression was the same with Hold completely removed and R58 back to 6K2. So I decided to keep it with R58 at 160K and hold connected my way.
I have attached the schematic of how I connected it to this post. It's easier to draw it than to describe.
Now I'm a happy owner of another succesful build!
Btw, this compressor is amazing! Very different character from all the other compressors I've built so far (176, 160vu, 1176, LA4, Federal, Pico, GSSL...). I'll post some samples in few days.
Luka
I bought different zeners (1N5231) long time ago but had no time to swap them. Now I finally did that.
It solved all of my noises and nasty looking waveforms. Just like that. It's all good and I calibrated it without problem.
My final problem was that I did my own front panel that included both auto-release and hold controls. So I wrapped my head to try to find a solution how to make both possible. Even though Fripholm stated in his manual that it's not possible to have both, I managed to do so.
First I had to find how to wire it differently from the diagram that is in the build manual. That was rather easy. I didn't connect the wiper of the hold pot to the lower leg of R51, but instead I connected it to the pole of the A-R switch. The same pole that has to be disconnected from the ground. Wiper gets connected to that pole and it also has to be connected to the anode of the diode that is in parallel with the release pot and R51. This is basically the same as it's in build manual but it keeps the switch on the release pot active.
I had working Hold potentiometer but now it acted very weird. As soon as I moved from CCW position it would slam the GR meter all the way. I found out that it worked for few degrees of rotation but after that it was putting out simply too much voltage above the ground and that kicked massive amount of GR. Voltage from bottom leg of R58 was feeding CW with around 14Vdc if I remember correctly. And useful hold was up to 1.3Vdc coming out of the wiper. That was the voltage that maxed the gain reduction. So I tried to lower it down. I replaced R58 with 160K (!!) and left the lower leg of it in the air to be able to connect the CW directly to it. That worked! Now I had useful range of the Hold potentiometer. I kept the original 10K linear pot. I was curious if going from 6K2 to 160K changed the behavior of the compression so I took it off to compare. To my ears, compression was the same with Hold completely removed and R58 back to 6K2. So I decided to keep it with R58 at 160K and hold connected my way.
I have attached the schematic of how I connected it to this post. It's easier to draw it than to describe.
Now I'm a happy owner of another succesful build!
Btw, this compressor is amazing! Very different character from all the other compressors I've built so far (176, 160vu, 1176, LA4, Federal, Pico, GSSL...). I'll post some samples in few days.
Luka
Attachments
Hi everyone, I'm designing my own panel in FPE and get ready to put everything together, just a question is buzzing my head and I haven't find an answer in the whole thread.
What are the actual scales of input and output controls? I mean, the guide says 25db for the output and 36db for input, but how are distributed? (i.e. Input 0db to 36db? -36db to 0db? Something else? You get it ;D )
What are the actual scales of input and output controls? I mean, the guide says 25db for the output and 36db for input, but how are distributed? (i.e. Input 0db to 36db? -36db to 0db? Something else? You get it ;D )
These numbers are just a range as you can't predict the input level and even if you could, it's still a moving target because of all the calibrations that also affect the output.
However, none of the controls completely mute the signal. If you really want a scale with actual numbers, try from -18 to +18 for the input and +/- 13 at the input. Close enough if you're using 24-way rotary switches. It's a different story with pots... 8)
However, none of the controls completely mute the signal. If you really want a scale with actual numbers, try from -18 to +18 for the input and +/- 13 at the input. Close enough if you're using 24-way rotary switches. It's a different story with pots... 8)
thomb
Member
Hi guys,
i´m into the process of checking the wiring for this unit. I didn´t wire a lot of Transformer till now. So there are some questions. I use Haufe Input (RK381) and Output Transformer (RK494). In the picture you can see the Input Transformer. For 2:1 operation the secondary is wired in parallel.
1. Where to connect Pin 3/4 ?
2. Where to connect Pin 7 ?
3. Did someone successfully try to replace the 1N4153 / 1N483B with 1n4148 (Fripholm´s suggest 1N4148, but he did not try
them)?
The Forward current is different: 1n4153/1N483B (200mA, 1V)
1N4148 (300mA, 1V)
Thank´s a lot for the project and help.
Thomas
i´m into the process of checking the wiring for this unit. I didn´t wire a lot of Transformer till now. So there are some questions. I use Haufe Input (RK381) and Output Transformer (RK494). In the picture you can see the Input Transformer. For 2:1 operation the secondary is wired in parallel.
1. Where to connect Pin 3/4 ?
2. Where to connect Pin 7 ?
3. Did someone successfully try to replace the 1N4153 / 1N483B with 1n4148 (Fripholm´s suggest 1N4148, but he did not try
them)?
The Forward current is different: 1n4153/1N483B (200mA, 1V)
1N4148 (300mA, 1V)
Thank´s a lot for the project and help.
Thomas
Last edited:
Your diagram looks about right. Pin 7 (shield) usually connects to your chassis ground. Tie Pins 3/4 together at the transformer and then to GND somewhere on the board.
The forward current in the actual circuit is nowhere near the values from the datasheet so you should be fine with 1N4148 or similar diodes. The worst that could happen is that your threshold is a dB higher or lower compared to other diodes but that could also be true for different batches of the same type. Doesn't really matter...
The forward current in the actual circuit is nowhere near the values from the datasheet so you should be fine with 1N4148 or similar diodes. The worst that could happen is that your threshold is a dB higher or lower compared to other diodes but that could also be true for different batches of the same type. Doesn't really matter...
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