In various posts in this thread it is assumed that R52 controls the Decay time. I'm interested to know the thinking behind the DC voltage drop to set decay time? As Abes notes say this sets threshold?!turning the R52 Trimmer shows after a few turns a point, where the Voltage started to drop from this -0,82V DC, also my used Gainreduction SSL Clone 8027 Meters from Franks Fronpanels.de made a small move up and start at this point to rise, I set this Voltagedrop only minimal to about -0,80V DC as starting point on both Channels, then I set the Meter-Zere through adding/soldering a second 220 Ohm resistor in parallel over the R67 1K Ohm. It is also possible that you need another Value for R67 to get the "Zero" like a 300 Ohm .... You also can add here Pinholders and play around with other resistor, or a Trimmer.....
This was my statement. I wrote what I found when compared 555 vs inductor oscillator. My conclusion was 555 oscillator is too "stiff" and doesn't behave the same way as the discrete one.It is also suggested that R52 may "may not work correctly with 555 oscillator." I'm planing on building the ferrite core oscillator and see how this effect setup. Anyone have experience with chip VS ferrite?
Hi, I used an UTM 2546 600/10K. Ratio 1:4. Other Ratios did not work, wrong Range.What ratio transformers did you use to drive the sidechain?
Compressor sounds great. I have this for years. however never really understood how this sets ups.Hi, the "Pye Build Notes" are okay. Only the 0.25V DC Drop on R52 for setting the " Starting Threshold/Bias Point" was in my opinion to much, what I can remind setting up my Unit. Setting the VU Meter was also a little bit different. I wrote all things about the calibration and that should work fine using the same components, transformers/ratios, oszillator.... The PCBs work perfectly, nothing wrong. You should get a really fantastic sounding Compressor, one of the best ever designed ...
The general consensus is to remove TR11 to set unity gain. This removes the side chain from the audio path. This means that you can set the audio paths to unity.Here are a few detailed Photos of the unit. I used "standard" BC550/60 C's. I have soldered sockets to test more expensive transistor on TR 12, 16 and 18. But specially for TR11 it is necessary to remove TR11 for Calibration!
All important infos are in the Thread and in the instructions. It is a lot to read, I know.
The inductors look like Carnhill which would make sense as they are both British manufactures also supplied the likes of Neve. Potentially custom wound for PYE or off the shelf long discontinued.Don’t bother with the service manual. It doesn’t have any info regarding blocking oscillator inductor and AOT components. If you do decide to buy this paper, ask a seller if this manual actually has the info you need. If it does, I’m ready to split the cost.
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