PYE Compressor/Limiter Thread *boards shipping* BOM up!

[bruno2000]

I calculated the r values for a 2 dB/step stepped attenuator with a total value of 10k and a max attn of 40dB, and am going to try and put them together this weekend.  Now if the middle of the attn is 20 dB down for each section, and the overall gain of the comp with both pots up full is about 30dB, where does the extra 10dB come from to make it unity  gain?
Thanks!
Best,
Bruno2000

 

[bruno2000]

I've made performance improvement by replacing the 50 mH choke in the BOM with one I wound myself.  MUCH lower DCR, less PS sag on the outputs.  Feeds 600 ohm load OK now.  Running the rail at 16V like the original, but looking to add a 10dB boost circuit on the output with more swing available.
No change in the knee positions  That's still a mystery.
Best,
Bruno2000

 

[bruno2000]

Forgot to say that I also made the dual 2 dB / step 40 dB attn, and reverse on one shaft.  It works GREAT.  PM is you want the values. 
Best,
Bruno2000

 

[bruno2000]

For those of you building this piece, I have found that the output circuit is MUCH more stable if you use a choke (L1) with a low DCR.  I bought the one on the BOM, and it measured about 170r.  I wound a couple myself on Ferrite cores that have a DCR of about 5r.  Just my $0.02 YMMV.
Best,
Bruno2000

 

[desol]

Good stuff Bruno and thanks...

 

[Travis1000]

Hey all, I've finally gotten to put the time in and get this thing all wired up. One question I can't seem to find the answer to: there appear to be trace jumpers on the board near TR16, R59, and R61.  As well as one near the edge of the board and R42. There are also some on the switch board. Should I be jumping these to something?

So far, I have gotten audio to pass in one of my board and the other passes audio but with a lot of hash, it's quite noisy still.

I am still figuring out how to tune the chopper, I'm new to the world of oscilloscopes so any info on what I am looking for on the scope for a properly tuned chopper would be much appreciated. Thanks!

 

[mdainsd]

The only trace jumpers that may be needed are at the VRs. The footprint allows several different VRs to be used. The center connection in each case has three different holes for different VRs. I f you use VRs that dont have all three pins inline you need to jump the center holes together. What I did is just fold the center lead of the VR over on the backside of the board and solder it to all three pads.

Scopes: see if you can find tutorials on youtube. The ground connection on the probe is important, it needs to be short and connected to B+ (common) close to where you are probing.

 

[bruno2000]

The BOM says you can use a 5k1 resistor for R42.  Put in trimmers both set to 5k1 if you want good tracking at the knee when linked.......  Adjust the side that "droops".
Best,
Bruno2000

 

[Quantum J Audio]

I have both sides of the compressor up and running, passing audio and compressing.  They sound great, just waiting for my scope to arrive before I properly calibrate the chopper.  but so far really pleased.

I have the same meter problem that has been discussed in earlier posts.  I meter 4db of gain reduction when no audio is being passed.  Meter adjust makes small changes, but not enough to zero.  Interestingly when I take the IC out of the circuit I meter 8db of gain reduction.  Has anyone got any further thoughts on this issue? 

I know some of you have been tweaking various trimmers and experimenting.  Is anyone getting close to a definitive setup.  I have everything set up and built to the sr1200 build guide. 

I have grounded in the following way to the star ground.

Pin one from input and output XLR's
Ground from output on PCB
Pins 2 , 6 and 7 from CMLI-15/15B2
IEC earth

Your question about the switches and which side of the board they mount to. Comparing the silkscreen on the Collective Cases enclosure with the image of the 3.14 PWB...the switches would need to be mounted on the backside of the PWB with the silkscreen, header and other components facing away from the front panel for everything to line up (control name wise).

But...everything should be verified with the schematic and an ohm meter.

This is wrong, to be fair It does say to check with an ohm meter and schematic.  However I spent ages triple checking.  To clarify for anyone about to build this, the components face the front panel and the Lorlin switches should be soldered on the same side as components and silk screen.

 

[bruno2000]

I have the same meter problem that has been discussed in earlier posts.  I meter 4db of gain reduction when no audio is being passed.  Meter adjust makes small changes, but not enough to zero.  Interestingly when I take the IC out of the circuit I meter 8db of gain reduction.  Has anyone got any further thoughts on this issue? 

I know some of you have been tweaking various trimmers and experimenting.  Is anyone getting close to a definitive setup.  I have everything set up and built to the sr1200 build guide. 

Your question about the switches and which side of the board they mount to. Comparing the silkscreen on the Collective Cases enclosure with the image of the 3.14 PWB...the switches would need to be mounted on the backside of the PWB with the silkscreen, header and other components facing away from the front panel for everything to line up (control name wise).

But...everything should be verified with the schematic and an ohm meter.

This is wrong, to be fair It does say to check with an ohm meter and schematic.  However I spent ages triple checking.  To clarify for anyone about to build this, the components face the front panel and the Lorlin switches should be soldered on the same side as components and silk screen.

When you say 4dB and 8dB of meter reduction, what meter are you using?  I'm using a standard 1 mA meter and am going to have to make a custom scale since the gain reduction that I measure with my audio test set does not correspond to ANY commercial scale I have seen so far. 

+1 for the Lorlin switches, although I decided to go with the original switch configuration, and did not use the switch board.

Best,
Bruno2000

 

[Quantum J Audio]

When you say 4dB and 8dB of meter reduction, what meter are you using?  I'm using a standard 1 mA meter and am going to have to make a custom scale since the gain reduction that I measure with my audio test set does not correspond to ANY commercial scale I have seen so far. 

I'm using the hairball 1mA meter.  I mean to say that powered up but with no signal the meter sits at 4db on the scale.  I noticed in the youtube prototype video it is sitting not on, but pretty close to zero. 

Where does your meter sit on power up with no signal? 

 

[bruno2000]

When you say 4dB and 8dB of meter reduction, what meter are you using?  I'm using a standard 1 mA meter and am going to have to make a custom scale since the gain reduction that I measure with my audio test set does not correspond to ANY commercial scale I have seen so far. 

I'm using the hairball 1mA meter.  I mean to say that powered up but with no signal the meter sits at 4db on the scale.  I noticed in the youtube prototype video it is sitting not on, but pretty close to zero. 

Where does your meter sit on power up with no signal?

Even though my meters are 1 mA full scale, the existing linear scale on the meters  goes from "0" to "4".  With no signal, my meters read 0.1, just barely above "0".  I made a spreadsheet with overall gain reduction, with compensation for loss through the circuit.  I'll post my scale when I get it finished.

 

[Quantum J Audio]

Thanks Bruno, so it looks like I need to work out an issue somewhere in my meter circuit. 

For anyone looking for a budget scope I have Just got the DPScope 2.  It is 2 channel USB and also can be used to show readings as as DMM. 

 

[shot]

This thing pushed me into buying (my first) scope also!
I've ordered Hantek 6022BE (yeah - the cheap one!)

I have the boards all stuffed, meters and transformers ready but I'm still waiting on the scope and enclosure.

Keeping my fingers crossed and trying not to be impatient...

 

[tommia]

is an 100k resistor between ground and the bases of TR15 & TR 18 needed? It is in the original schematic but not on the pcb?


For those to trace problems:
First see if it passes audio if so the circuit from tr1 trough TR10 is OK.
second if the meter moves when you connect audio than the circuit  from TR12 trough TR18 on the main board is working.
If you can't find TR11 in Europe order MMBT3640 at farnell.


Calibration of the meter will follow

 

[mdainsd]

Somewhere I posted that after I looked at the switch board for the 50th time and played with it that they are OK as is.

I messed with R52 until the meter was indicating the lowest with no audio input. Mine sits with the needle just off of zero with no signal. R42 is what I used for meter calibration, not zero. As Ive said mine always has chopping pulses present, even with no signal. they are just tips of very narrow pulses but they are there.

Mines been running just fine in the studio for several months now.

 

[Biasrocks]

Ok, Abe is mia.

No mention of the Pye kit or tech support on his website,  there is a fully built version you can buy for $1,700.

It seems Abe managed to get his product up and running with help from the fine folks on this forum and then chose to abandon the everyone who bought into his apparently flawed product.   

Sad.   

I want to thank the people in the GDIY community who are willing and able to get help the pye builders up and running.

You guys rock!

Mark

 

[Quantum J Audio]

It seems Abe managed to get his product up and running with help from the fine folks on this forum and then chose to abandon the everyone who bought into his apparently flawed product.   

I want to thank the people in the GDIY community who are willing and able to get help the pye builders up and running.

You guys rock!

Mark

I've heard Abe is MIA but I don't think this build is flawed.  There aren't any mistakes on the board that will stop proper operation and the information required to get an operational unit is all within this thread. 

 

[mdainsd]

I think I'd agree with that. The last version of the boards go together just fine, with only the slightest modification.

There are some other builds on this forum that seem like real horror shows in comparison.

If you have decent skills you should be able to get these up and running.

If you love DIYing then you will continue to refine the tuning of these mainly through time with a scope and meter and a handful of transformers.

Who knows what happened to Abe, probably circumstances beyond his control.

I consider myself lucky to have purchased a pair of these boards (wish Id bought four).

Ive turned down $4K for my unit. What would I replace it with?

 

[bruno2000]

Ok, Abe is mia.

No mention of the Pye kit or tech support on his website,  there is a fully built version you can buy for $1,700.

It seems Abe managed to get his product up and running with help from the fine folks on this forum and then chose to abandon the everyone who bought into his apparently flawed product.   

Sad.   

I want to thank the people in the GDIY community who are willing and able to get help the pye builders up and running.

You guys rock!

Mark

There are no flaws in the board, but some in the BOM.  YMMV.
Best,
Bruno2000