Q for transient designer user (proto on the bench)

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zamproject

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Yes that's an option, I'll see if I invest in 8 rotary selector (21pos)
For the moment I use small knob on the 1U prototype, which are not that precise (as original probably)
The final device will be 2U with big knob, should help as angular precision get better as more big the knob is

As an update about this project, the proto is racked and in service in the studio since 2 months now, work perfect so far with no issue.
The aesthetic design is finished since weeks, so i suppose It's time now to order the 2U rack and panel.

I was tempted to add a feedback function for the sidechain (TD is forward topology) which offer some extreme behaviour. But I probably keep the idea for a single stereo unit later (have one SC pcb left), maybe with added SC EQ too, and mix function, which combined should somehow produce interesting envelop.

Cheers
Zam
 

tommia

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You could also add a switch for att en sus: normal vs one tenth of the range.
Who made the pcb's ?
 

zamproject

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That was one of the first mod in mind but half or 1/3 range , 1/10 is probably too much range reduction for what I do with it until now.
in fine I KISS it, like the original.

I use Aisler for the pcb manufacturing
 

zamproject

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Enclosure and front panel ordered.
Time to pick a PS, I'll probably go with Traco TMP 30515, so far the only easy to find SMPS with symmetrical current at the +/-15 (500mA)
I'll probably be on the edge for min load a the 5V rail (LED/relays), I'll see if it's an issue.

Hope I can seal everything next week 🙃

Cheers
Zam
 

zamproject

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Not finished yet, but receive the enclosure early this morning. Can't wait :)
I just mounted the front panel and side/rear enclosure (all the electronic still in the 1U rack just below)

Aesthetic is a very personal thing, but I like it this way, sober.
Basalt grey powder coating, black and white UV print.

TR515.JPG
 

zamproject

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Hope you get any spare pcb to sell..
Unfortunately no, I only order 3 (and used 2), and there is no plan for more or DIY release. This dynamic processor is in production by SPL, there is nothing original in my implementation, and I don't want to mess with anyone.

It was a fun project to study, pcb routing was also a funny and nice training with 40 opamp.
 

zamproject

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That really looks pro too! Congrats!
Tks tommia


I finished the rack enclosure last week with the ordered Traco SMPS , but without much test since.

Today I had a mix recall to do on the desk and peripherals (including the TD used in prototype form) for previous work done last fall requesting mix alternatives for live playback.

Now the unit have some audio cut-off, and intermittent motorboating.

Everything worked fine for 3 month with the linear PSU, I'll have to see if I made a mistake at rewiring or if the new smps make some trouble...
 

tommia

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That really sucks! If you go that far in a project , you don't want to investigate such a problem. Replace the powersupply with the one before. That's only 3 wires to do. Cut-off in low or high?
 

zamproject

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I'm overbusy right now for various reason, but I'll trouble shoot this asap`.
Unfortunately and despite the 2U rack, I have no room in the current mechanical integration to fit the linear PSU used in the 1U proto.
It's speculative for now as I don't find this SMPS block digram, but depending of the link between main rail (+5 logic) and the +/-15 audio, maybe the issue is the logic rail insufficiently loaded :unsure:

Cheers
Zam
 

zamproject

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I think it's solved...

I use 4 studer vca card with dif input and cross coupled output BUT at asym console insert.
My proto rack (studer standard 1u with 3 eurocard holder) have the IO including pin 1 (or pin 3 and sleeve in my case) directly connected to the card connector (no pin 1 to frame) but the vca card have a 100ohm at 0V return, with ref 0V for I/O at the inside of that.
In my final enclosure I first wire the pin1/sleeve at frame, ref being at the other side of the 100ohm, as psu main ref and safety ground.

I suppose the coss-coupled/sensing output don't like ?!?
Not sure if what I write is crystal clear, but I guess it's like the cross coupled output have 0V and -leg linked via 100ohm resistor, where 0ohm is preferred...

Cheers
Zam
 

zamproject

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Now I double check my rails

The +/- 15V drop below 12V when the 5V relay/logic is not loaded (on/off and link relay not energized)
The motor boating issue at audio seem solved since rewiring, but I'll like to fix this too for consistent rail supply...
I'll suppose I have to constantly load the 5V rail.
 

zamproject

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15ohm resistor added to 5V rail, to permanently load at least 10% but I'm not happy with that, to many power lost with heat.
For now the unit is closed and installed back in the rack, but I'll probably change the PSU later...
 

elskardio

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15ohm resistor added to 5V rail, to permanently load at least 10% but I'm not happy with that, to many power lost with heat.
For now the unit is closed and installed back in the rack, but I'll probably change the PSU later...
According to the Traco SMPS's specs, minimum load should be 10% of rated max current. The 5V is rated for 3000mA... so it should be loaded with at least 300mA for proper operation. Your 15ohm resistor gives a 333mA load... pretty close to the minimum ;)

Maybe you could parallel multiple resistors to distribute the heat.
 

zamproject

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Yes that's my math, that's why I put a 15ohm, I also pick a 10ohm yesterday at my local electronic shop (don't have 5W resistor in stock). But I wire the 15ohm as the 10ohm will disip more... 2.5W.
330mA in the worst case with all relay off, meaning the unit is not in use (all bypass)

I don't care that much about heat, there is room in the enclosure, I'm more concerned about lost power...

I'm not that happy with this traco...
The datasheet ask for minimum load at each rail but only to meet spec (not to work), which I don't care for the 5V (only relay and leds)
+/-15 are correctly loaded (about 250/300mA)
But the load on the primary 5V rail influence the voltage of the 2 others (+/-15)
I don't expect this...

I'll see if I change for linear one, or 2 separated SMPS with a better matching regarding load, or use a simple dual and change all my relays to 12V spec (or add series resistor).
Relays are only bypass and link, not the kind of setting you change wile processing audio. So energizing them from audio rail should not be an issue.
 

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