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[Build Thread] Oakley Sound SRE330
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2  Next [all]
Author [Build Thread] Oakley Sound SRE330
Bodo1967
Hi everyone,

since I am currently in the process of builing the SRE330 and there's no build thread yet I thought we might as well have one.

I bought the kit consisting of three PCBs, the pot brackets and power jack, plus a Yamaha PA-20 off German Ebay, and started the usual way.
That's how the PCBs look:



I first used what I had at home anyway, and then ordered remaining parts (some of which are still on their way).

The RPSU board in an early stage:



And the IO board in a similarly early stage:



The main board - following Tony's instructions, the pot brackets are not yet soldered.



And an overview:



I use sockets for all ICs.

The case will be somewhat tricky: I didn't find an appropriate case over here, except for one by Adam Hall, which is available only in black.

I thus decided to create the front panel myself (the Schaeffer ones are of excellent quality, but also really pricey) from anodized aluminum (which I cut to measure yesterday), using the original layout by Oakley, but converting it to colorless with black lines and lettering.

The case will be made from a Thoman rack tray. I'll convert this into a real case with some wood and sheet aluminum (pictures will follow).

Here's a detail of the tray - it had a slight transport damage which I could easily fix myself using my bench vise and some pliers. No big deal.



The pictures are almost 2 weeks old and there's much more components on the PCBs now, as the Musikding packet arrived in the meantime grin. I'll hopefully continue on the weekend and take a few pictures, including some of the case design and building process.
maltemark
Good to have a thread started on this one. Similarly, ive also received a kit, but haven't got as far yet. Awaiting the holidays eagerly.
yan6
I'm wondering if anyone has some advice yet on the ribbon connector between the main board and the input board. The main pcb has a keyway on the silkscreen, but the input board doesn't.
Bodo1967
yan6 wrote:
I'm wondering if anyone has some advice yet on the ribbon connector between the main board and the input board. The main pcb has a keyway on the silkscreen, but the input board doesn't.


The orientation is clearly visible in the build guide:



Copyright disclaimer: This picture is not by me but was taken from the build guide linked above.
@Synthbuilder/Oakley/Tony: I hope that's OK with you - if not, please pm me and I'll remove the picture from this post.
Pav
Hi, Just to say im working on the SRE too and I'm close to completing the main board...having completed a session soldering the ic sockets. I've gone for the case suggested by Tony ..but I'm dreading the drilling fearing I'll screw up an expensive item.

I had two slapdash moments in the build... Despite thinking I was carefull..the worst was placing a tiny 1nf cap in the ic socket holes. Instead of adjacent hmmm.....

Second was a purchasing goof on the 50k Bourn trimmer..it was a P variant instead of the F variant Tony suggested. The pin positions are different so needed some bending to fit and as they were offset ..the visual symmetry of the two rows of trimmers is gone. I hope the feng shuey is not disrupted too much.

Best of luck for your builds.
Bodo1967
There's some progress with the SRE330.

More or less all of the electronic components are now on the PCBs - except about 80 or so 100 nF caps, which are on their way to me. And the ICs are not in their sockets yet.

Anyway, here's an impression of how the mainboard looks now:



Box connectors on the mainboard and the I/O board (hope everything will work fine althought they are black and not white cool hihi :





And the jacks that will make the connection to the outer world grin.



The last few electronic parts will hopefully arrive soon, and I'll show most case construction from a rack tray, some sheet aluminum and a bit of wood hihi soon grin. Most of it is prepared so far, but I caught a bad cold recently that made me stop all DIY activities for about 2 weeks confused . I had actually hoped to get most of it done between Xmas and New Years's Eve, but what the heck... Dead Banana
Synthbuilder
yan6 wrote:
I'm wondering if anyone has some advice yet on the ribbon connector between the main board and the input board. The main pcb has a keyway on the silkscreen, but the input board doesn't.

Probably a bit late - but pin 1 is a square pad on the PCB. On the box header pin 1 should be shown by a little triangle shape on the plastic of the header. Just line up the triangle with the square pad when the header is inserted into the board.

Tony
Synthbuilder
Bodo1967 wrote:



I see you've fitted the much larger 7809 instead of 78L09 regulators. They look like they're fitted the wrong way around. So the input pin is connected to where the output pin should be.

Tony
Bodo1967
Synthbuilder wrote:
I see you've fitted the much larger 7809 instead of 78L09 regulators. They look like they're fitted the wrong way around. So the input pin is connected to where the output pin should be.


Oh woah , thanks. So I take it the pin order is not IN - COMMON - OUT from left to right with the small ones if you look at the flat side seriously, i just don't get it ? I admit I didn't check this since it didn't occur to me they might have different pinouts Dead Banana .

I simply used the 'big' ones because I had them lying around anyway.

Edit: Just double checked it, and (of course) you're right. I'll put them in the other way round. Thanks anyway!

Edit 2: Nope. I removed them today and will replace them with 78L09, which I ordered today.
Bodo1967
The 78L09 have arrived in the meantime, and I soldered them in on the weekend. Still waiting for the 100 nF caps though Dead Banana .

Anyway, there's some serious progress with the case. That's a bit tricky because I have to provide some kind of support on which I can attach the frontplate. The easiest way (considering the tools I have at hand) is using wood.

It's rather easy on the left side:



But on the right side I needed to cut out a bit to fit the switch while still preserving some space for the holder screws:



Then it was time to prepare the front panel - all holes are drilled, but there's some final work to do:

- saw out the rectangular hole for the on/off switch
- properly shape the rack mounting holes at the edges
- increase the diameter of the holes for attaching the front panel to the wood blocks (now only 2 mm, needs 3.5 mm)

That's a first impression of the front panel. Of course, this is just a print on ordinary paper attached to it as a drill template.

yan6
I finally received the switches from overseas and was able to get this fired up tonight. It passed audio straight away and most of the calibration. I have one issue that i hope Tony can weigh in on.

At Pin 6 of u32 im reading a clock of 860khz and obviously the clk1 pot doesnt make any significant change. I must have a wrong part in somewhere. Any advice where to start checking.

All the other calibrations worked out well except the null1 since the wave was so fast i could accurately see it.

One point of interest from the photos below, i soldered onto the pot brackets some pieces of cut threaded strip to mount the panel to the pcb.





Synthbuilder
yan6 wrote:
At Pin 6 of u32 im reading a clock of 860khz and obviously the clk1 pot doesnt make any significant change. I must have a wrong part in somewhere. Any advice where to start checking.

In the first instance it'll worth swapping U33 with U39 and see if the problem moves with the IC. If it does you probably have a bad 3101 chip.

If nothing changes then check C103 is a 100pF cap. As an aside I notice you've used what looks like ceramic plate capacitors for all your ceramic capacitors. Generally, I don't recommend these as they are not really that good a part. I don't think they'll be too much an issue in this project but normally I would recommend C0G (low-K) ceramic capacitors as they perform much better - greater accuracy, no microphony and a lot more stable with temperature and age.

Also check that both Q8 and Q9 are both BC550 or BC549.

And watch that bolt that's holding the toroid isn't going to be touching the top panel when the case is put together. Otherwise... Dead Banana

Tony
yan6
Thanks Tony, so I swapped the 100pf, C103, C138, C166 & C189 to COG type caps with no effect (the wave was a bit cleaner on the edges of the working clocks, but clk1 was still really high).

I also swapped U33 and U39 and the issue stays with clk1. I also tried swapping U32 with U38 no change there either.

And finally confirmed that Q8 & Q9 are BC550's
Synthbuilder
OK, that's ruled out the more obvious faults. Now it's time to get the scope out and compare a working channel with the faulty one. Set modulation depths to zero. Have a look at the middle (the base) pins of Q8 and Q10. They should be about the same voltage - around +3.5V, although the CLK1 and CLK2 trimmers do affect things a bit. If the base of Q8 is way out, like +13V, then suspect the circuitry around U18 and the components directly to the left of it.

If the two bases are near enough the same voltage then the problem is probably around U33 and its associating components. Check all values and soldering around the components.

Tony
yan6
Okay looking around a bit near u18 so far i dont spot anything out of place. I have noticed that the voltage on pin 1 of u18 is 15v while pin 1 of u22 is 2.5v. I also notice that the recext pin 1, 2 and 3 are very different between u33 and u39.

Below are pins 7, 6 and 5 of u39 and then the same order but for u33










U33 now











Synthbuilder
My fault. Sorry. eek!

You have R104 and R102 swapped. R102 should be 56K and R104 should be 330K. The Builder's Guide version 2.5 is wrong. I will correct this immediately.

The schematic is correct.

What's puzzling is that no one else has spotted this before. Perhaps they've built from the schematic?

Tony
yan6
Rockin' Banana! that sounds like an easy fix ill give a shot tonight
Synthbuilder
yan6 wrote:
Rockin' Banana! that sounds like an easy fix ill give a shot tonight


Hope so.

And thank you for posting pictures I wouldn't have spotted it otherwise. thumbs up

Tony
Bodo1967
Synthbuilder wrote:
You have R104 and R102 swapped. R102 should be 56K and R104 should be 330K. The Builder's Guide version 2.5 is wrong.


Oh-oh, that'll be most certainly the case in mine as well. I used the BOM included in the builder's guide. Thanks for posting that, Tony - swapping them isn't a big deal.

Edit: Yep. I'll swap them during the next soldering session...

Synthbuilder wrote:
What's puzzling is that no one else has spotted this before. Perhaps they've built from the schematic?


Nah, but since I'm still waiting for the 100 nF caps to arrive Dead Banana I simply didn't proceed far enough to even think about testing the unit yet confused .
Bodo1967
Bodo1967 wrote:
Synthbuilder wrote:
You have R104 and R102 swapped.

I'll swap them during the next soldering session...


I did that in the meantime, no big deal.

And I built the LED holders, using perfboard since I had no stripboard at hand:



I just bent the LED legs and soldered them to the, erm, modified PCB connectors I used at the bottom part of the PCB:



By now, the LED panels are mounted on the main PCB.





There's also quite some progress with the front panel (as in, it is finished) and the back.

... and I'm still waiting for the *censored* caps, of which now a replacement shipment is on the way meh ... Dead Banana
Bodo1967
Bodo1967 wrote:
... and I'm still waiting for the *censored* caps, of which now a replacement shipment is on the way meh ... Dead Banana


The caps finally arrived on Saturday so I could proceed, i.e. I soldered the caps and inserted the ICs.



The I/O board and the jack for the Yamaha PSU are mounted to the back wall using small aluminum panels:





The back wall is in place:



Time to drill the holes and mount the RPSU board (the attached cable is for grounding the case):



First power up test - voltages are reasonable; I measured +15.2 and -15.6 V, respectively. Nothing got hot either. The relay clicked rather quickly (considerably less than a second, it was more like 0.2 seconds or so) upon switching the unit on, and quickly as well after switching it off again. And nothing got hot, neither right away nor after 10 or 15 minutes.



Finally, I connected the main board.



The level LEDs behaved (almost) as intended and expected - they all went on briefly, and then off again successively. "Almost": except for the red one, that is. I suppose this coincides with the very "quick" behavior of the relay I used, so I do not worry too much about it right now. The power LED stays on as it should.

Again, nothing got hot when powering it up, neither right away nor after a couple of minutes. I checked every single IC.

I guess that means testing and calibrating is up next grin.
Pav
I had similar results on power up test and the faster than expected relay, so sounds ok.
Bodo1967
Pav wrote:
I had similar results on power up test and the faster than expected relay, so sounds ok.


Thanks for your feedback & information thumbs up !
Synthbuilder
Bodo1967 wrote:
The relay clicked rather quickly (considerably less than a second, it was more like 0.2 seconds or so) upon switching the unit on, and quickly as well after switching it off again.


Yes that's fine. The important thing is that it does actually click and doesn't take more than one second.

What's up with the red LED? Did it come on at all or does it stay on longer than the others? Both my builds have the red LED coming on and turning off before the others - which is what I would expect to happen. But then exact power up sequences can be difficult to predict.

Tony
Bodo1967
Synthbuilder wrote:
What's up with the red LED? Did it come on at all or does it stay on longer than the others?


It didn't come on at all, whrereas the other three (two yellow and a green) behaved as described. I think I'll just continue testing and calibrating the unit, and if the red LED then works properly as a peak indicator, I'm fine with that.

BTW, I have two tiny remarks concerning the user manual - both on page 11:

1) Right at the beginning it says "There are sixteen trimmers". But there are eighteen cool :

4 * CLK; 4 * OFF; 4 * NULL; in total 4 * FRQ & LVL; plus FAST and SLOW.

2) In section CLK 4 it accidentally reads "Adjust CLK 1...". Just a copy & paste error, I suppose.
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