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Post by brucew268 on May 25, 2021 13:17:01 GMT
Some build pics. I'd read a few complaints of all panels and screws not fitting on Modushop Dissipante, so needing modification. I did a quick assembly to check and found that if one assembles all but the top cover keeping the screws loose, it all fits fine. Then tighten the screws.  Gianluca at Modushop has these graphics from previous orders. I wanted the 686 to be a bit smaller than Karl's (@5x5cm) so had him scale it down to @3x3cm. The power button will go above the 686 and centered on the panel. Looks rather sharp I think and slightly understated.
 The modushop heatsink fins are a wavy design which gives them a bit more surface area and meant to be 20% greater dissipation. So 40mm x 165mm should do well in driving 3ohm hungry Maganepan .7's. The base is 0.10" or 2.54mm and with the weight of the sink and the thinness of the fins, it might as well be sharp... it can cut you if you don't respect it.
 More in next post.
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Post by brucew268 on May 25, 2021 13:19:59 GMT
Laid out the components to decide on placement.
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Post by brucew268 on May 25, 2021 13:22:41 GMT
I did both a paper mock up and physical placements to determine the layout on the back panel. There seems to be enough clearance for the power boards, transformer, and the wires coming off the IEC inlet. It should also be easier to adjust or work on the Intelligent Soft Start (ISS) to center it above the IEC inlet. This should make for better separation between signal wires, toward the outside, and power wires toward the centre.
For drilling I used temporary spray adhesive to mount the paper template, above, to the rear panel. Then centre punch each hole and start with 3.2mm drills.
Since the speaker wires will go out to the side anyway, I put them closer to the outside and arranged vertically. Most amps I see have them horizontal, but that doesn't make as much sense to me based where the speaker cable will route to the speakers. The holes are 12mm with an anti-rotate slot, so used a spiral step drill to 12mm. Then I used a dremel cutting disc and steady hand to do the slots on the front bottom edge of the holes.
XLR inputs were done with a TCT 24mm hole saw, which fits Neutrik. But I'll probably mount EIZZ XLR which only needs 22mm. Fortunately the fixing screws have the same placement for both. For the hole saw I went with Starrett instead of the chinese no names that abound, but it did worse than the chinese ones I used on my preamp. So that extra money wasn't well spent. I had considered a spiral step bit instead of a hole saw but thought that would be too much waste. When I do the XLR's on my preamp, I'll probably revert to an M35 spiral step drill at 22mm.
I sanded one of the mounting holes bare on the inside of each XLR to attach the chassis ground of the balanced input.
The IEC cutout was done with a dremel and cutoff discs. Anodised aluminium goes through them quickly so good that they come in stacks. Then i finished to the actual dimensions with a mill file.
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Post by brucew268 on May 25, 2021 14:06:23 GMT
The back needs a little cleanup, and it seems that 99% alcohol is breaking down the black anodisation? Or maybe I just need to use a cleaner cloth. Will see. The speaker terminals are CMC 858-S-CU Pure Copper. I wanted solder connections but could only find ones with grub screws. They still should serve well as solder cups. The XLR's are still Neutrik but will be changed out to EIZZ before finishing.
A test hookup of the Intelligent Soft Start to IEC and power switch.
Notice the 10mm square stock that reinforces the top and bottom panels by mounting to the rear panel. The 3mm bottom panel seems to handle the weight of the 800VA transformer without complaint but I felt better about it this way.
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Post by brucew268 on May 25, 2021 14:12:04 GMT
Power is all wired up and working. I played with a couple routings from the power switch to ISS module. We'll see how this does.
The transformer is O-core from James transformer. I went to attach Tom C's power wiring harness between power supplies and amplifier boards, and then noticed that they are not long enough for where I'd drilled and mounted the right channel board! I had to take apart, drill, and tap one more hole to the right and now is fine.
If using the press-on JST VL connectors, having precrimped by the proper tool makes for better connection between wire and connector. However, I wonder if the press-on connectors make as serious a connection as the screw terminal blocks, let alone soldered connections. I'll build and use as spec'd and later consider whether to bother with soldered connections to the amplifier boards.
Just connections to and from the Modulus board now. Hopefully will have sound by the end of the week.
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Post by antonio on May 26, 2021 2:18:47 GMT
Looks to me like another nice build there Bruce, well done. I have to say I am very impressed at the neatness of everyone's build's on this forum, must go show you are all very skillful, or you must really take your time, maybe a bit of both.  |
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Bigman80
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Post by Bigman80 on May 26, 2021 7:20:04 GMT
Yes, very tidy.
You've not much left to do!
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bigbird
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Post by bigbird on May 26, 2021 23:28:28 GMT
Looking good. Glad to see my hours of designing the logo could be put to good use again .
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Post by brucew268 on May 27, 2021 7:02:18 GMT
Looking good. Glad to see my hours of designing the logo could be put to good use again . I was wondering if the 686 logo was yours since it wasn't included in what Tom sent to me. The main Neurochrome logo was his, right, but perhaps you changed the first bit to blue? |
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bigbird
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Post by bigbird on May 27, 2021 7:20:23 GMT
Looking good. Glad to see my hours of designing the logo could be put to good use again . I was wondering if the 686 logo was yours since it wasn't included in what Tom sent to me. The main Neurochrome logo was his, right, but perhaps you changed the first bit to blue? Yeah so I designed the Modulus 686 part and then changed his official logo to blue and silver and sent them off to gianluca for printing. Looks great against the black doesn’t it? |
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Post by antonio on May 27, 2021 14:59:58 GMT
Certainly better than Pink  |
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Post by brucew268 on May 27, 2021 16:03:54 GMT
I was wondering if the 686 logo was yours since it wasn't included in what Tom sent to me. The main Neurochrome logo was his, right, but perhaps you changed the first bit to blue? Yeah so I designed the Modulus 686 part and then changed his official logo to blue and silver and sent them off to gianluca for printing. Looks great against the black doesn’t it? It does, though I changed the silver to white for whatever reason. It looked white in your photos and I decided to go with blue and white since it was in my head. |
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Post by brucew268 on May 28, 2021 13:30:11 GMT
The back needs a little cleanup, and it seems that 99% alcohol is breaking down the black anodisation? Or maybe I just need to use a cleaner cloth.
Actually, it was traces of thermal grease that had contaminated the cloth and was sticking in the panel grain. It took a couple passes with Goo Gone and then a couple passes with alchohol and a clean bit of cloth each time before the panel looked right again. |
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Post by brucew268 on May 28, 2021 13:31:49 GMT
Has anyone done a listening comparison between different speaker hookup wire, and/or between press-fit connectors and soldered?
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Bigman80
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Post by Bigman80 on May 28, 2021 13:34:53 GMT
Has anyone done a listening comparison between different speaker hookup wire, and/or between press-fit connectors and soldered? Soldered connection with OCC copper wire was my choice |
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optical
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Post by optical on May 28, 2021 13:55:59 GMT
Has anyone done a listening comparison between different speaker hookup wire, and/or between press-fit connectors and soldered? Soldered connection with OCC copper wire was my choice I'll be pressing ahead doing OCC wire and soldered connections (as opposed to my now spade connectors) in the not so distant future also, so will be interested to see the results Bruce. Nice build, very nice. |
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Post by antonio on May 28, 2021 23:53:11 GMT
OCC - Don't Spoil the Ship for a Ha'peth of Tar
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Deleted
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Post by Deleted on May 29, 2021 8:18:25 GMT
Tom didn’t think desoldering the connections was a good idea when I spoke to him about it.
I redid the cables with OCC and JST connectors.
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Bigman80
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Post by Bigman80 on May 29, 2021 8:39:38 GMT
Tom didn’t think desoldering the connections was a good idea when I spoke to him about it. I redid the cables with OCC and JST connectors. Yes, good point. I'd use caution in that regard. |
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Post by brucew268 on May 29, 2021 12:53:26 GMT
Yeah, I'm not real happy with the arrangement in a couple ways right now and have some choices:
I asked Tom why he used the JST press on connectors rather than screw cage terminal blocks or solder points. His answer was, because most amplifier module manufacturers do it that way. I note his PDF intructions say that if one wants to solder, they should do so to the bottom of the board rather than removing the JST connectors because one is likely to damage the board trying to remove the JST's. Of course I've wondered if I couldn't just cut the JST with strong wire cutters and then desolder the stubs. But I think I'll leave them as is for now.
But on the Input connection: that low level signal input would seem more sensitive to soldering vs other connections, so I thought I'd solder to the bottom of the board for that. I have a half metre pair of old Harmonic Technology Truth Link IC's that are OCC and very good but surplus to needs. So I cannibalised them. But they're a bit thick and stiff, and each conductor is actually three individually teflon-coated wires, so is a pain to work with in multiple ways!
This is the left channel which came together decently but I'm not real comfortable with it -- a stiff cable under a little tension and soldered up against terminal pins. I wonder how long that will last?
This is the right channel, not soldered yet, just playing with the dressing. As shown, I could keep the R & L cables the same length (0.5M) but then am dealing with unwieldy and unsightly cable. And it's ranging across the inside looking for stray fields to pick up or reject, though it's shielded. It might be better to go much shorter and straighter on the right channel?
So:
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Post by firebottle on May 29, 2021 17:27:34 GMT
Stick with the cable you have, use equal lengths and cable tie and dress so there is no movement, sorted.
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Post by brucew268 on May 30, 2021 17:53:44 GMT
Life is a series of compromises and one just has to decide which ones they are happy to live with and which they aren't. I ended up staying with the Harmonic Tech OCC input cables but using the screw cage Amphenol plugs. I wasn't happy with connections having just a wire laid up alongside a through-pin and soldered to it but under tension. Oh, I did remove the outer cable jacket in a few places where there was a curve through free space for less tension and weight. There is still a silk weave over the copper screen weave, and there is PVC wherever the cable could be near to metal. I could have disassembled and removed the heat sink mounting brackets then drilled and filed a hole in a new place for a better zip tie location, but I'm just a bit impatient at this stage, not having listened to music in the lounge since October. And I don't want to cock things up by trying to destroy and remove the Amphenol connectors without adverse effects to the PCB and circuit. So this is what I've got and running a couple simple tests, then hopefully music tomorrow!
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Post by antonio on May 30, 2021 23:49:08 GMT
Looks tidy to my untrained eyes |
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bigbird
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Post by bigbird on May 30, 2021 23:57:36 GMT
Looks tidy to me too.
Come on... how does it sound?
You may need some clean underpants , that’s all I will say
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Bigman80
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Post by Bigman80 on May 31, 2021 7:13:01 GMT
Put the lid on, plug it in and have a listen.
Looks absolutely fine!
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Post by brucew268 on May 31, 2021 17:10:05 GMT
We have sound in the lounge! Did the rec'd output voltage test using a sine wave and all was fine... once I remembered to set the multi-meter to AC! Sounds pretty good. I've not done critical listening at volume yet and figured the caps would be happy with a few hours on them prior to serious listening... but I do notice that there is better control of the speakers at low volumes than my previous amp. There is more body and nuance even at low levels but not in a spotlit HiFi "look at me" way. It just flows out. But I've not really done a proper audition. A few more pics.
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Bigman80
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Post by Bigman80 on May 31, 2021 17:18:32 GMT
We have sound in the lounge! Did the rec'd output voltage test using a sine wave and all was fine... once I remembered to set the multi-meter to AC! Sounds pretty good. I've not done critical listening at volume yet and figured the caps would be happy with a few hours on them prior to serious listening... but I do notice that there is better control of the speakers at low volumes than my previous amp. There is more body and nuance even at low levels but not in a spotlit HiFi "look at me" way. It just flows out. But I've not really done a proper audition. A few more pics.
Well done, Bruce. Looks a proper job and you now own an amplifier I rate really highly. Keep us informed of your thoughts as you get some hours on it👍 |
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Post by sq225917 on May 31, 2021 21:10:28 GMT
Nice , another one completed
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Post by brucew268 on Jun 5, 2021 17:21:15 GMT
BTW: I changed out the cover screws on the Dissipante chassis. They came with allen flanged head but those seemed a little more prone to stripping than I like, and allen heads are a pain to extract when stripped. So I replaced with allen button head screws which have a deeper allen socket which I like better.
Flanged vs button head M3 x 8mm
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Post by brucew268 on Jun 5, 2021 17:27:39 GMT
At volume I'm not getting quite the breathing 3D rendering of instruments I'd like, so am planning to change the signal input and output connections on the amp board to soldered and remove the plug modules. I might as well subsitute OCC for the speaker output while I'm at it, so ordering that for next weekend's project. This of course makes future disassembly more work, but if this is the solution it will be well worth it. BTW: I found a video with a hack for desoldering multipin components, so will give that a try next weekend.
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