Post by colinf on Apr 12, 2021 19:01:49 GMT 12
I find it easier to use very slow speed if deburring with a drill bit.
AMR-iFi R&D
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Post by Owen Y on Apr 13, 2021 13:55:32 GMT 12
It's nice to have one of these hand-deburring tools in the drawer:
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Post by sadface on Apr 15, 2021 22:16:42 GMT 12
That's exactly what I have purchased in like of my booboos with the 13mm drill bit!
Progress has been pretty good this week. It always amazing me how long wiring can take to do nicely.
The mains wiring is done. Here is the main run from the IEC socket to the fuse to the power switch. I'm using Jaycar mains rated wire. Twisted as tight as I can and then doubled insulated in clear 600v heatshrink. I'm pretty big on double insulation, especially on the mains side as I don't like risks.
The loom is a bit slack right now but once testing is passed and the chassis painted I will use some cable mounts to tidy things up more.
Here' is my device for splitting the mains to the 2 transformers after the power switch. Same treatment for the wiring on the transformers; pairs twisted as tight as possible and then covered with clear heatshrink. It has the added benefit of keeping the twisting tight as well as the extra insulation.
Here's a shot of the wiring from the transformers to the rectifier boards.
Power swtich dangling out the front waiting for some wood to mount into. Here's the output wiring all sorted for now. I think I will want to move the speaker protection board away from the back panel after testing as its a bit crowded back here right now.
All that remains is the input wiring and the speaker protection driver wiring. The beginning of the end is in sight!
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Post by sadface on Apr 18, 2021 17:45:31 GMT 12
G'day Guys,
The first draft is completed!
Completed input wiring.
I'm not entirely happy with how the input wiring worked out. I couldn't get the braided sleeve that I wanted to use to fit nicely so I went with plain heat shrink for now.
This is simply a first draft at this stage. I want to verify everything works properly before worrying any further about how I might do things nicer. Things like the yellow ground wires from the PSU boards to the chassis earth will be routed nicer after verification.
For now I am pretty stoked to be at this stage.
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Post by colinf on Apr 18, 2021 18:53:00 GMT 12
Nice, remember to add some small 0.1uF caps from the rca socket grounds to the case next to them for RF continuity.
AMR-iFi R&D
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Post by sadface on Apr 25, 2021 20:44:59 GMT 12
G'day Guys, I had some time today so I fired up the power supplies as the first test.
No explosions or magic smoke.
All is well: the indicator LEDs all light up nice.
I'm getting +/-37v unloaded on both PSUs. They are 24v transformers so 24*1.41=34v was what I was expecting. I will be curious to see how much they sag under load. Test 2 was the speaker protection boards. The left side is triggering fine on start up. The right side is not. Next time I have some time I will swap the 2 boards over and see if the fault follows the board which should tell me whether the fault is in the wiring or on the protection board.
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Post by colinf on Apr 26, 2021 18:53:31 GMT 12
Unloaded, the secondary would be producing 26vac if you’re getting 37vdc. If power to each protection board is the same at the board terminals you can assume the one not switching on has a problem.
AMR-iFi R&D
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Post by sadface on Apr 26, 2021 22:42:29 GMT 12
Good news,
The fault doesn't move when the boards do. This tells me the issue is with my wiring.
When next I have time, I'll start by pulling apart the wire header and see if I can't find a fault there, otherwise I'll work backwards.
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Post by RdM on Apr 26, 2021 22:53:22 GMT 12
And so it goes ...
The joys of fault-finding! ;=})
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Post by sadface on Apr 30, 2021 15:08:17 GMT 12
I am a little bit flummoxed at this point.
I have re-verified that both protection boards work when plugged into the left hand power supply.
I have also confirmed that the right hand protection board is receiving, AC, DC and GND so there is no issue with receiving power that I can find.
I think my next trick will be to move the power supplies around to rule out some strange issue there.
Assuming that turns nothing up, I think I will have to start poking around the boards themselves to see which bit is not working.
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Post by colinf on Apr 30, 2021 18:21:18 GMT 12
Have you inadvertently grounded something at a screw hole?
AMR-iFi R&D
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Pundit
Post by simonb on May 3, 2021 15:09:06 GMT 12
All drill presses I've seen have mechanical belt/pulley manual speed adjustment. The only 'electronic' one I've actually just has a variable taper pulley. Being AC mtrs, I guess they'd need Variable Freq Drive. sadface - that's a nice buy, that Ryobi - 13mm chuck? Don't want to deflect this thread too much from Colin's cool gain clone (really like the 'short-circuit' main amp boards and separate PSUs. I too have a gainclone as my backup amp) But I am very enthusiastic about my Bosch PBD40 benchtop drill after relatively happily using a Ryobi (as pictured above) for many years. In part I am responding to Owens comment above as the Bosch has proper electronic control (two mechanical ranges) with digital readout of speed. This display can also be toggled to read depth within 0.1mm (and I reckon is good for around that level of accuracy) and of course zeroed at any point. Also has;-Good LED lighting of workplace -Laser cross hairs for the centre of your hole (only sometimes works well, depends on length of drill) -Adequate power. I have stalled it but only doing something silly... (better than the owner being rotated) -Good clamping thing but still bought a standard drill vice as well -main spindle has a lot less slop than the Ryobi (this was a major for me using it every day to make tonearms) Disadvantages-Keyless chuck, a different theme and not convinced. -Drills don't go up inside the chuck much -Unusual moving head thing (rather than table) and round handle for plunging rather than three spoke job. Pro's and cons but the latter win.. -Dog doesn't like the noise -Around $440, so more than Ryobi (very worth it for me but I use it every day)
Simon Brown Design Build Listen Ltd, Makers of The Wand Analogue Products Distributor of Hana Cartridges
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Post by sadface on May 9, 2021 17:01:19 GMT 12
G'day Simon,
I do really like the look of that Bosch, I'll stick with my ryobi for now but if it ever breaks down I will consider your endorsement.
On a side note, many years ago I picked up some bitumen damping panels from you in Brown's Bay. At the time you said you were building a Moskiko. How did that project go?
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Post by sadface on May 9, 2021 17:03:05 GMT 12
Progress is very slow right now as I have a newborn baby girl to keep me busy.
However I finally have some developments today.
I moved the power transformers around and now the fault moves!
Rather inexplicable at this stage as the 2 should be indentical however at least I know where to look now!
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Post by colinf on May 9, 2021 19:58:11 GMT 12
How are you powering the boards?
AMR-iFi R&D
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Post by sadface on May 9, 2021 22:22:46 GMT 12
G'day Colin,
My speaker protection boards are a variant of Rod Elliot's P33 speaker protection circuit.
So to answer the question, it is ultimately powered by the DC output of the power supply. However the loss of AC detector seems to be 'closed'.
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Post by colinf on May 10, 2021 1:06:29 GMT 12
Check you’re getting 0.6v across the b-e junction of Q4, which saturates it and thus turns on the relay. If you’re not getting this, measure around Q2 and R10.
AMR-iFi R&D
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Pundit
Post by simonb on May 10, 2021 14:07:34 GMT 12
G'day Simon, I do really like the look of that Bosch, I'll stick with my ryobi for now but if it ever breaks down I will consider your endorsement. On a side note, many years ago I picked up some bitumen damping panels from you in Brown's Bay. At the time you said you were building a Moskiko. How did that project go? Wow, that is going back a long way! I have designed / built a number of valve-mosfet hybrids over the years (published one in AudioXpress), so similar to Moskkito. Originally "inspired' by the New York Audio labs ones, I gradually moved to Beta follower as the valve bit (SSRR with constant current source in the middle). Don't have time for anything more than the Pass ACA I currently use but would like to revisit the hybrid with 6H30 valves and modern FETs. Will have to wait for a few years at current rate...
Simon Brown Design Build Listen Ltd, Makers of The Wand Analogue Products Distributor of Hana Cartridges
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Post by jerm on May 25, 2021 21:42:52 GMT 12
All drill presses I've seen have mechanical belt/pulley manual speed adjustment. The only 'electronic' one I've actually just has a variable taper pulley. Being AC mtrs, I guess they'd need Variable Freq Drive. sadface - that's a nice buy, that Ryobi - 13mm chuck? Don't want to deflect this thread too much from Colin's cool gain clone (really like the 'short-circuit' main amp boards and separate PSUs. I too have a gainclone as my backup amp) But I am very enthusiastic about my Bosch PBD40 benchtop drill after relatively happily using a Ryobi (as pictured above) for many years. In part I am responding to Owens comment above as the Bosch has proper electronic control (two mechanical ranges) with digital readout of speed. This display can also be toggled to read depth within 0.1mm (and I reckon is good for around that level of accuracy) and of course zeroed at any point. Also has;-Good LED lighting of workplace -Laser cross hairs for the centre of your hole (only sometimes works well, depends on length of drill) -Adequate power. I have stalled it but only doing something silly... (better than the owner being rotated) -Good clamping thing but still bought a standard drill vice as well -main spindle has a lot less slop than the Ryobi (this was a major for me using it every day to make tonearms) Disadvantages-Keyless chuck, a different theme and not convinced. -Drills don't go up inside the chuck much -Unusual moving head thing (rather than table) and round handle for plunging rather than three spoke job. Pro's and cons but the latter win.. -Dog doesn't like the noise -Around $440, so more than Ryobi (very worth it for me but I use it every day) I actually did consider the Bosch drill press when I got my current one, at the time I was living temporarily at Dad's place and we were sharing it. It is an interesting machine with some nice features. In the end I went for something quite a bit more substantial for around $500. I also saw reports online of excessive spindle wobble/runout on the Bosch, I don't know if you've had any issues like that? On a side note, these are the ultimate drill presses, Kiwi company as well! They also do a bench-top model. PS. Sorry for going off topic...
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Post by RdM on May 25, 2021 22:15:16 GMT 12
PS. Sorry for going off topic...
Please don't consider that above (by some sort of ideas or imagined rules?) - "off topic" ! ;- )
Excellent apposite relevant information.
Thanks so much!
Keep on keeping on! ;=})}
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Pundit
Post by simonb on May 26, 2021 7:30:56 GMT 12
Don't want to deflect this thread too much from Colin's cool gain clone (really like the 'short-circuit' main amp boards and separate PSUs. I too have a gainclone as my backup amp) But I am very enthusiastic about my Bosch PBD40 benchtop drill after relatively happily using a Ryobi (as pictured above) for many years. In part I am responding to Owens comment above as the Bosch has proper electronic control (two mechanical ranges) with digital readout of speed. This display can also be toggled to read depth within 0.1mm (and I reckon is good for around that level of accuracy) and of course zeroed at any point. Also has;-Good LED lighting of workplace -Laser cross hairs for the centre of your hole (only sometimes works well, depends on length of drill) -Adequate power. I have stalled it but only doing something silly... (better than the owner being rotated) -Good clamping thing but still bought a standard drill vice as well -main spindle has a lot less slop than the Ryobi (this was a major for me using it every day to make tonearms) Disadvantages-Keyless chuck, a different theme and not convinced. -Drills don't go up inside the chuck much -Unusual moving head thing (rather than table) and round handle for plunging rather than three spoke job. Pro's and cons but the latter win.. -Dog doesn't like the noise -Around $440, so more than Ryobi (very worth it for me but I use it every day) I actually did consider the Bosch drill press when I got my current one, at the time I was living temporarily at Dad's place and we were sharing it. It is an interesting machine with some nice features. In the end I went for something quite a bit more substantial for around $500. I also saw reports online of excessive spindle wobble/runout on the Bosch, I don't know if you've had any issues like that? On a side note, these are the ultimate drill presses, Kiwi company as well! They also do a bench-top model. PS. Sorry for going off topic... Wow, those Nova Drill presses look the next step beyond the Bosch (that highlights the Bosch is not any quieter than a normal drill press). Yes, I saw the runout problem mentioned online. Think it is partially a function of the odd chuck mechanism, possible to get the drill in wrong. Not an excuse if it can happen tho. It is a frustration if not an insurmountable one.
Simon Brown Design Build Listen Ltd, Makers of The Wand Analogue Products Distributor of Hana Cartridges
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Post by jerm on May 26, 2021 9:04:54 GMT 12
I actually did consider the Bosch drill press when I got my current one, at the time I was living temporarily at Dad's place and we were sharing it. It is an interesting machine with some nice features. In the end I went for something quite a bit more substantial for around $500. I also saw reports online of excessive spindle wobble/runout on the Bosch, I don't know if you've had any issues like that? On a side note, these are the ultimate drill presses, Kiwi company as well! They also do a bench-top model. PS. Sorry for going off topic... Wow, those Nova Drill presses look the next step beyond the Bosch (that highlights the Bosch is not any quieter than a normal drill press). Yes, I saw the runout problem mentioned online. Think it is partially a function of the odd chuck mechanism, possible to get the drill in wrong. Not an excuse if it can happen tho. It is a frustration if not an insurmountable one. Yeah apparently that direct drive motor tech was developed for their wood lathe products which are very popular all around the world, then they realised it would be great in a drill press.
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Post by sadface on Nov 30, 2021 21:36:47 GMT 12
G'day Guys, After a long break due to my baby daughter Daphne coming into the world, I have finally had time and energy to tackle this project again. This fix was hilariously simple. The only difference between the 2 sides was the phase with which the AC was taken from the transformer.
Look carefully in this photo and you will notice that on the left side the AC was taken from the yellow wire, on the right side the AC was taken from black wire. This was done in the name of symmetry and for general wiring tidiness.
According to Rod's documentation from his genuine boards, it shouldn't matter where the AC is taken from. On my boards at least, this was not the case.
Changing the wiring so that the AC feed to the loss of AC detector on the right hand protection board was taken from the yellow wire fixed the issue.completely.
The next phase of testing has also been passed. When fed DC into the signal input to the protection boards via a 100k resistor directly from the PSU. The relays trigger and disconnect the amp outputs as they should. The trigger is instant and works on both the +ve and -ve PSU rails.
All in all the protection boards are now functioning perfectly, so now I can move on to testing the amp boards themselves.
Assuming the amp boards work correctly then I might well have this buttoned up for initial noise testing by the end of the week.
I will try it in my system for a bit of 'break in' to make sure I am happy with its performance and that I don't encounter any hum or other such gremlins before proceeding any further on the chassis work.
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Post by colinf on Dec 2, 2021 19:50:00 GMT 12
Nice one, glad you worked out the issue with the protection boards. Age 5 is the year to introduce Daphne to hifi. 😉😊
AMR-iFi R&D
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Post by sadface on Dec 5, 2021 19:20:37 GMT 12
G'day Guys,
Good news and bad news to report.
The good news is that so far everything works perfectly.
DC offset was 1.3mV on the left channel, 1.6mV on the right channel. It tested perfectly on my test speakers with my mp3 player as the source. No issues whatsoever.
The joys of chipamps, if their made properly they work first time.
The bad news is that I appear to have chucked out the 'lid' to the chassis. I did a clear out of salvaged amp chassis recently. I took all the ones I decided had no use to the scrapper. It seems that the one which had the lid which I designed the current chassis around also ended up in that pile...
If I am lucky I will find one in my stash that fits. If I am unlucky it looks like I have to go to the sheet metal guy and get a lid made...
Having one made sounds like a lot of metal work providing ventilation....
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Post by sadface on Dec 6, 2021 20:52:04 GMT 12
Further good news,
I jerry rigged a 'lid' and plugged it into my main system.
No hum whatsoever when plugged into my usual dac, preamp and crossover.
No strange noises to speak of.
A very pleasing result. I'll reserve judgement on the sound as its had no run time yet.
I will report back in a week or so. In the interum I will look into a proper lid solution.
I've toyed with the idea of dispensing with the current chassis concept and buying some cheap generic Hammond steel enclosures and turning this into a pair of monoblocks. This is plausibly a cheaper solution.
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Post by colinf on Dec 6, 2021 22:01:02 GMT 12
Good idea, monoblocks usually have best soundstaging.
AMR-iFi R&D
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Post by sadface on Dec 7, 2021 7:25:08 GMT 12
There is always the question of steel vs aluminium.
The readily available enclosures all seem to be aluminium.
My understanding however is that steel is superior due to being ferrous and therefore able to provide a degree of magnetic shielding.
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Post by michaelw on Dec 8, 2021 14:06:17 GMT 12
Another school of thought considers steel or other magnetic material undesirable.
Eg, DNM with their perspex chassis and casework.
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Post by Graham on Dec 8, 2021 14:35:58 GMT 12
OK, I'll be the 'Devils advocate' What is the big deal with dual mono amplifiers ? Why the emphasis on channel separation to eliminate crosstalk ? My understanding is that in the real world( live performance in normal room ) the typical crosstalk is around 30 - 35 db The left ear is always going to hear some of what is aimed at the right, and vise versa. Not arguing, just asking out of interest.!!
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