tubularbells Posted June 6, 2020 Share Posted June 6, 2020 8 minutes ago, HdB said: Doug, you could use those transistor mounting clips (or actually the bar version from Jaycar, etc) with the hole in the middle - you only need 4 holes per heatsink then for the 8 fets - it's a simpler way to mount the single bridge diodes on heatsinks too. There's also some specific spring clips from Mouser, RS, etc that apply a more constant pressure on the transistor case/device - these also come in dual clips (can easily cut them apart) but do need 1 hole per transistor for accurate control of spring clip's tension These save worrying about drilling/tapping accurate vertical holes for the retaining screws, which can be a real PIA! Yeah been thinking about this very thing as those low pressure clamps and silpad certainly make life a little easier. Link to comment Share on other sites More sharing options...
DQ828 Posted June 6, 2020 Share Posted June 6, 2020 Slowly getting there, I'll dunk it in some resin next. 1 Link to comment Share on other sites More sharing options...
DQ828 Posted June 7, 2020 Share Posted June 7, 2020 I managed to get the resin done today, but as always seems to happen with expoxey resin it manage to find a way out, hence the yellow tape to stop the leaking. I had a silicone seal where the clear plastic met the sewer pipe cap but it got through anyway. I coated the inside with mould release but now the resin has got between the clear plastic and the cap it looks like I'll be cutting it out. 1 1 Link to comment Share on other sites More sharing options...
oohms Posted June 7, 2020 Share Posted June 7, 2020 SB acoustics 'bromo' in construction.. hopefully finished tomorrow 5 Link to comment Share on other sites More sharing options...
RankStranger Posted June 8, 2020 Share Posted June 8, 2020 made some aluminium plates for the binding posts I got from @andyr they need a final finish but I’m pretty happy with how they turned out. My 60L seas FA22 full-ranges are more or less in the finishing stages now so I’m going to hold off posting more pics until they’re done then I’ll give them their own thread. Shouldn’t be more than a few weeks but I’ve never veneered on this scale before so I’m going to prioritise care over speed happy to hear any home-veneering tips anyone has wrt glue, clamping, etc. Surfaces are approx 300 x 600mm and 300 x 500mm so not huge but not tiny either Link to comment Share on other sites More sharing options...
andyr Posted June 8, 2020 Share Posted June 8, 2020 42 minutes ago, RankStranger said: made some aluminium plates for the binding posts I got from @andyr Very cool, Simon! Can you tell me what drill size you used for the main barrels? Also, how did you make the notch in the side of the hole? Thanks, Andy Link to comment Share on other sites More sharing options...
RankStranger Posted June 8, 2020 Share Posted June 8, 2020 (edited) 31 minutes ago, andyr said: Very cool, Simon! Can you tell me what drill size you used for the main barrels? Also, how did you make the notch in the side of the hole? Thanks, Andy It’s 11.5mm just made with an 11.5mm drill bit. I started with 11 per the specs but it wasn’t quite big enough. I did the notch with a small jeweller’s file Edited June 8, 2020 by RankStranger Link to comment Share on other sites More sharing options...
andyr Posted June 8, 2020 Share Posted June 8, 2020 1 minute ago, RankStranger said: It’s 11.5mm just made with an 11.5mm drill bit. I started with 11 per the specs but it wasn’t quite big enough. I did the notch with a small jeweller’s file Thanks, Simon. Rather than all that filing ... I'm thinking I'll try drilling a second, small hole on the circumference of the big hole. Andy 1 Link to comment Share on other sites More sharing options...
RankStranger Posted June 8, 2020 Share Posted June 8, 2020 20 minutes ago, andyr said: Thanks, Simon. Rather than all that filing ... I'm thinking I'll try drilling a second, small hole on the circumference of the big hole. Andy Be careful because there’s not much between making a round hole big enough to take the square nub and being visible outside the circumference of the washer Link to comment Share on other sites More sharing options...
HdB Posted June 8, 2020 Share Posted June 8, 2020 That's how they make those 4mm non-metal connectors out of Teflon - they first drill a 1mm hole (on the perimeter of a 4mm circle) then drill the 4mm hole for the insertion of a 4mm plug - gets a direct surface connection between the plug and a 1mm dia wire - can do with 2 or more wires of different diameters. I tried this awhile ago but not sure if it made any difference in practice - more of an academic exercise about different metals, solders, bare wire, corrosion, contact coatings, etc Still quite keen on the 4mm BFA-Z plugs (beryllium copper) and sockets - a bit hard to find the plastic 'jackets' for them these days Link to comment Share on other sites More sharing options...
stereo coffee Posted June 8, 2020 Share Posted June 8, 2020 On 06/06/2020 at 9:47 PM, DQ828 said: Slowly getting there, I'll dunk it in some resin next. Hi Simon Regarding your image with a shield around the toroidal, there is a general rule I always follow, that is never to circumnavigate earthing wiring around any transformer. The shield is quite OK, and a good idea, on its own, which can be viewed as a Faraday shield https://en.wikipedia.org/wiki/Faraday_cage The green earth wire therefore is not needed to touch other earthing, or indeed the shield you have made, should also insulate from earth chassis metal. The reasons for this are that the fields you are trying to cancel from the transformer, are then given possible path to couple, see "What causes Earth Ground loops" https://sound-au.com/earthing.htm I hope that is helpful Link to comment Share on other sites More sharing options...
andyr Posted June 8, 2020 Share Posted June 8, 2020 4 hours ago, RankStranger said: Be careful because there’s not much between making a round hole big enough to take the square nub and being visible outside the circumference of the washer Thanks for the warning, Simon - I shall investigate closely, in due course. Andy 1 Link to comment Share on other sites More sharing options...
DQ828 Posted June 9, 2020 Share Posted June 9, 2020 On 08/06/2020 at 1:20 PM, stereo coffee said: Hi Simon Regarding your image with a shield around the toroidal, there is a general rule I always follow, that is never to circumnavigate earthing wiring around any transformer. The shield is quite OK, and a good idea, on its own, which can be viewed as a Faraday shield https://en.wikipedia.org/wiki/Faraday_cage The green earth wire therefore is not needed to touch other earthing, or indeed the shield you have made, should also insulate from earth chassis metal. The reasons for this are that the fields you are trying to cancel from the transformer, are then given possible path to couple, see "What causes Earth Ground loops" https://sound-au.com/earthing.htm I hope that is helpful The names David Hmmm interesting, the last 2 transformers I had custom built by Harbuch Transformers came with Flux Bands and earthing leads coming off them so I just followed thier lead. The EI transformer I pulled out of of a Mazantz amp had a flux band but I cant say whether it was earthed. My lasted Preamp has one of the Harbuch transformers in to so I might try and sidconnect the flux band earth lead from the Star Ground and seee if anything changes. Well it finished, but it will be sitting on the shelf for a while as I ned to get on and make a stereo cabinet to put all this gear in, and it will take a while! 3 Link to comment Share on other sites More sharing options...
stereo coffee Posted June 9, 2020 Share Posted June 9, 2020 3 hours ago, DQ828 said: The names David Hmmm interesting, the last 2 transformers I had custom built by Harbuch Transformers came with Flux Bands and earthing leads coming off them so I just followed thier lead. The EI transformer I pulled out of of a Mazantz amp had a flux band but I cant say whether it was earthed. My lasted Preamp has one of the Harbuch transformers in to so I might try and sidconnect the flux band earth lead from the Star Ground and seee if anything changes. Well it finished, but it will be sitting on the shelf for a while as I ned to get on and make a stereo cabinet to put all this gear in, and it will take a while! Sorry I had your name wrong David. Yes its the concept of creating a earth in itself around the outer flux of the toroidal, but not inviting what is then nicely contained, to go elsewhere. Some fascinating points about toroidals is flux is highest at the inner core, and when not subject to loading, from circuitry drawing current, flux is awkwardly at its highest. This then goes on with very low current draw circuits to play havoc where smaller than 10va toroidals are used. The circuits I build are 20ma or less, and I always use a 20VA or higher for that reason. Link to comment Share on other sites More sharing options...
aussievintage Posted June 9, 2020 Share Posted June 9, 2020 I don't know how much interest there is in this, but I have turned a raspberry Pi into a poor mans Audio Puffin. I implemented this 2 ways - a command line version using Ecasound, and a graphical version using Puredata which is way cool (picture below). Puredata is a graphical design language for working with multimedia. So easy, just draw lines to connect function blocks. I have all the basic phono stuff working - Rumble Filter, Gain, Phono Equaliser, Scratch Filter, Bass Boost and "Air". Slider controls for the parameters are coloured. I have made extensive use of the same LADSPA audio plugins in both versions. In the picture below it is set up for playing old jazz 78s that I have (turnover 250 Hz, flat (no rolloff), scratch filter 5500 Hz. 3 Link to comment Share on other sites More sharing options...
aussievintage Posted June 10, 2020 Share Posted June 10, 2020 (edited) Lots of improvements. Presets on eq settings, stereo/mono switching and mixing, loudness switch, lots of presets on everything, COMMENTS in the code/drawing Edited June 10, 2020 by aussievintage Link to comment Share on other sites More sharing options...
Red MacKay Posted June 10, 2020 Share Posted June 10, 2020 46 minutes ago, aussievintage said: Lots of improvements. Presets on eq settings, stereo/mono switching and mixing, loudness switch, lots of presets on everything, COMMENTS in the code/drawing This one is way beyond my pay level in this hobby... Link to comment Share on other sites More sharing options...
aussievintage Posted June 10, 2020 Share Posted June 10, 2020 1 hour ago, Red MacKay said: This one is way beyond my pay level in this hobby... Nah, it looks more complicated than it is. You could grab a raspberry Pi, and a hifiberry DAC ADC hat (or other audio interfaces), install Raspbian, Puredata, etc and run my program, and have a poor man's Audio Puffin (that's over $700 on Amazon Australia). Note, I haven't tried a hifiberry hat yet. I have prototyped this on USB interfaces I already had (at 16 bit/48kHz), but I think I'll buy a hat, 'cos it will give me 24bit/192kHz I believe (depending on CPU load etc). The DAC ADC hat has up to 32 dB gain, so, pending loading requirements etc, it may work as is. Link to comment Share on other sites More sharing options...
DQ828 Posted June 10, 2020 Share Posted June 10, 2020 9 hours ago, aussievintage said: I don't know how much interest there is in this, but I have turned a raspberry Pi into a poor mans Audio Puffin. I implemented this 2 ways - a command line version using Ecasound, and a graphical version using Puredata which is way cool (picture below). Puredata is a graphical design language for working with multimedia. So easy, just draw lines to connect function blocks. I have all the basic phono stuff working - Rumble Filter, Gain, Phono Equaliser, Scratch Filter, Bass Boost and "Air". Slider controls for the parameters are coloured. I have made extensive use of the same LADSPA audio plugins in both versions. In the picture below it is set up for playing old jazz 78s that I have (turnover 250 Hz, flat (no rolloff), scratch filter 5500 Hz. Looks like fun Well done Link to comment Share on other sites More sharing options...
aussievintage Posted June 10, 2020 Share Posted June 10, 2020 4 minutes ago, DQ828 said: Looks like fun Well done Haven't had so much fun "programming since I left work Link to comment Share on other sites More sharing options...
oohms Posted June 10, 2020 Share Posted June 10, 2020 What sort of DSP horsepower does a raspberry pi have? Link to comment Share on other sites More sharing options...
aussievintage Posted June 10, 2020 Share Posted June 10, 2020 3 minutes ago, oohms said: What sort of DSP horsepower does a raspberry pi have? Ah, that was the thought that started my experiment. On a raspberry Pi 3B it all runs with about 20% cpu - see the monitoring program below and command line tools. I thought I might need a Pi 4 for more memory and grunt, but not at 48kHz anyway, it is running smoothly. total used free shared buff/cache available Mem: 948280 196428 326716 18012 425136 675984 Swap: 102396 1280 101116 PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 8535 pi -7 0 25764 10260 7624 S 18.2 1.1 61:05.63 pd Link to comment Share on other sites More sharing options...
aussievintage Posted June 10, 2020 Share Posted June 10, 2020 2 minutes ago, aussievintage said: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 8535 pi -7 0 25764 10260 7624 S 18.2 1.1 61:05.63 pd Actually that's just Puredata. Total load seems to stay under 50% easily - that's with Raspbian desktop and VNC running. Puredata and Wish (Tcl) seem to be under 30% of the total. Link to comment Share on other sites More sharing options...
aussievintage Posted June 10, 2020 Share Posted June 10, 2020 Thought it worth a photo of the test rig. As I said, it's only 48kHz capable, but the sound is still quite good. All this stuff is USB powered from the tiny rPi as well. Link to comment Share on other sites More sharing options...
mwhouston Posted June 11, 2020 Share Posted June 11, 2020 I have more pairs of Gold Lion E88CC for yet another SRPP preamp. Bruce of American oddwatt fame has given me a new SRPP design for these tubes. Got all the parts from de lab only had to buy the chassis. Biggest decision is What colour? 1 Link to comment Share on other sites More sharing options...
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