Upfront Posted June 18, 2017 Share Posted June 18, 2017 Klipsch K402 horn replicas in progress.. using known size measurements and lots of fiddling around with tractrix spreadsheets and CAD.. might put up a build log later Definitely need a thread for this mate. Looking good. 1 Link to comment Share on other sites More sharing options...
betocool Posted July 10, 2017 Share Posted July 10, 2017 IKEA style build y'all... just missing the instructions... Quick and dirty to spend the arvo with the kids. Class D module, trannie, caps, sockets, connectors, pot*, wire, switch and a metal Jaycar enclosure: It's a bit tight in there, sure, but managed to fit almost all in (save one cap). Works a treat, and the kids can handle "On/Off" and volume. Used with an old laptop and an old pair of Yamaha speakers, now I'll have trouble getting them out of their play room. I mean, really, who had such high end when they were 5 or 7? Oh yeah, it does sound pretty damn good! Cheers, Alberto *as in potentiometer! 5 Link to comment Share on other sites More sharing options...
btd Posted July 10, 2017 Share Posted July 10, 2017 Working on a couple of Pass pre amps B1, B1.2 and B3 to go with my Aleph amps (mini and J) 5 Link to comment Share on other sites More sharing options...
mwhouston Posted July 20, 2017 Share Posted July 20, 2017 (edited) Recently I added even more capacitors to my latest 6L6 SE UL wine box power amp build. More caps in this case is bypass or snubbing caps. All big electros should be snubbed because they are noisy. It works everytime and made the amp even quieter and better sounding. Instantly audible. Cleaner clearer sound all round. The tweeters are 105db effcient and only by putting my ear right up to them is there the faintest light hiss. No hum, buzz or anything. Today I replaced my Xover caps to the tweeter with PIO 4uf caps. The original caps were quality Metalised polies. The Xover is a two way first order. I required 4.2uf so I snubbed the caps with a poly 0.22uf. Once more an instantly audible change. Mids\trebles are crystal clear and dynamics, already high by the fact that it is a first order Xover regardless, also increased. To thinks the Russian PIO military caps were probably $2. Some images to follow. Edited July 20, 2017 by mwhouston 1 Link to comment Share on other sites More sharing options...
mwhouston Posted July 20, 2017 Share Posted July 20, 2017 (edited) The additional caps added to the amp sit across the smoothing\storage caps to the limited HT on the driver tube. To improve sound even more I split the limiting resistors into two feeds. This means each channel has a separate HT feed with its own storage caps improving dynamics and imaging. The caps are oversize at 47uf\450V. These were then also snubbed. There is one other improvement I can make or at least try with the 1st order Xover is to wind a single layer choke (1.063mH). I wind these on a short length of ferrite with heavy enamelled copper wire. I require two neat winds but this produces inter-winding and inter-layer capacitance. My two layers are separated by a layer of electrical tape. But I think I can use even heavier wire on a much longer piece of round ferrite to reduce the winding depth to one. So some inter-winding capacitance but no inter-layer capacitance. After the dramatic improvement from the PIO cap I may give this a go. Here are the PIO caps for the Xover. Edited July 20, 2017 by mwhouston Link to comment Share on other sites More sharing options...
btd Posted July 23, 2017 Share Posted July 23, 2017 Hi all, Finally started on an audio racking system I have wanted to build for some time. Ultimately one room will have a floor to ceiling rack about 2 meters wide. Another room will have a setup approx. 1.2 m high, 1.5 m wide. Both racks will a separate turntable platforms mounted to the wall, isolating them from the racking itself. In the meantime I have started on two mobile sections that I can move around from room to room and slot into the other racks. Loaded up with 55 kgs of sandblasting material for load and deflection tests. Ended up with 1 deg deflection with the load moved out to the front edge. Nothing broke and everything returned to its original position. Lots more to do but at least its at start. Tony 2 Link to comment Share on other sites More sharing options...
Sub Sonic Posted July 23, 2017 Share Posted July 23, 2017 3 hours ago, btd said: Hi all, Finally started on an audio racking system I have wanted to build for some time. Ultimately one room will have a floor to ceiling rack about 2 meters wide. Another room will have a setup approx. 1.2 m high, 1.5 m wide. Both racks will a separate turntable platforms mounted to the wall, isolating them from the racking itself. In the meantime I have started on two mobile sections that I can move around from room to room and slot into the other racks. Loaded up with 55 kgs of sandblasting material for load and deflection tests. Ended up with 1 deg deflection with the load moved out to the front edge. Nothing broke and everything returned to its original position. Lots more to do but at least its at start. Tony I hope that wording in the background is not the name for your new rack! :-) Link to comment Share on other sites More sharing options...
Batty Posted July 24, 2017 Share Posted July 24, 2017 (edited) Decided to rehouse my SUT and Head amp into 1 box, but ordered the wrong size chassis. What do you all think, close enough to be just a little different? Top one is the Akitika MM phono pre, SUT and head amp going in the bottom one. Edited July 24, 2017 by Batty Link to comment Share on other sites More sharing options...
mwhouston Posted July 24, 2017 Share Posted July 24, 2017 @Batty where did you get the eclosure. Link to comment Share on other sites More sharing options...
Batty Posted July 24, 2017 Share Posted July 24, 2017 (edited) China via ebay, wasn't cheap. Just over $70 inc postage. Very solid though. model s2207. Should be fun drilling this, all panels are 2.5mm ali with the front panel about 8mm, weighs around a kilo. The only drawback is it has a cutout for a fused IEC socket (supplied) and there is no mains power going in there. Edited July 24, 2017 by Batty 1 Link to comment Share on other sites More sharing options...
mwhouston Posted July 24, 2017 Share Posted July 24, 2017 @Batty got an eBay link Link to comment Share on other sites More sharing options...
Batty Posted July 24, 2017 Share Posted July 24, 2017 https://www.ebay.com.au/sch/i.html?_odkw=s2207&_osacat=293&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.X2207+chassis.TRS0&_nkw=2207+chassis&_sacat=293 Take your pick Link to comment Share on other sites More sharing options...
Batty Posted July 24, 2017 Share Posted July 24, 2017 (edited) All screws, feet and power socket included. Here it is in bits. Oops, forgot the feet, just 4 rubber feet with a hole in the centre. Edited July 24, 2017 by Batty Link to comment Share on other sites More sharing options...
mwhouston Posted July 24, 2017 Share Posted July 24, 2017 @Batty buggered by the postage. Link to comment Share on other sites More sharing options...
Batty Posted July 24, 2017 Share Posted July 24, 2017 Yes, but did only take 10 days from china. Link to comment Share on other sites More sharing options...
Alistair W Posted July 24, 2017 Share Posted July 24, 2017 (edited) Similar (possibly same) enclosure from another seller on Aliexpress: https://www.aliexpress.com/store/product/Breeze-audio-aluminum-chassis-2207-short-preamp-headphone-amplifier-case/331129_1994694515.html?spm=2114.12010615.0.0.VOvNTF Note: I haven't bought from this seller, just posting this for info as the price is similar to ebay. -Al. Edited July 24, 2017 by Alistair W USD to AUD confusion on my part! Link to comment Share on other sites More sharing options...
mwhouston Posted July 24, 2017 Share Posted July 24, 2017 @Alistair W that's a lot cheaper. Link to comment Share on other sites More sharing options...
Alistair W Posted July 24, 2017 Share Posted July 24, 2017 Looks like about $44 AUD delivered, but 20-40 days lead time - surface post? Good value if you can wait that long Link to comment Share on other sites More sharing options...
mwhouston Posted July 30, 2017 Share Posted July 30, 2017 Ok you have seen it before and above the bonnet it is exactly the same. In the engine room most components are different. This was the prototype for "Silver Supreme" SE UL amp with the JJ 6L6GC tubes and Mundorf Silver Supreme inter-stage caps. That amp I absolutely love and has not moved out of my main system for some months. This amp (the original prototype) was a real rough build, had a hum and sounded too similar to the Supreme. So I tore it down and rebuilt almost from scratch. Only the initial stage of the PS remains even the ceramic tube sockets got swapped out. I want this amp with the 1944 JAN 6L6 metal tubes to have its own character. For that all resistors are 1W carbon film (and not metal film), inter-stage caps are the original Solens. No silver solder here just Jaycar off the shelf but I did use twisted pairs of Cat5 solid core as hookup. The PS has 475uf of electros and the final filter cap to the driver tube (a well used (tests 98) 12AT7 and not a high end Psvane "T" series) is a Russian 4uf PIO snubbed with a 220nf poly. All other eletros in the PS are snubbed with 0.1uf polies. I didn't split the HT feed to the 12AT7 this time as in the Supreme, again to endow a different image presentation. All filaments (AC) are cap snubbed. After chasing down a horrid buzz it is all is now quiet but not absolutely dead silent as the Supreme but it passes the 1M test. Sound is warmer which is strange as the driver tube has no bypass cap which not only reduces gain slightly but drops a lot of the second harmonic. I did this once more to give this amp its own personality. On a short listen (wifes home) it sounded more mellow than the super fast Supreme and as above, warmer. Very different 6L6 tubes and not the ruggedized GCs in the Supreme. 3 Link to comment Share on other sites More sharing options...
Andrews_melb Posted July 30, 2017 Share Posted July 30, 2017 @mwhouston nice amp, how do you find the 10w xse trannies from edcor vs the gxse, sound wise? I know theyd be too big to fit inside a box. Thinking about using a pair of the smaller ones for something soon Link to comment Share on other sites More sharing options...
mwhouston Posted July 30, 2017 Share Posted July 30, 2017 3 hours ago, Andrews_melb said: @mwhouston nice amp, how do you find the 10w xse trannies from edcor vs the gxse, sound wise? I know theyd be too big to fit inside a box. Thinking about using a pair of the smaller ones for something soon Just talking about this amp it was designed to work with the lower power 6L6 (not 6L6 GC) and the base 10W Edcor UL trannies more than handle idle current and wattage. No need to spend any more here. Most OPTs have a lower frequencies rating quoted at full power. Because these OPTs are way under-utilised (2W for a 10W OPT) the lower frequency role off is a lot lower. I would never use open frame OPTs on the top plate of an amp I think they are ugly. But hidden below; cheap and high performing. The electronic engineer who also has a passion for tube amps and has designed all the ones I have built for years also sent me the schematic for the GC version. There I would have to use the higher power Edcor OPTs (15W ) because the idle current is higher. I have box of Edcor 10W OPTs so all my amps for a while will be flea power wonders. He has also designed for me a cathode follower 6C33C, no OPTs! Look out for that one. 1 Link to comment Share on other sites More sharing options...
Batty Posted August 1, 2017 Share Posted August 1, 2017 Holes drilled in rear panel, need to open up the 8 for the phono sockets. 1 Link to comment Share on other sites More sharing options...
btd Posted August 1, 2017 Share Posted August 1, 2017 On 7/23/2017 at 2:39 PM, Sub Sonic said: I hope that wording in the background is not the name for your new rack! :-) No not the name of the rack but it has been producing some at the other end of the room. Some makeshift shelving and its up and running. 2 Link to comment Share on other sites More sharing options...
Batty Posted August 4, 2017 Share Posted August 4, 2017 Latest .... Holes enlarged with a stepped bit, and RCAs fitted The Transformers were already wired up so didn't disconnect them. 1 1 Link to comment Share on other sites More sharing options...
mwhouston Posted August 6, 2017 Share Posted August 6, 2017 I received another request for a Mimic MM phono preamp based on the OPA2134 opamp chip. In the past these have been built on (no longer available) prototype brds. From now on they will be built on vero (strip brd.) brd. Here is my first. These days I leave the battery wires lose for easier battery change. A lot of work in these and fiddly small. This one is a "Black Shadow" which is a standard Mimic in the more compact sexier black Al enclosure. 2 Link to comment Share on other sites More sharing options...
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