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|29th November 2012, 06:22 AM||#11|
Where's Bez ?
Is that a fancy-dress 'Gecko outfit' you're wearing ?
Whilst doing a bit of Teflon research...
...I discovered that it's the only 'known' material that a Gecko can't climb up !
So don't expect to see any hanging up-side-down, off any frying-pans, any time soon.
You could be right qusp.
Perhaps the new millenium may have brought improvements to Tef-tech.
Somehow though, I rec it's just the property of the material.
By the way it wasn't my intention to diss the Ruskie Teflons in the slightest.
The Teflons & PIO's look like the modern world would be pushed to match the quality.
They are obviously well liked as coupling caps by the great DIY audio masses.
With loss less than Polystyrene, who could argue with that ?
All the other plastic-caps I measured, drifted just as much.
Only silver-mica didn't.
My last 2 phono-pre's were stuffed out with Polystyrene's ( no complaints ! )...
...so is this cap-drift actualy audible in yer average RIAA filter ?
Should I worry ?
I dunno...says Bez.
Perhaps I'm being too critical of the poor little plackys.
We did take a gamble on the precise values...
...and as it turned out...
...we just happened to get the 47nF's bang-on & the 15nF a bit over spec. PERFECT !
...just my terrible sense ( or lack of ) humour.
Granny, you can't have me Tefy's just yet OK ?
Next up for testing, some 'Tropical Fish' !
( also unable to scale Teflon )
Those top-boffins at Mullard knew a thing or two about gettin' a groovy sound kids !
Bez & Shaun & Tropical Fish & Mullards Top-Boffins.
|4th December 2012, 03:48 AM||#12|
Just Scored THESE to make a GARGANTUAN mains-filter !!!
As part of the whole 'analogue sources tune-up'...
...Have been looking a bit also at mains-filters.
We have had various stabs at these in the past...
...and used a few 'totaly rubbish' commercial offerings as well...
...EXPENSIVE and not worth toffee, in my opinion.
We thought we'd make one about 100 TIMES BIGGER ( at least ) than what we have seen.
More on mains-filters soon...
...in the mean time...
...get a load of this lot !!!
If anyone's got any favorite circuits & schematics for mains-filters...
Or any build-photos, of GARGANTUAN mains-filters.
Had a quick search...
...but can't find any good links.
Anyone got any ?
|11th December 2012, 10:48 PM||#14|
L.I.S.N. - ( Line Impedance Stabalization Network ) - to THIS
Been looking into various mains-filter ideas, for the new phono-preamp & TT refurb.
Found this interesting device...
...obviously quite a bit going on inside, other than just a mains-filter.
Line Impedance Stabalization Network.
Seems to contain a mains-filter to MIL-STD 461 e & f ( military standard )...
...and perhaps other PSU bits & bobs.
Aparently...a standard, high-performance, test-setup, mains-filter for EMC ( in & out ) testing of military spec. hardware.
Anyhow, thought it looked interesting so here it is !
Values are :-
C1 - 8uF
C2 - 250nF
R1 - 5 Ohms
R2 - 1K Ohms
L1 - 50uH
A Schwarzbeck NSLK 8127.
|16th December 2012, 02:35 AM||#15|
Listen to W I R E ! baby . . .
Holy WIRE-WOUND boy wonder !
Gotham City can't resist this...
...Dr. Ohm & his WW's !
...That took ALL DAY.
Been meaning to do it for a while.
The humble resistor.
Where would we be, without loads & loads of loads.
Decided to go 100% wire-wound on the new projects.
Finally got all the little critters coralled-up, ship-shape & Bristol.
Still a few parts to get...
...quite FUN this bit...
...seem to be heading away from 'modern' bits at the moment...
...back to the 60s' & 70s' era of E.M.I., Mullard & Lemco.
( top-notch stuff ol' chap...WHAT ! )
Power supply boards, seem to be getting speced out pretty darn modern...
...but the phono boards seem like they'll be fairly 'vintagely' populated.
Whatever next ?
|18th December 2012, 05:13 PM||#16|
DIY non-inductive W.W. ultra-low-noise JFET source-resistors ( part 1 ).
Anyone who's been tuned in to Squirrel & G-Man will know...
...we're just simply wired about wire-wounds this Christmas !
Yeah...Hi Santa...I'd like a stocking full of wire-wounds...please.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
...It was brought to the attention of the R&D team @ The Space Egg Corp ( me ),
That JFET source-resistors may well be functioning quite well as 'noise generators' also.
"Do you know any good wire-wounds ?", was the question.
Well, yes, kinda.
"Are they non-inductive ?", er...um...I dunno actualy.
"Can I get them in loads of different accurate values ?", not realy, & no, only 5% tolerance usually.
"Are they really big ? Will they fit on my board ?", er...well...yes they are, & no, they probably won't.
Possibly not an off the shelf, plug and play item...
...call Space Egg's R&D boffins, they might be able to lash something together.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Some time later...
...The R&D team emerged from the lab, with a prototype product.
Having promised development photos, a top level expert in miniature scientific photography, was called in to document the work.
Bud 'Rollei' is a pretty vintage-dude.
100% analogue, with his trusty 2 1/4" Sq. Rollei twin-lens; he was the obvious choice.
Bud's popped flash-bulbs with the best of 'em, back in his 'LA Confidential' type, early B+W paparazi days.
Moving on to snap all the top-drivers in the 70s' Formula 1 scene & hangin' out with George Harrison; and more recently, has specialised in 'chocolate box' photography for Cadbury's.
( the lady love's Milk Tray...yep...that was Bud )
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
We will leave Bud to supply a picture or 2, that say 1000 words...Phew !...
...+ a bit of blurb from the R&D boffins.
Here's Bud at the latest Museum Of Modern Art exhibition...
...photographing an exhibit called - 'Copper Resistor Lead-Outs'...
...by Carl Judd or Donald Andre; or something like that...
...70s' American minimalism; so I'm told, by 'her in doors'.
Further DIY pics to follow............................................ .
|19th December 2012, 12:28 AM||#17|
( part 2 ) We Will Wequire WIRE !
OK...we managed to secure the MOMA exhibit Bud photographed, for our component leads.
Next up WIRE !
Morgan Jones says in his exellent book 'Valve Amplifiers' ( I keep saying that !...it really is great though; cheers Morgan )...
...basicaly says that the noise created by conventional spiral-cut metal-film resistors; is caused by " tatty edges", left by the blade or laser, that cuts the spiral.
He also says that this can vary greatly, depending on depth of cut, sharpness of blade, quality of substrate etc. etc. etc.
This was quite interesting, because he doesn't mention the metal-film itself, as being inherently noisey.
Having recently 'busted open' a large-sample of various resistors, to see what was inside; we discovered the only non-spiral-cut metal-film resistor we had.
These were originaly from a Sony pro-audio tape-machine from the 60s', and are totally exellent resistors, as far as noise is concerned.
In fact, before 'busting open' a sample to have a look, we were totaly convinced ( wrongly ) that they were wire-wounds.
Hand-made wire end-terminations & glazing; but on inspecting, a THICK-FILM construction on ceramic, with NO spiral-cut or 'tatty edges'.
This machine was 'whisper quiet', uncanily so in fact; and it was a shame to scrap it for parts, but there were so many hardened specialised rubber parts in it, the unit was mechanicaly unuseable.
The pre-amp sections though...WOW !
The sound came out of 'nowhere' & this was valve gear BTW as well...n i c e !
...we needed some resistance wire...
...and found a few sources to check out.
See Bud's pics.
|19th December 2012, 11:08 AM||#18|
Just one more thing about the Sony pro-audio tape machine...
...and we'll get on with the DIY source-resistors story...OK ?
It DID have wire-wounds in it AS WELL AS the hand-made thick-films...
...these WERE used in typical valve-load positions ( as I recall )...
...might get Indiana Jones to 'dig it out' the back of the garage, for another shufty !
...a few points about the WIRE we found...
...and on to the R&D Depts. construction photos...
. . . n i c e !
|19th December 2012, 12:23 PM||#19|
( part 3 ) The Wire Is Wedy To Wound.
The first wire we found was from a disassembled 70s' instrumentation pot.
n i c e !
It WAS a 200r pot ( until we bust it ! )...
...it's now partialy 'un-wound', & tested by the Space Egg R&D Dept.
TOTALY USELESS !...for the very low-value first-stage source-resistors...
...far too short a length, for the required resistance ( not easy to accurately trim ).
...PERFECT ! for the 43r resistors needed for the second-stage sources...
That's a BIG muther !
Could make a good source-resistor ( maybe ? )...
...trouble is, it won't fit on the board, next to the K170's ( shame )...
...Bud didn't get a shot of the other 'biggies' we turned-up...
...but they were from a 'skip-dive' a few years back; outside the local cell-phone tower...WOOeee !...free parts !
These are metal resistance-STRIP, wide-wound on a ceramic-core, un-potted.
I think, from some kind of 3-phase filter ( we have 3 of them ! ).
TOTALLY USELESS ! for K170 source-resistors...
...but COULD be good for knocking up some 0.33r's for a typical power-amp ( they're stashed baby ! ).
Hit the mother-lode at last !
A nice roll of 60s' scientific-wire from my Dad ( R.I.P ) 's workshop.
EXTREMELY shinny, NO 'tatty edges', PERFECT length & resistance to create the low-value wire-wounds with.
BOO JAH !
It's quite difficult for Bud to take R&D photos, whilst we are soldering...
...so in true 'Blue Peter' fashion...
" Here's one I made earlier "
A Space Egg engineer QC's the connections on the prototype resistor.
( in the background; a nice 1K WW from the Sony tape-machine )
|19th December 2012, 11:15 PM||#20|
( part 4 ) " Would you like your Tropical Fish grilled Sir ? "
" Yes please...and served with a sprinkling of Teflon "...
...So far, so good.
In the 'Blue Peter' styleee, one we made earlier...
...we could have insulated the lead-outs & resistance-wire...
...with some 'sticky-back-plastic' or some of Val's old tights...
...but we ( fortunatly ) didn't.
Could just go 'nude' on this of course ( as is the current 'audiophile-vouge' )...
...the resistor could just be 'a loop of wire', sticking-up on the board...
...or sleeved, and just heading back to the PSU-, where it's going anyhow.
...The Space Egg R&D Dept. were given the spec. to make a 0.6" pitch, user-friendly component !
So we need 'audiophile-grade' insulation and some encapsulation & professional labeling as well.
( looks better for 'the pack shot' also...
...the marketing-boys are gonna luv it ! )
The lead-outs are insulated with Teflon-tubing...
...and the resistive-element, with Teflon-tape.
BOO JAH !
Those funky Professors @ Mullard, came up with some pretty jazzy packaging for their parts, back in the swingin' sixties...
...so what better inspiration for our enigmatic-ensapsulation, than the ' Tropical Fish ' !
Bud 'Rollei' kindly provided these pics !
1. Styrene-substrate in Rotring isometric ellipse shape.
2. Mullard Tropical Fish, from the swingin' 60s'.
( anyone care to speculate on the component value ? )
3. Substrate close-up.
( transistor to illustrate size only & is NOT included in your purchase )
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