The ultimate DIY? A Stax SRM-T2!

[luvdunhill]

Craig:

Why not look locally for your wire? I've used this source in the past with good luck:

WIRES.CO.UK Online Catalogue

Nate:

I haven't had that experience, but thanks for the heads up.

[Craig Sawyers]

Craig:

Why not look locally for your wire? I've used this source in the past with good luck:

WIRES.CO.UK Online Catalogue

They are good - and I've used them before for odd things like bifilar transformer wire. I already looked at their site before going the eBay route, but they don't do colours. I could of course have used ident sleeves to keep track...

The eBay guy says that these are Thermax wires, 19 strand, 22AWG with 1.24mm OD. The Thermax Mil-spec site has this construction and OD listed as "medium wall", and has a voltage rating of 600V, For comparison, the Thermax "heavy wall" has a voltage rating of 1000V.

So it looks as if I will be OK with the stuff I've ordered.

[guzziguy]

Bought plenty of wire from him. Good stuff, conducts electricity like it should

Yes, but does it pass the bass too?

[Dreadhead]

Yes, but does it pass the bass too?

more specifically the bass impact....

[kevin gilmore]

You definitely NEED 20 gauge for the filament wires !

And a 16 gauge wire for the master ground.

[spritzer]

That means moar bass then?

[Craig Sawyers]

You definitely NEED 20 gauge for the filament wires !

And a 16 gauge wire for the master ground.

Check

[Voltron]

Gotta let the big basses through!

[Craig Sawyers]

Kevin pointed me at Future Electronics as a source for the Aavid 4171G ceramic TO220 insulators - at the time they had 9000 of the suckers. Since then they have run out (as have Digikey), with delivery estimated at the end of July.

Does anyone have any alternative sources? I've come up dry, apart from a company that wants 90c each (ten times Future's price - remember that 62 are needed!).

[Craig Sawyers]

I have have boxes full of parts to start board stuffing, using my fusion of Kevins parts list (with exceptionally helpful Mouser parts numbers) and my restructured version. So far so great - with two problems.

The first is the ceramic insulators, mentioned above.

The second is the Wima MKP10 0.1uF 1kV polypropylenes, of which 8 are used on the amplifier and 2 on the power supply. I alas had a brain fade and bought 27.5mm pin spacings, and the board is laid out for 22.5mm spacing. Wima actually made several versions of each cap with different spacing. That is not a disaster - apart from the fact that the 22.5mm version is as rare as chicken teeth - Mouser are on an October delivery.

Problem is that very few that I have found seem to stock this, and the MKP10 seems to be unique in its ability to withstand AC - 600V rms. There are plenty pulse polypropylenes that will physically fit, that handle 250V or 350V ac (Vishay, Epcos/Philips etc), but not the 600V rms of the MKP10.

So I guess there are two questions:

1. Anybody know of stock somewhere? Tried Mouser, Digikey, Future, Farnell, RS Components and Google.

2. How critical is the 600V ac rating? My guess is this is quite important, but KG's comment would be very welcome....

[Beefy]

1. Anybody know of stock somewhere? Tried Mouser, Digikey, Future, Farnell, RS Components and Google.

Is it the 505-M10.1/1000/10? That is the part that the Exstata uses in its bias supply, that they got from a distributor other than Mouser. Let me have a search for you......

[Pars]

Try TAW Electronics... they seem to have them, thought their search function is a bit wonky.

Capacitors, Resistors, Connectors, LED, Varistors from WIMA, AOP, PIHER, NEMCO, FISHER, CAPAX, ARCO, SAURO, SFI

If you go to the MKP10 section, try page 5.

[Beefy]

Here it is: Capacitors, Resistors, Connectors, LED, Varistors from WIMA, AOP, PIHER, NEMCO, FISHER, CAPAX, ARCO, SAURO, SFI

Ah, too slow!

[kevin gilmore]

Those caps need to handle 600 volts DC. So anything that fits that can do that works.

[Craig Sawyers]

Try TAW Electronics... they seem to have them, thought their search function is a bit wonky.

Capacitors, Resistors, Connectors, LED, Varistors from WIMA, AOP, PIHER, NEMCO, FISHER, CAPAX, ARCO, SAURO, SFI

If you go to the MKP10 section, try page 5.

Thanks Beefy and Pars - that supplier is a must-keep supplier - an interesting line card.

I shudda checked the schematic on this one - as KG points out they are just power supply decouplers and don't need a significant AC capability. Which means that I can source EPCOS B32653A104J ex stock from Farnell. Should arrive tomorrow.

Stuffing beckons!

Incidentally, Mouser are pretty impressive in my book. Order was packed and shipped on Monday stateside and arrived on my doorstep in the UK today, Wednesday. Shipping from the US - free on orders over

[Beefy]

Incidentally, Mouser are pretty impressive in my book. Order was packed and shipped on Monday stateside and arrived on my doorstep in the UK today, Wednesday. Shipping from the US - free on orders over

[Pars]

I used to prefer dealing with Digikey until a couple of years ago. Mouser has really stepped up their game.

[kevin gilmore]

I now have 9 sets of heatsinks done,

15 sets of fronts/backs done

8 sets of tops/bottoms done

(in addition to the 3 sets of everything already shipped)

going to do 6 knobs tomorrow

and a bunch of stax jacks (5 and 6 pin)

next week.

2 chassis with knobs should go out for finishing on friday or monday.

Spritzer gets a different color knob.

Only thing left to do is measure for and make the mounting brackets for

the DACT.

Unless i decide to do something stupid like making aluminum feet.

Or titanium feet, or some other very silly thing.

Gold/platinum with or without diamonds available special order

Edited June 16, 2010 by kevin gilmore

[Craig Sawyers]

I now have 9 sets of heatsinks done,

15 sets of fronts/backs done

8 sets of tops/bottoms done

(in addition to the 3 sets of everything already shipped)

going to do 6 knobs tomorrow

and a bunch of stax jacks (5 and 6 pin)

next week.

2 chassis with knobs should go out for finishing on friday or monday.

Spritzer gets a different color knob.

Only thing left to do is measure for and make the mounting brackets for

the DACT.

Unless i decide to do something stupid like making aluminum feet.

Or titanium feet, or some other very silly thing.

Gold/platinum with or without diamonds available special order

Awesome Kevin!

Mention of the platinum reminds me of my Dad, who ended his working life in charge of Quality at Burgess Microswitches. For some years the spring loaded rubber swing doors to the factory were propped open with a hefty spool of metal ribbon - 30-40lbs or so. No-one gave it much thought - must be steel - and so just pushed it into place each morning. My Dad eventually took a chunk and sent it off for assay just to find out what it was. Yup - platinum. Today's price is around

[Nebby]

That's one expensive doorstop!

[kevin gilmore]

just goofing around... 2 inch diameter teflon, black delrin insert, each knurl individualy machined.

(lotsa machine time)

http://gilmore.chem.northwestern.edu/tknobbig.jpg

4 chassis and 6 knobs should ship on monday for polishing/finishing. Then in about 3 weeks

when they return, the first 4 people who speak up can have them.

Birgirs chassis is now in iceland at customs...

Stax jacks still next week, and angle bracket for the DACT (just finished measuring and designing it,

same stuff as the heat sink angle pieces)

The pot which just showed up one month later from birgir is one of the pots

for the kgsshv. (damm that volcano)

Edited June 18, 2010 by kevin gilmore

[Voltron]

just goofing around... 2 inch diameter teflon, black delrin insert, each knurl individualy machined.

(lotsa machine time)

4 chassis and 6 knobs should ship on monday for polishing/finishing. Then in about 3 weeks

when they return, the first 4 people who speak up can have them.

Birgirs chassis is now in iceland at customs...

Stax jacks still next week, and angle bracket for the DACT (just finished measuring and designing it,

same stuff as the heat sink angle pieces)

The pot which just showed up one month later from birgir is one of the pots

for the kgsshv. (damm that volcano)

Can I speak up now or only in three weeks?

[kevin gilmore]

Voltron has spoken. You want one or both chassis this time?

[Voltron]

Voltron has spoken. You want one or both chassis this time?

Actually, I should withdraw that claim for now because others in the group may be closer to building than I am (Nate is) and I don't want to hold them up. I should hold off.

[struts]

when they return, the first 4 people who speak up can have them.

Raises hand, bats eyelids, ...