Part Sourcing Assistance/Advice Thread

[luvdunhill]

Got some of the above to play around with, assuming no other suggestions from the peanut gallery

[wokstarr26]

I may have a friend going to Tokyo next year. Any one know of a diy shop she can purchase 2SA1968LS transistor. Tried Google no good

She is verse in Japanese .  I need to finish some old classic kgsshv amps project from the old boards [blue ones] from headinthecloud

mini group buys years ago. I prefer bjt  ccs, I think it sound better even to my old ears.

[luvdunhill]

Good luck! I would probably watch Yahoo Auctions rather than sending a friend to hunt around Akihabara Town. I will be there weekend after next, though and if I see any I will grab them for KG amp fans - don't hold your breath though.

[wokstarr26]

30 minutes ago, luvdunhill said:

Good luck! I would probably watch Yahoo Auctions rather than sending a friend to hunt around Akihabara Town. I will be there weekend after next, though and if I see any I will grab them for KG amp fans - don't hold your breath though.

Thanks I am not holding my breath ;). She goes there regularly and like snopping around Akihabara Town for her gaming hobbies.

Can I use 2SA1831 instead of 2SA1968 if I insulated the device and reduce my supply to +/- 400 Vdc. I am just driving SR507 ears-speaker nutting fancy.

Edited June 2, 2016 by wokstarr26
add notes

[spritzer]

The A1831 does work just fine within the voltage limitations and the A1967 too if you can find any. 

[PretentiousFood]

I think they're web-only, buy Satodenki had some last time I checked. 

[wokstarr26]

On 6/2/2016 at 9:48 PM, PretentiousFood said:

I think they're web-only, buy Satodenki had some last time I checked. 

Thanks for the infor

Anyone build theses transcendentsound.com

I am a novice to tube stuff. Need a low powered class A amp for a EV SP15A / AMT tweeter diy speaker project circ 1980's in the pipe line.

I have an isobaric sub using 2 x SP15A build years ago and still working fine. Like a small fridge but boy they are efficient. Just need a flea powered amp. 

Edited June 4, 2016 by wokstarr26
correct spelling

[mwl168]

Never built the Transcendentsound amp but they have been around for a long time. AFAIK, they are OTL amps. I did build a pair of OTL mono blocks. One thing the true OTL power amps I know of have in common is that they don't like low impedance loads. So I am guessing your speakers' impedance will be a big factor how well the amp will work.

[Tinkerer]

So, somebody tossed out an old Sony Trinitron WEGA KD-34XBR960 on my street, just about the last of the fancy CRT televisions from 2004. Took it in and gave it a once over. The tube was shot but the power supply and most everything else was A-Okay. So my question is, what is worth salvaging out of it? There's a bunch of onboard sinks that are the right pattern and pitch for what is used in many of the project boards here. Also a bunch of high voltage xicon resistors and some power resistors that look spiffy. Probably going to keep the flyback transformer in case I want to do a little plasma speaker build down the road for fun. Bunch of silvered mica and ceramic caps that look good in values I can use. But what about the devices? Anything special in the sand anyone might care for?

 

Edit: Wrote down all the ones on the boards I kept, but its a few dozen different types.

Rectifier bridge on the power supply seems to be a quartet of Vishay IRFIB7N50A's. Those worth keeping at all? They still seem to be in production so doesn't seem like anything special.

At least its nice to get almost a dozen anodized TO-220 heatsinks for free.

Edited June 5, 2016 by Tinkerer

[luvdunhill]

Anyone need anything from this vendor? Need to hit a $250 minimum:

https://www.rocelec.com/

[Kerry]

Here's a fun weekend project.  It's the Super Symmetry Dynalo.

I need some sourcing help on three items.

• Case - It needs to be 5" x 7" x 1.75" (or 1U)  Board is currently 4.8" x 6.8"
• Trim Pots - I wanted 10K surface mount multi-turn.  The pattern I'm using currently is 3A (as listed in DipTrace)
• Push Switches - I need one for the Power (250VAC) SPST and one for the relay (24VDC)  DPDT / SPDT.  If I could find the same switch for both that would be great.  I'd like a metal extrusion through the front chassis.  I've used SPUJ190900 from Alps before, but this would only cover the relay.

Thanks

Some pics

 

 

Edited July 3, 2016 by Kerry

[Mister X]

The first hit for a case with those dimensions was this---->

http://www.mcmelectronics.com/product/CAMDEN-BOSS-CDM8605SL-/21-20350

http://camdenboss.com/enclosures/diecast-metal-boxes/aluminium-audio-cases

 

But the vents are the wrong way and $$

[Kerry]

Thanks.  Yeah, the vents don't work so good.  I was thinking of something like FPE with the 1U side panels, but may from eBay.

[spritzer]

I'm sure you can also find something on Aliexpress for a fraction of that price. 

[luvdunhill]

I would try to make the Box Series 5 fit. More here: http://www.boxenclosures.com

http://www.boxenclosures.com/category/product_details.html?product__id=241584

Trimmer depend on 13 or 25 turn, gull-wing or j-hook. Depends on hand soldering or not. Copal makes some nice small ones.

[Mister X]

Was thinking about the Box enclosure, would also fit in a Hammond, Lansing, Bud and a few others.

5 hours ago, spritzer said:

I'm sure you can also find something on Aliexpress for a fraction of that price. 

No question but getting them delivered can be a whole other story.

 

Turning the whole thing around the other way is not without benefits but not shoehorned into an expensive case trumps.

I like the FPE idea.

Just buy the extrusions, some pre-anodized aluminum sheets cut to fit any size you like.....

Edited July 4, 2016 by Mister X
speelinggg

[Kerry]

3 hours ago, luvdunhill said:

 

I would try to make the Box Series 5 fit. More here: http://www.boxenclosures.com

http://www.boxenclosures.com/category/product_details.html?product__id=241584

 

Trimmer depend on 13 or 25 turn, gull-wing or j-hook. Depends on hand soldering or not. Copal makes some nice small ones.

Interesting site for the enclosures.  Not sure that I will fit into their standard series 5 boxes.

For the trimmer I would prefer 25 turns.  I can fit either gull-wing or j-hook.  I'm going to use a hot air gun for all SMD soldering.  I've got the TPS7A470 / TPS7A33 as second stage regulators.  Definitely need to use a hot air gun for those.

[JoaMat]

TPS7A47/33 - 20 pins and thermal pad within 5mm x 5mm and need of heat sink. Seems to be a tricky one for most of us.

Lovely work!

[Kerry]

Yeah, I may add a spot to support the prebuilt regs with the same chips.

[spritzer]

I think Kerry needs a proper reflow oven...   

[Kerry]

I'd love one. Can I store it with you. I have no room left in my city apartment.

I  could possibly convert my  powder coating oven to a reflow oven

[spritzer]

I'd be happy to store it.    Plenty of space here!! 

[wink]

Birgir would love that as an alternative to sitting in the caldera of a volcano.. 

The lack of sulphur fumes would be an added health bonus.....  

[luvdunhill]

I prefer a mixture of Isopropyl Alcohol and Acetone (60/40), IMHO I think this mixture clean more easily that if you use Isopropyl only

So, this * 1000, thank you for the suggestion!

I am doing a group buy at DIYAudio for high performance (Kerafol) custom die cut TO-3 insulators. If anyone is interested, please PM me!

[Tinkerer]

Bit of a silly question, but what is the best kind of lock washer to use with small nylon screws so they don't strip or snap? Split ring or inner toothed? And best to use a nylon nut or a stainless steel one?

And secondly, in a really high voltage application where you have thick brackets (1/4"), is it better to use a nice ceramic isolator then extend the transistor legs with heavy gauge wire to reach the board properly or to use a thin silicone isolator so the leads don't need extending? I know neither is ideal, but looking for the lesser evil. I was leaning toward silicone but the center hole is 5mm on the ones I have and I was afraid the 1kv'ish voltage would be able to jump the less than 1mm gap between the metal even though the multimeter reads that it's isolated.