LA3A 500 BUILD

[janczmok]

Okay, this stuff clears (nearly) everything up, what i meant:

D1 -D4 are named in the main PCB, those are 1N4003,
D1 and D2 are also named on one of the addon PCB, so i am asking which type ? 1N4148 or 1N4003 as well.
And i mentioned that CR1+2 is named in the parts list, but i also cannot find it on board, hence my question
if D1 and D2 on the addon == CR1+2.

But on the schematics this can be seen, so thank you for this additional.

 

[peter purpose]

1N4003 for the six then.

 

[zmgwg]

I have some spare OA91s, pm if somebody want some

also found this https://www.studioelectronics.biz/sunshop/index.php?l=product_detail&p=1217 but it doesn't seem that attractive price wise 

 

[Ianbryn11]

any news on a complete parts kit available? Just ordered the Hairball trafo kit...

 

[JAB]

just putting together a parts order, and am suddenly aware of just how little I know about relays...
this looks good to me, but if anyone can spot a reason not to order it, or knows a better option, it would be much appreciated.

http://ca.mouser.com/Search/ProductDetail.aspx?R=G5V-2-H-DC12virtualkey65300000virtualkey653-G5V-2-H-DC12

 

[peter purpose]

That should do you nicely.

 

[JAB]

excellent... thanks Peter

 

[dmp]

About how the relay is powered... I was just going to stick some 12v relays in that I had pulled from something else, but I don't know their current draw.  I'm wondering if RRL or anything else has to be changed if the relay draws more / less current? It appears like the relay coil is in series with RLL, which sees the positive voltage (16v minus two diode drops... ~14.6v).  I'm not sure how the relay is seeing 12v with RLL only 10 ohm.
I think you would want to calculate RLL so that the Relay sees 12volts. So, for JABs relay, the current draw is I_relay=.0125 amps. You want RLL to drop 2.6 volts, so RLL=2.6/.0125 = 208 ohms.

 

[dmp]

Any guidelines for the heatsink on the output transistors? Do they need to share a heatsink like in your pic for temperature stabilization? Do you have a part number for the one you used so I can compare specs?

 

[peter purpose]

No special requirements for the heatsink except if using just one... insulate the cans... as 2 voltages don't mix.
I used part of an old chipset heatsink and sticky pads.

RRL as required.

 

[janczmok]

Short question regarding the EA-11184-500 Autoformer: Which colors do align with what pos on the PCB ?
I'm not able to find a datasheet or color coding outlining this. 

 

[peter purpose]

From the picture on the hairball site it looks like black-5 red-2.5 blue-.31, but don't take my word for it.
BTW... I had to dress the wires from the standard part quite strangely, but think that these will need to be tightly twisted.

 

[JAB]

Don't know what's up with mouser on these, but the 2n4037 comes up out of stock, with a 1 week lead.
Just in case anyone wants another option, these are also available through newark in the USA

http://www.newark.com/multicomp/2n4037/bipolar-transistor-pnp-40v-to-39/dp/35C0712?Ntt=2N4037

or in Canada

http://canada.newark.com/jsp/displayProduct.jsp?sku=35C0712&CMP=KNC-G-SKU-Multicomp&s_kwcid=TC|21814|2n4037||S|b|5961982252

both show them in stock for roughly the same price as mouser

 

[Sammas]

Hey guys,

I think there is an error in the BOM.

For RV23 & RV31 you actually need 3299P type trimmers. The ones listed in the BOM currently appear to be SMD, not through-hole.

 

[peter purpose]

Oops... sorry boys.... bom updated. :-[

 

[Sammas]

No sweat, Peter 


Any aussie chaps placing an order with mouser in the coming days?

 

[peter purpose]

3296P is the part you actually want.

 

[Sammas]

3296P is the part you actually want.

Thank christ for that... 250k 3299P's are few and far between it seems.  :-\

 

[kato]

I brutalized an innocent T4B for the guts.

Seems like such a waste for 2 opto cells and one light emitter. But it had to be done...

 

[zayance]

Ouch, all my condolences 

So the can is silicon glued or Epoxy? seems like epoxy for the mess...