Paradise Builders

[Joachim Gerhard]

It eats batteries for breakfast. I put wires to the outside and supply it with my lab PSU.

 

[miepa]

guys,
i wasnt part of the GB, so, low current leds are recommanded, right?
thank you.

 

[Joachim Gerhard]

yes, 2mA types.

 

[difool]

Dubai, can you read german? Nothing against ATLAS,
I ordered according to HB:
Paradise – Transistor matching | Holger Barske

I am new to transistor matching so the question might be silly, but would a device such as the following be useful?

Found at Reichelt: ATLAS DCA55

Your feedback will be appreciated - thx.

dubai2000

 

[FdW]

I will, tonight, have a look at them. At first glance it seems the V(be Q102) is a bit low, and that this is debit of the current unbalance.

Yesterday I did not manage to do this, I will try to do it this evening

 

[dubai2000]

Thanks for all the feedback - including for the link to Holger's page.

dubai2000

 

[Joachim Gerhard]

The Hfe tester that Holger found works well but it does nave have the much higher functionality of the Atlas. If you do only want to select BJTs for the Paradise it is sufficient.

 

[beetle]

Yesterday I did not manage to do this, I will try to do it this evening

No problems. Take your time.

 

[sq225917]

Joachim, I'm worried about transistor matching how close do they actually have to be?

Is it more important to have a good balance between 327 and 337 or more important to have them matched within each quad, ie 4 327 with the same value as each other?

I can get good quads, ie 4 x 327 with identical values, or I can get a good balance with a looser match yielding a combined HFe that matches between 327 and 337. But I can't get closely matched for both...


Failing that does anyone have 8 337 with an HFe of 400?

I will put my list up later today

 

[Benedetto]

After matching approx. 800 each still trying.
I will order again 300 each from a reliable source...

 

[brianco]

Has anyone checked the 'ammo tape' devices from the first group buy? If so what were your general findings regarding suitability in this application?

Many thanks

B

 

[sq225917]

Joe and I have just gone through 1000 transistors from the group buy + 300 I sourced externally. We managed close matching on the 327 but the 337 were 20 higher and looser matched. I guess they will do.

 

[sq225917]

Hopefully this will spur on some responses.

An externally hosted image should be here but it was not working when we last tested it.

All soldered up just wondering about how to wire up the loading resistor? Am i right in thinking it just goes from signal to ground. If so can I place it at the input on the pcb

 

[Joachim Gerhard]

That looks very good. So you have a Paradise R2.

 

[Joachim Gerhard]

I think you must jumper the "Neumann".

 

[Bksabath]

That is R3 with imput offset on top pf board ?

On R2 I have cartridge loading resistor on spare imput terminals as there are 2 sets side by side just on right side of off set pot

 

[FdW]

It looks beautiful, and the lights indicate Xmas is near

 

[miepa]

3W Power resistors

guys,
the 3W Power resistors better be
- MOX
- Metal Film
- Wirewound

whats the best choice for these?

Thanks!

 

[Pepperman]

Hopefully this will spur on some responses.

Sorry, but I think you have mounted the two caps on the upper right (6800µF/6.3V) in the wrong direction.

 

[sq225917]

I had noticed that, amazing that at the time I hadn't seen it. Can't see the wood for the trees.

I do however have other issues, like none of the LEDS lighting up on one board- they are all good though. And 4 of the LEDS on the other board having shorts. Of course they are 4 of the LEDS under the heatsink.

Much work to do, sorting out faults and building a PSU I can actually trust rather than the one I borrowed that i'm not 100% sure of.