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For want of a better name: the HackerNAP board

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TR1 should be higher than TR2. So for instance 500 / 550.

10% is about right but not sure how much higher is acceptable. Hopefully Martin or Malcolm should clarify this.
 
Good point Mark, yes 10% is about all the difference you'll find when i tested some. We may have to test a lot to get these.
 
The first step was to sort 500 of them very rapidly into buckets (actually a seedling tray) in step of 10. Maximum hFE variation was 90, but the lower buckets were fuller than the upper ones. Just by eye, the distribution is

bucket 0 - 16%
bucket 1 - 25%
bucket 2 - 15%
bucket 3 - 10%
bucket 4 - 10%
bucket 5 - 8 %
bucket 6 - 7%
bucket 7 - 5%
bucket 8 - 2%

Base hFE is about 300 according to this meter - the parts are specced as 330 average, so it's not too far off.

With that kind of skewed normal distribution, the low hFE values are concentrated and the high ones are spread out - so it is quite easy to get matches of "10% or more" but a lot more time-consuming to get exactly 10% - especially given the limitations of this meter and external factors such as ambient temperature.
 
I can't speak for Carl, but I understand he was moving continents and may be offline/distracted for a while. I'll let him know of the continuing interest on PFM via Facebook. At least I know he's there from time to time.
We have contact!

James
 
Good idea - just called Avondale, and just like the last time there was an instant and very helpful response.

In a nutshell, it doesn't matter too much as long as TR1 is higher than TR2... "don't take the instructions too seriously". (I guess the instructions are worded so that even a clot like me cannot really go wrong).

It seems that TR1 & TR2 should have "close" hFE values, so +10% is the target to aim for but a bit of variation either side of that is fine. That's very good news as it makes the matching process a lot less fiddly.
 
Thanks to all for your patience, and thanks again for the many votes of confidence. I've got a confession to make, though. In the process of packing I've discovered 4 packages of boards that are unsent, and one more that got returned due to incorrect address. Although I've misplaced the returned one at the moment. It's all very upside down.

I've got two packages for John S., one package for Jim B., and one package for Danny R. Danny, I still don't have your address. I've asked my wife to bully me into making sure they get posted ASAP ;)

Simeon, all the spares are packed up in bubble wrap, stored in a box that's stacked under boxes, in a pile of boxes. I'll do my best to locate some spares to replace those that went missing in the post, but I can't promise it will be soon I'm afraid. I do intend to replace them - I don't want anyone to go without.

Flashgo: I found the circular cutting jig for the router. It's a really nice perspex one with very fine-grained adjustments - shall I post it to you?

Sorry for ignoring you all! It's reassuring to see that despite my inattentiveness, several builds are taking shape.

Cheers,
Carl
 
Hey Carl, good to hear from you. I'll put my being patient hat on and cram it right down over my ears! Hope the move is going ok.
Simeon
 
Hi Carl

I trust that your relocation plan/s are proceeding well .... as well as these things do go - that is ...... thank you for taking time out to post here.

The remains no rush to receive the boards as they will not be getting built until the bad weather comes in the winter - we're absolutely sweltering here in bonnie Scotland .... and please put them into one package ( John S ) .... and it can wait until after your move to post them off should that be a preferred option for you.

Anyway take care ..... and I must get oot intae the garden and work on my suntan ....
 
Ok... I think I've responded to all the emails in my pfm backlog. If I missed you, please let me know.
 
Hi Guys I also missed the group buy on Hackers NAP PCB'S has anyone got a pair of boards I could buy will pay the going rate and p&p thanks for looking Bob
 
Hi Chaps

Wondering about output tranny mounting. Is it OK to have them wired on flying leads? It will make board mounting a lot easier in the case.

Cheers

Gareth
 
Wondering about output tranny mounting. Is it OK to have them wired on flying leads? It will make board mounting a lot easier in the case.

You can do it but it's an untested configuration. You'll also lose the benefit of the tightly-squeezed-in 470uF decoupling caps.
 
Ok folks, the good news is that I located the boards amongst the debris. The bad news is that I did it too late to post today. Tomorrow morning looks like a champ :)
 
Carl,

Forgive me if this question has already been answered, but is the HackerNAP unconditionally stable if not fed from a bandwidth-limited preamp (e.g. NAC) and not hooked up via NACA5 downstream?

James
 
Carl,

Forgive me if this question has already been answered, but is the HackerNAP unconditionally stable if not fed from a bandwidth-limited preamp (e.g. NAC) and not hooked up via NACA5 downstream?

James

I don't know about the bandwidth limiting part, I've never tried, but I have used the HackerNAPs with very low-inductance Mogami speaker cable without any trouble at all.

I've tried the HackerNAPs on the end of an all-digital rig using PD/Neil's diamond buffer pre (I can't remember if that uses low-pass filtering or not) and your Ergo IXs, and also on an analog rig on the end of Flashgo's LP12/Starfish rig into Briks. In both trials it was as solid as a rock, no trouble at all.

I hope that's of some use! What preamp are you planning to use?

Carl
 
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