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TPR for HackerNap

Good Morning Tim

Thank you for the detailed posting - I believe that I can follow this so very well done - would you be kind enough to provide the supplier & part number of the components. I had a look at Cricklewood this morning and note that there is no real choice - the components looked to be around 50 & 40 V respectively ...... priced at £1.50 & £0.40 each they look like a very cost effective change out. BUT as a long time member of the "numpty" club I would like to be sure

Thank You once again
 
I got my 2sk117's off ebay - can't remember who and the bc550s I had kicking around. I'm sure Cricklewood would be ok
Tim
 
Brilliant Tim. That is a better way to do it than soldering the two devices together and then mounting them directly onto the Hackernap at Q1 , which is what I did. I was concerned that the small extra capacitance of the veroboard might have an effect but your findings mirror mine exactly with regard to the improvement this brings so I doubt any side effects are significant. If mine get nudged accidently there's a risk of a device short, so veroboard mounting is recommended IMHO.

BTW the output impedance can be lowered further by increasing the current through the jFet to a couple of milliamps by adding an appropriate resistor to 0v from the junction of the jFet's source and the npn's base. 24k should give roughly 2ma.

Here's what I did:

[URL=http://s869.photobucket.com/user/John_Luckins/media/img079_zps2f604270.jpg.html][/URL]

John
 
Fetlington board mark 2

0A74bni.jpg
 
I guess track cutting is limited to the stripboard, correct?

Now I am confused about orientation of the transistors /fet. The notes from timH show the flat side of the 2 facing down towards the mounting pins whereas the in situ photo and the photo of the populated board has the flat side uppermost - which is right? Also timH's picture 2 has the rounded side at the top and on picture 3 it is on the bottom

:confused:
 
That's a good spot. The photos of the loose boards are of a separate board ready to go into another hackernap. I'd better check it out
 
2sk117 needs to have flat uppermost. I'll do another drawing but someone needs to check it if they would please
Tim
 
Thanks Tim, 2SK1117 = flat up and BC550c = flat down having just firkled the datasheets. Have just ordered the bits so will do a HN v modded HN v Hypex comparison soon
 
IT'S NOT SUBTLE
Just fitted the proper Fetlington mod board with the added resister to 0v. Clearer, more direct, more small details which all draws you more into the music. I never fired up the interim Fetlington board so this comparison is between the standard HN and the Rev2 Fetlington.
 
I havent got to building mine yet, still more bits to get...
I already have a load of IRF610`s but this will be factored into my next order!

Very Interested to read about the next comparison with the Hypex modules!

And count me in if you go ahead with a finalised SuperReg board, 6 please!!

Cheers
Justin
 
Next step for me is the tpr. I might as well since I have all the parts. After that it's build up the other two HackerNAPs and go active. By then maybe the super-reg will be a live project. Four monos with those r-cores and cap boards is quite a bit of work. Good luck with the six pack ;)
 
I tried from the top the first time. Tricky because once you start soldering the new board in place some of the bits left behind started dropping down through the board. Since then I've been taking the whole amp board out and de soldering the IRF as cleanly as possible. Good thing is that the little 0v pin on the Fetlington is only a few mm from the FE Ov point. It's almost as if I planned it that way ;)
 
Big job to take boards out so will try from top - I did the update to the HN regarding changes in FE capacitors this way and all was well. Tim, please confirm orientation of FET and tranny - flat up on FET and down on tranny ????
 
Cool beans Tim, big swapsies this weekend, will report back soon - it looks like a superb bang for buck mod and it is certainly the smallest circuit board I have ever made / populated
 
All working, no probs. SQ is definitely improved, more detail, more tonal colour. Tight but definitely do-able from the top - every time I open the box I go WOW!, it really is a busy and impressive piece of kit


HN + fetington by mrphil42, on Flickr

Here is the fetington in situ


HN + fetington closeup by mrphil42, on Flickr

I have posted more comments on SQ on my HN Hypex thread but the fetington is excellent value for money, do it. Thanks John and Tim, Phil
 
GWM said:
So I have been running Johns fetlington in place of the original part for a couple of days, it is a definite improvement mainly mid and treble are sort of cleaner especially female vocals are rounder if that makes sence.
I have though for a while that my hackernaps are a bit unforgiving in the mids they tend to be more revealing of harsher recordings at least when I compare it to my NCC200's but this mod rebalances them to an extent no going back for me, nice one John.
makes me wonder how an AWSR would fare directly on the board.
Geoff
Click to expand...

I got a similar sounding improvement by sorting out a star earthing mod on my pre-amp. I wonder if the extra wire to 0V is a contributing factor here.
 
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