New! WNA MKll Head-amp kit.
May 5, 2005 at 9:33 PM Post #361 of 764
Quote:

Originally Posted by BrokenEnglish
yeah... go on, mike.. 220µf certainly should be no problem..
i'll send you some more stuff for your trials next week...
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220pF (picofarad) not 220uF (Microfarad) Udo
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May 5, 2005 at 9:41 PM Post #363 of 764
I'm "really" looking forward to this build...... virgin pads and so much to play about with
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Mike.


EDIT: Udo, get yourself a MKll board man, we can exchange notes.
 
May 6, 2005 at 11:18 AM Post #365 of 764
Quote:

Originally Posted by BrokenEnglish
stop tempting me, british devil...
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...i could get weak...
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what pcb will you use, mike: pot & jack onboard?



Yes, pot and jack onboard
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May 6, 2005 at 9:03 PM Post #366 of 764
The board arrived today and I spent a couple of hours populating it this evening, I've just got to hook up a zobel network and add a few more bypass caps and she'll be ready for casing up.... I was going to take my time building it but I'm missing my WNA so much that I decided to get this one up and running ASAP.

I've gone all polypropylene on this one but will be adding some WIMA polyester caps (220nF) to complement the 220pF EVOX polyprop bypass caps fitted on the underside of the board:

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I'm more of a polyester man myself (kinky
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) and this will be the first polyprop WNA MKll I've made..... it'll be interesting to listen to polyprops in the amp, I hated the polyprop sound in loudspeaker crossovers but they may sound better in an amp (fingers crossed) I love listening to different capacitors and, believe it or not, it was the sonic differences between capacitors that got me into this hobby.... I just love them and am fascinated by them.... great little devices.

The "fine gold" caps look nice, let's hope they sound good too! They looked so good that I decided to rename the "nitai" cap "fine silver" this involved removing the plastic wrap and polishing their butt naked bodies with Brasso and buffing them with a lint free cloth (yeh, call me sad I don't care!) I think they look good alongside the "fine golds":

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Well, the proof of the pudding is in the eating and I will report back with my findings once the amp is up and running.... onwards and upwards, fresh pads to play about with
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The "pictorial guide" won't be happening on this occasion, I'm in too much of a hurry to get another WNA up an running fast and feed my ears with some decent sound.....

Mike.
 
May 6, 2005 at 9:29 PM Post #367 of 764
very nice, mike... also very tempting... rrrgg... must resist....
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the only thingies i don't like in there are those input caps... you know...
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.... maybe your source needs them? hey... the "fine silver" look great!
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May 6, 2005 at 9:57 PM Post #368 of 764
How can you resist? Impossible to resist!! I fit input caps as I use the amp with three different sources one of which adopts a DC servo system..... I prefer the safety net (cap) on board but others prefer no input / output caps....... I'm sending you a couple of bourns 100K trimpots and 10M resistors (as well as a few other goodies to try Udo) let me know how your cap free WNA sounds (I doubt you'll hear a difference)

I'll be trying the capless WNA with my CD-17 in due course but as the WNA is a kit it has to work with "every" source and "every" headphone as a matter of course........ it has to be bullet proof and I am reporting on the kit "as is" (with input and output caps in place) all the mods I have mentioned assume that input / output caps are in the circuit........ Remove the input / output caps at your own risk, the input caps are not necessary if your source has minimal offset but I would strongly recommend you keep to the kit recipe when it comes down to output caps.

I prefer output caps to trimpots they guarantee "nil" DC offset... of course it's up to you and anything you do outwith the recommendation is at your own risk
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Mike.
 
May 6, 2005 at 10:32 PM Post #369 of 764
mike... i've stocked the appropriate 100k precision trimmers and also the 10M resistors some weeks ago. but i have to stick with output caps as long as i'm in the process to try different psus in order to override the railsplitter (just my personal obsession - most likely nothing, that really matters...
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).

but be assured... the difference in sound with vs. without input caps is huge... at least given polyester caps there. drawback: chances are, you'll get some crackling noise while turning the volco...
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but who knows... maybe some decent polypropylene caps (like yours) are the way to go...
 
May 6, 2005 at 10:39 PM Post #370 of 764
Quote:

Originally Posted by BrokenEnglish
but be assured... the difference in sound with vs. without input caps is huge... at least given polyester caps there. drawback: chances are, you'll get some crackling noise while turning the volco...
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DC
 
May 6, 2005 at 11:06 PM Post #373 of 764
my route:
1. psu-tests
2. fit 10m ohm resistors /100k trimmer: if volco-crackling stays, goto 2a
2a. fit 4,7µf mcaps (polypropylene... on their way
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)
3. check the sound without output caps
 
May 7, 2005 at 9:45 PM Post #374 of 764
That's her up and running and I'm so happy to have the WNA sound pampering my eardrums with detail and glorious sound once again
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It's too early to tell but the polyprops seem to give a smoother overall presentation to the sound (compared to polyester) and this really does suit the Grado SR325i.... I'm not sure I like the extra smoothness with the HD-600 but, as I say, It's early days and the amp has only been up and running for about 3 hours.

She fired up first time no problems at all so it really does look like the MKll is pretty much bullet proof and well protected from the oscillation God unlike MKl which could play up from time to time and was pretty sensitive to certain caps and long cable runs.

I decided to keep the internal wiring short and tidy in this amp so didn't fit an On / Off switch or a LED on the fascia..... I keep the amp switched on all the time anyway so an On / Off switch is unnecessary and a fascia mounted LED equally unnecessary. (more wire) I fitted a 5mm LED direct to the board (the LED pads) and will probably cut a hole out of the top cover of the amp and glue in a bit of perspex which will illuminate the amps innards on dark nights:

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The amp looks plain ugly in the Hammond enclosure (or minimalist, whatever you want to call it) and I think a 30mm round perspex peephole in the top would give it a bit of panache.

Ugly or what?

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Thing is, it sounds awesome and that's the main thing..... it's easy to tart up the looks further down the line but the sound is the most important part and boy it's sounding good now (it's been two hours since I started this post and I've been back and forth to the toilet swilling out with ice cold water to alleviate excruciating toothache) I've just popped my 'phones on again and the amp is burning in nicely with the sound opening up and filling out.... Unfortunately the toothache is getting worse and not responding to anything other than 30 second "swills" of ice cold water so I'll cut this thread short and save my energy for a weekend of pain management.

I'll report back on the bypass caps etc. once I can fully concentrate on the amp (once I get this pig of a tooth removed!) In the meantime... MKll seems pretty much bullet proof and plug and play and, as such, gets a big thumbs up from me...... the kit is a breeze to put together and a lot more tidy than the MKl:

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MKll

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MKll

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My first ever WNA MKl (a true wirefest
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)

Things have certainly evolved since the MKl.... let's hope Dr. White continues to hone this fantastic amp, it's a beauty.

Mike.
 
May 7, 2005 at 10:51 PM Post #375 of 764
tight and nice build, mike... as always... i'm sure, besides dr. white there's no one out there who has built more wna has than you. i like your minimalistic approach.... and of course that red led..
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i guess, you've fitted most of the tweaks (330k, qc up)? but i couldn't find the zobel net. i'm sure, you'll spend some coolers to the transistors.

but first of all, mike, i hope you'll cope with that screw*** toothache.... my best wishes!
 

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