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PostPosted: 20 Feb 2009, 18:16 
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Well, Gio, it appears that the trannies sent with the K-12G kit are the same as in my K-8LS kit. Hopefully this does not bode badly for the sound of the K-12!

In the next day or so I will post my layout for the K-12 amp. I spent a bunch of hours mapping connections and have created and loaded up a turret board with resistors and capacitors. My tubes and input/output jacks will be mounted directly to the chassis and wired to the turret board.

PCBs are wonderful things, I think. My K-8 kit went together in an hour or two, but the result is a bunch of components flapping in the breeze. It looks juvenile! Plus, the PCB-mounted jacks and volume control are downright flimsy. And, as we know, the results are unimpressive.

I don't know how PCB "traces" are rated in terms of wire gauge. I figure it's pretty minimal. I'm using 22ga. teflon-coated wire to hook things up, and hope it makes a difference.

One more thing: the wires on the OTs in the K-12 kit exit from the top, which is inconvenient for a chassis mount. I removed the "guts" of the trannies and rotated them so the wires exit downwards. I also painted the trannies with black paint to make them look a bit more elegant.

Watch this space!
Lofton


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PostPosted: 21 Feb 2009, 16:17 
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connemaraguitars wrote:
Well, Gio, it appears that the trannies sent with the K-12G kit are the same as in my K-8LS kit. Hopefully this does not bode badly for the sound of the K-12!

I doubt that is the problem with the S-5 Electronics K-8LS Tube Amp Kit.

connemaraguitars wrote:
I don't know how PCB "traces" are rated in terms of wire gauge. I figure it's pretty minimal. I'm using 22ga. teflon-coated wire to hook things up, and hope it makes a difference.

Here is a chart showing the various American Wire Gauges (AWG) for sizes, current and resistance. Your heater draw is 0.45A, so 22ga should be fine.
I'm looking forward to your results.

Cheers

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PostPosted: 24 Feb 2009, 22:32 
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Yay !

I just ordered one of these kits too - I was looking at getting one over a year ago and became distracted with too many other things - I am hoping that this will be a fun little tube project that may inspire me to design some of my own.


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PostPosted: 24 Feb 2009, 23:07 
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;) It was for me!

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PostPosted: 25 Feb 2009, 10:55 
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It should really get the juices flowing.

I have not built one but I heard one at my first GTG and it was a very good rival for a quality T-amp. Couple that with ease of building, the cool look of tubes, and easy upgrading...if you don't catch the bug there is a good chance you are immune. :up:


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PostPosted: 25 Feb 2009, 18:52 
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Here's a brief update...

My turret board is complete and all components have been installed. I bought a nice piece brass for the cabinet top (to which the tubes and trannies will be attached).

Yesterday I upgraded my copy of TurboCAD so I can create a layout...when done (tonight or tomorrow) I'll post it for comments.

It's easy to see why PCBs are so popular...they save a huge amount of time and suffering. On the other hand, I wonder whether point-to-point wiring might give better results tthat offset the added effort. I cut my teeth on guitar tube amps which used either eyelet boards or turret boards; when I got the K-8 kit I thought, "gee this is too easy...how good can it sound?" Since, as we know, that kit gives less than stellar results, maybe I got caught up in the idea that the PCB was part of the problem...hence my (potentially misguided) decision to not use a PCB for the K-12 kit.

Then again, maybe I have this crazy notion that DIY shouldn't be too easy, and using a PCB is too much like making brownies from a mix.

On a side note, I think I'm going to apply the K-12 mods to my K-8 kit and see if they make a difference.


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PostPosted: 25 Feb 2009, 19:10 
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Post pictures when you get a chance. Aside from making for simple work, a PCB with good layout can make for very short paths can be quiet.

Bruce went to town with the K-8LS kit and could not get it to sound good. Now this has got me wondering about the iron. I guess we will find out soon enough. I'll email Bruce and ask him if he tried the K-8LS iron elsewhere.

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PostPosted: 25 Feb 2009, 19:38 
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Good thing edcors are nice and cheap and sound tremendous.


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PostPosted: 25 Feb 2009, 19:50 
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I got a response back from Bruce, here is the email exchange:

Gio wrote:
BTW - did you ever try you K-8LS output iron in a different circuit to eliminate that as the problem. Seems the new K-12G kits come with the same K-8 iron and this has us wondering.

Bruce wrote:
My K-8 (after I got on their case) came with the same trannies as the K-12. I believe it was a bad choice of tubes for that circuit. No one item bad, just a patch up job on their part. They got a batch of tubes that were similar in spec to the original and stuck them in the circuit. Maybe never checked to see what they actually did. According to S-5 at the time the new ones and old ones are the same spec, just the manufacturer built them sideways. My amp when I tested it had the old style transformers. Worst performing amp I have ever seen.

So that should eliminate the iron from the equation.

:cop: Further discussion about the K-8LS split to: Salvaging the S-5 Electronics K-8LS Tube Amplifier Kit.

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PostPosted: 28 Feb 2009, 17:27 
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My attempts to create a turret board for the K-12 have been, well, embarrasing. I will post a photo later, but suspect I may be in a "do over" situation.

Never having created a layout from a schematic, I missed a number of things that I guess only experience can teach. Fortunately, the cost of the process is low, as the expensive components are salvageable.

I've built amps from layout diagrams up to this point: a couple of 5E3s, a low-power Fender Twin, and Dave Hunter's Two-stroke. So far my success rate is 66%...the 5E3s turned out well and the Two-Stroke has been a disaster; the Twin is not done due to a lack of funds for good transformers, so I don't consider it a failure yet.

It seems that the goal of any layout is to keep leads (wires) as short as possible. When all is said and done, I hope to be able to create a primer on translating schematics to layouts...assuming I can get this right! For fun, I ordered enough components to build two more K-12s, so keep watching, if patience allows!

Thaks for all the encouragement and support, folks!
Lofton


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