Hello,
here are my diy milled (no CNC) and diy powder coated front plates for the Korg B1 and the S11 PSU
The front plates fits on Modushop cases (230mm/124mm) and are made of an 10mm Modushop front plate I don´t need.
[url=http://abload.de/image.php?img=korgfront011zkex.jpg][/URL]
Kind regards
Andreas
Hi Andreas,
looks nice, S11 PS from D.?
I am really excited about the Xxxx housing from Gerd. ;-)
Have you ensured that PCB has good chassis (ground) connection via the four PCB mounting holes?
Some 3M foam tape on the PCB and mount the Nutube so it is resting on that definitely helps to dampen the vibrations. I also use soft rubber mounting feet on the base of the chassis.
You could also use anti-vibration mounts on the pcb to chassis if it is still troublesome.
But definitely finish it - why give up before you've even heard the magic
you can always sell it on if you don't like it.Yes the chassis is large one with 430x120x300 dimensions and with partition plates to isolate the transformers and PSU boards. I think I have mounted the Korg board on the bottom plate but need to recheck if that is making any contact to the chassis or not properly. Or I will connect one of the mounting legs from the Korg PCB board to the chassis where all my grounding is right now connected. This cabinet also houses the Salas DCG3 preamp which has its own Salas PSU boards with independent transformer. Korg's transformer is a independent one and not being shared with any other board.
Thanks
Hi,
I am finishing up my build from a recently purchased store kit and was in the process of putting in the Fairchild Jfets when I just noticed an anomaly. The matched Jfets came in two bags, one marked Q1, the other Q2. I was getting ready to put in the Q2 Jfets when I noticed that three of them are J112s.
I have no real technical knowledge. I have read the First Watt article, followed this thread and searched it, and looked at the Fairchild technical sheet. I am guessing that this is a problem but really need advice on this.
Thanks.
I am finishing up my build from a recently purchased store kit and was in the process of putting in the Fairchild Jfets when I just noticed an anomaly. The matched Jfets came in two bags, one marked Q1, the other Q2. I was getting ready to put in the Q2 Jfets when I noticed that three of them are J112s.
I have no real technical knowledge. I have read the First Watt article, followed this thread and searched it, and looked at the Fairchild technical sheet. I am guessing that this is a problem but really need advice on this.
Thanks.
That's odd, but not wildly so, as they are just higher Idss than the usual
J113, and there is some overlap there.
Go ahead and use them, they're just constant current sources anyway,
and we are looking for about 6 mA current. You can check that by the
drop across the Source resistors. If the V/R on them is greater than
7 mA, I'll send you replacements.
J113, and there is some overlap there.
Go ahead and use them, they're just constant current sources anyway,
and we are looking for about 6 mA current. You can check that by the
drop across the Source resistors. If the V/R on them is greater than
7 mA, I'll send you replacements.
That bitumen looks like a good idea. Maybe some bubble wrap under the PCB would help dampen it. run rubber band through mounting holes instead of typical rigid standoffs and attached to a hook on the bottom of the chassis. Or just float the chassis on bubble wrap. My friend was once having terrible vibration issues with his turntable in a very high end system. For $10 i build an open bottomed wooden base about 2 inches think and put a bicycle inner tube inside the base and pumped it up slightly. Worked perfectly. So what's the smallest innertube one can buy?
Thanks for the prompt reply. I will be able to check in the next few of days.
Ha, Ha! Audio's best kept secret: bubble wrap for vibration control. I once proposed that somebody should brand it and sell it for $500 a square foot.
It lives!
Well, after a couple of false starts and some smoke (turns out wiring up the DC socket correctly is important) I have sound, I'm thrilled.
No indication of any microphonic issues (at low listening levels); I have the Nutube sitting on a 3M sticky foam pad. The Lego case is currently sitting atop a 30 duro (very soft) Sorbothane pad which will go inside a more permanent enclosure which is in the works, with the PCB sitting on top on plastic stand-offs.
Next steps - thinner gauge wire; save up for a shunt attenuator; try Charcroft Z-foil 100 Ohm output resistor; add second input and toggle switch; add power on / off rocker switch.
Sounds great at 9.5v and phase corrected at speaker terminals - I'll hook it up to a distortion analyser and experiment with different values.
I narrowly missed a pair of Cinemag output transformers on flea bay - maybe this is something to try to correct the phase before a headphone amp.
What a ride it's been!
Well, after a couple of false starts and some smoke (turns out wiring up the DC socket correctly is important) I have sound, I'm thrilled.
No indication of any microphonic issues (at low listening levels); I have the Nutube sitting on a 3M sticky foam pad. The Lego case is currently sitting atop a 30 duro (very soft) Sorbothane pad which will go inside a more permanent enclosure which is in the works, with the PCB sitting on top on plastic stand-offs.
Next steps - thinner gauge wire; save up for a shunt attenuator; try Charcroft Z-foil 100 Ohm output resistor; add second input and toggle switch; add power on / off rocker switch.
Sounds great at 9.5v and phase corrected at speaker terminals - I'll hook it up to a distortion analyser and experiment with different values.
I narrowly missed a pair of Cinemag output transformers on flea bay - maybe this is something to try to correct the phase before a headphone amp.
What a ride it's been!
Attachments
You couple signal to a 10 kohm in series with the output pin off your pot this will make it a shunt pot.
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LOVE the Lego chassis! A favourite toy/past time when I was a child. Still love building basically anything with my Son using Lego.
I have a Raal 140-15D ribbon driver with a built in ribbon transformer so that the amplifier doesn't see 0 ohm. It acts like a coil in the crossover so I just have to add a cap to get a 2nd order passive crossover. But how do I reverse poles on a Raal that has this built in transformer/coil without screwing up the passive crossover?
Lots of love for the Lego. Took me about 45 mins using whatever was in the box. I'm thinking about upgrading some of the bricks to Tantalum though.