[bscholz]

Hi, all.
I'm new to this forum and really just a "follow-the-instructions" kind of guy who likes to listen to vinyl, not an electrical engineer.  Anyway, last year I had built a Bugle and was running it off 9V batteries. But I was curious to know how much better this already impressive preamp could sound, so I decided to build the Power supply as well. I found the overall design and manuals pretty easy to follow...until I got to the part about powering up the Bugle PS and connecting it to the preamp. I really needed more help than the manual provided so I reached out initially to Jack (jcg0322), who was kind enough to forward me some instructions he had put together. But once again, I am too much of a beginner to figure out basic things like whetehr to connect the positive or negative power source to a fuse, or how to properly wire a switch.

I have tried to diagram what I think I should do as far as connecting power, etc. to make my Bugle run off 12V, but I (and probably every other newbie who found himself in over his head) would appreicate it if some of the more knowledgeable people on this board would review my plan and let me know if it is correct, or what I need to change.  I really don't want to blow this project up after investing so many hours in it. In particular, I am not certain about whether I have the switch (an illuminated rocker switch -- part # CL102J9GS205QA7 from Mouser) located and wired properly in the circuit. Also not sure if I have the power connecting to the proper points on the circuit board. There are two holes at each of the 115V inputs on the PCB, and I don't know if it matters which one I connect the power leads to.

If anyone is willing to review/comment on the semi-schematic, I'd be really grateful.

[hagtech]

The switch wiring doesn't look right.  Seems as if when you turn it on the LINE and NEUTRAL will be shorted.  And there should be no reason for EARTH to go to it.

If the LED has separate wiring from the mains, you could simply connect it to the LED+ and LED- terminals on the power supply board. 

jh

[bscholz]

Thanks, Jim. Can you tell me what part of the switch wiring appears wrong, other than not needing to ground it? (Remember, I have little background in electronics.)

Another thing I noticed when I used a multimeter on the switch is that the diagram I got from the data sheet appears to be wrong or else I am misreading it. When I measured resistance between pins 1 and 2, I got “0” when the rocker is lowered on the R side and raised on the L (looking at the side with the pin numbers). This would seem to indicate that this is the correct “on” position, although the diagram inidcates that this would be off. Flipping the rocker the other way, I get infinite resistance. 

[poty]

I think a wire from the Line of IEC socket should go to fuse, from another contact of the fuse to pin 1 of the switch. Pin 2 should be connected to a 115V input of the power supply. Neutral from IEC should go to another 115V input of the PS board and another wire should go to pin 3 of the switch. Please make sure you understand the pin numbers correctly! The switch is illuminated by a neon lamp, so you cannot connect the light to the LEDs output of the power supply.
There must be some mis-wiring in the powering the Bugle PCB. I can't say for sure how this should be done, because I'm on vacation now and cannot access all the documents, but sure somebody should be able to help you with this problem. Additional thought: do you have already the on-off switch installed on the board (Bugle)? If not - corresponding pins should be shorted out permanently by wires.

[Speedskater]

The Ground pin on the IEC jack should connect to the chassis near the IEC jack.
The Ground connection on the pre-amp board should connect to the chassis near the RCA I/O jacks.

[Speedskater]

Any AC power wires inside the chassis should be dresses (routed) as a twisted pair.

[bscholz]

Here is the revised diagram...

[bscholz]

So, based on what you guys have told me so far, I revised the diagram (above). Is this closer to what I need to do?

Poty: you mentioned that "another wire should go to pin 3 of the switch." I was unsure what wire you were talking about, so I figured maybe it was a neutral wire from the AC supply which -- in my current diagram -- then continues on from pin 3 to the power supply board.  Also, in answer to your question, I did install the switch on my Bugle and am planning to leave it in place.

Speedskater: Is there any reason why I can't ground the IEC connector and the preamp board to the same grounding point on the chassis?

Thanks, all, for your help so far!

[bscholz]

Not sure if this helps, but here is the schematic for the lighted rocker switch:

[poty]

Poty: you mentioned that "another wire should go to pin 3 of the switch." I was unsure what wire you were talking about, so I figured maybe it was a neutral wire from the AC supply which -- in my current diagram -- then continues on from pin 3 to the power supply board.

Electrically speaking you understand me right, but the neon lamp is a source of noise, so I'd prefer to connect the power supply board directly to IEC socket (I mean connect the other end of the neutral wire going from the power supply board to IEC neutral, not to pin 3 of switch as you show on your diagram). If you can afford you can include a small AC mains filter between the IEC and the power supply board.Of course the filter is not an essential part and you can easily add it further if you have any issue with noise.
About grounding... Turntable usually has a ground connection to a phono amplifier. The ground connector in the Bugle then is necessary. I'd prefer to use the ground connector as the single point of grounding. It (the connector) is not isolated from the chassis, so it would serve as the safety grounding, shield grounding, turntable grounding and circuit grounding. But it is only my opinion.
According to the 15V connection. You should swap wires going from -15V and GND to the battery holes (-15V pin from the power supply board must go to minus battery hole to the Bugle board; corresponding GND from the power supply board should go to plus hole on the Bugle; It is possible to connect only one GND (and sometimes preferable).

[Folsom]

I'd "star ground" as well. (ground from turntable and earth ground connecting in the same spot to the chassis.) Hopefully it's easy to organize it with the IEC near by. That's what I did with mine.

The transformer I found to be the most confusing part. It took me a second looking at it, and it is not my first power supply wiring I've done.

[poty]

I see the connections the following way:



The diagram is for 115V.

[hagtech]

Yeah, follow the diagram from poty.

jh

[bscholz]

Poty -- Sorry to be so long in responding (I was on vacation last week), but thanks so much for your diagram; this is exactly what I needed! I had already started assembling things before I saw your post, so I have a couple of questions. I have attached a photo of my progress to date to give you an idea of what I've done. (Please ignore the IEC ground being connected to the outside of the case; this is a temporary thing until I put another grounding post in the chassis.)

1) I am using spade connectors at the power inlet. Can I simply crimp two wires into the connector at the negative terminal then run one to terminal 3 of the switch and the other to the power supply board?

2) When I read your power connections to the Power Supply Board from top to bottom, you have Hot/Neutral/Hot/Neutral. Mine is currently wired the exact opposite (i.e., Neutral/Hot/Neutral/Hot). Should I rewire or does it not matter? Since I used spade connectors, it's not a big deal to rewire; I can just swap the hot an neutral connections at the IEC. But then my anal-retentive gene will kick in and I'll be forever bothered by the fact that I have a black wire as hot and a red wire as neutral

3) I noticed you eliminated the PSB ground to Battery 2 negative connection. Does it matter if this is connected or not? (Mine currently is.)

4) You mention insulating the RCA shells from the case. The ones I installed have a thin plastic ring on the outside of the chassis. Is this what you mean? Or do I need to add another plastic ring where the jack touches the inside of the chassis?


I must say, this project has been a very satisfying introduction to electronics but I wouldn't have gotten this far without the amazing help of everyone on this forum. Thanks to you all!

 

[poty]

1) I am using spade connectors at the power inlet. Can I simply crimp two wires into the connector at the negative terminal then run one to terminal 3 of the switch and the other to the power supply board?

Yes, you can.

2) When I read your power connections to the Power Supply Board from top to bottom, you have Hot/Neutral/Hot/Neutral. Mine is currently wired the exact opposite (i.e., Neutral/Hot/Neutral/Hot). Should I rewire or does it not matter?

It does not matter at this stage.

3) I noticed you eliminated the PSB ground to Battery 2 negative connection. Does it matter if this is connected or not? (Mine currently is.)

It does not matter.

4) You mention insulating the RCA shells from the case. The ones I installed have a thin plastic ring on the outside of the chassis. Is this what you mean? Or do I need to add another plastic ring where the jack touches the inside of the chassis?

Any metal part of the RCA should not touch the chassis. I can't clearly learn from you description if the rule is been followed.

[bscholz]

Well, I finally finished assembling my Bugle and Power Supply and I just wanted to thank everyone on this board who provided such generous assistance. Remarkably, my build passed the smoke test and the readings I got at the + and -15V connection points at the Bugle were very close to ideal (from my perspective): 14.92 and 14.95. Most important, the preamp sounds great! I was using the phono input on a vintage Marantz 2240 before and, while I liked many of its qualities, it had developed a slight but annoying hum. (That's my next project.) After plugging the Bugle into the Marantz AUX, I was amazed at how detailed and clear the sound is. Count me as another happy Bugle customer.

Based on the advice I received here, my approach to isolating the RCA inputs from my metal chassis was this: I wrapped a very thin piece of silicone tape around the connector where it entered the chassis to keep it from contacting metal-to-metal. I used the color-coded plastic washer that came with the jack at the outside entry point, and fiber washers picked up at ACE hardware to isolate the inside of the jack, where the nuts attach it to the chassis. Overall, it seems to work.

I've attached a couple more pics of the final build before I attached the cover.

Thanks again to everyone for your help.