Greetings... and a question about the Bugle phono stage

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NorCalAudio

Hello all, I am in the process of building a simple Bugle phono stage using the 15volt PS. I have built these into 2 separate 6 X 3.5 X 2.5 enclosures. I have finished the PS, and it works great. The output is right at +14.871 / -15.003. I built an umbilical style power cable that runs to the phono stage.

I have both units assembled and up, but I am having some problems. The output is not right. Both channels sound terrible and grainy and sometimes pop. I am sure something is not right. When I was stuffing the Phono board my iron was not holding temp. I had to turn it way up to even get it hot. I know I soldered some of those caps with too much heat, but I was quick. Anyhow I have rechecked all resistor values and they seem good. I have looked into the grounds and I have each case grounded through a common ground going to the green ground on the power supply. In the pic I have the inputs and output RCA jacks not mounted in the chassis as I try to figure out what my issue may be.

So far I have checked the resistor values, power supply voltages at the phono stage and DC output voltage (Didn't want to fry downstream equipment). These all seem to check out ok. I am looking for other ideas and pointers.

Any ideas and advice is greatly appreciated, thanks in advance.
Pat








NorCalAudio

Re: Greetings... and a question about the Bugle phono stage
« Reply #1 on: 10 Nov 2010, 09:30 pm »
I went back through all the solder joints and found a couple cold joints. Hooked it all back up to the power supply and looked at the voltage coming into the phono stage. I noticed that the voltage is climbing on one side and decreasing on the other side. Voltage leaving the power supply is a constant +15.04 / -14.97 but the voltage at the other end (Bugle) starts off +15.04 / -14.97 but one side starts climbing and the other drops. I went through the connections and grounds and don't see what I did (or didn't) do.

Any insight is much appreciated, thanks
Pat

NorCalAudio

Re: Greetings... and a question about the Bugle phono stage
« Reply #2 on: 11 Nov 2010, 07:56 pm »
Well, I got my power supply problem sorted out, thanks, Jim. I am now trying to get the right channel working. I barely have anything coming out of the right channel.

hagtech

Re: Greetings... and a question about the Bugle phono stage
« Reply #3 on: 14 Nov 2010, 04:51 am »
Add insulators to the RCA jacks.  Don't let shield touch chassis on inputs.  You will get hum.

jh

NorCalAudio

Re: Greetings... and a question about the Bugle phono stage
« Reply #4 on: 14 Nov 2010, 05:09 pm »
Thanks Jim, I was waiting on the insulated RCA jacks to arrive so I used the pigtails in the photo to get everything shaken out. I found that one of the Caps, C3 was the problem. I could not get it soldered in tightly so I replaced it with an extra one I had ordered. Voila, done. Both channels are even and clean.

It is now finished and being used. I have left 2 extra holes on the back for two RCA jacks that can be used for tunable resistance for each channel. I just have to figure out how to implement.

Thanks for your work and support Jim.

hagtech

Re: Greetings... and a question about the Bugle phono stage
« Reply #5 on: 9 Dec 2010, 07:13 am »
I like the chassis you found.  Where did you get it from?

jh