Help with Interference issue [resolved]

[NightFlight]

After checking your wiring, you might want to attach some sort of open grille / mesh to the bottom of your Crack to prevent little fingers (and big ones) going where they shouldn't.

My son is 5, about to be 6. I simply told him never to touch it, as he could accidentally get a shock and quite possibly die. Explained you have to know what you are doing before you touch it, don't play in this room. Etc.

He gives it a wide birth. 

 

[NightFlight]

Hi There!

I never have more than one connected at a time.

Any chance that your toslink cable for some reason is 'shielded'?
http://www.amazon.co.uk/Horizon-Professional-Performance-Protection-equipment/dp/B005ELLH0W
The above is not shielded, but there's no call for any metal at all on a toslink cable!

Mine is plastic.. cheap cheap cheap. Sears. $5. Works great.

 

[networkn]

My son is 5, about to be 6. I simply told him never to touch it, as he could accidentally get a shock and quite possibly die. Explained you have to know what you are doing before you touch it, don't play in this room. Etc.

He gives it a wide birth. 

My SON is completely safe. He is the most sensible kid and always listens and obeys, I've never had him near a single thing in 4 years which I've asked him to avoid. It's my daughter who is 2.5 who is my primary worry. She will SOMETIMES listen, but sometimes isn't the margin of error I'd accept at 240v

She is getting a little better, but some days she drives me crazy getting into stuff.

 

[networkn]

Any chance that your toslink cable for some reason is 'shielded'?
http://www.amazon.co.uk/Horizon-Professional-Performance-Protection-equipment/dp/B005ELLH0W
The above is not shielded, but there's no call for any metal at all on a toslink cable!

Mine is plastic.. cheap cheap cheap. Sears. $5. Works great.

I have about 6 of them, I'll try some of the others.

 

[networkn]

Okie Dokie. Resistance check has been recompleted after I dropped it.

T1 : 4M
T2: 3M
T3: 0.3ohms
T4: 70K-3.7M
T5: 4-5M
T6: 2.5K
T7: 2.9K
T8: 0 ohms
T9: 2.9k
T10: 2.2K
T12: 0.4ohms
T13: 30M went to 40K then climbed to 270K
T14: 0 ohms
T20: 0.3 ohms
T22: 0.3 ohms
B3: 2.9K
B6: 2.9k
RCA Ground Lug 1 (Black): 0.2ohms
RCA Ground Lug 1: (Red): 93K
RCA Centre Pin 1 (Black): 0.2ohms
RCA Centre Pin 2: (Red): 98k

So the things I wanted to check are:

I did this with the fuse in, but obviously not the power or the tubes, are these results ok ?

RCA results are slightly off 90k but are different? OK ?
Most of the 0 result ones are marginally off, is this ok, or they HAVE to be 0.0 and what should I do if that's the case?
T1 and T2  and T13 OK?

I wanted to do the grounding checks that someone had pasted earlier given the issues I have had with a grounding loop and electrocuting myself (Which I now believe was because I accidentlly touched the IEC and the metal base at the same time.), prior to putting on the power and doing voltage checks.

 

[networkn]

I thought they were ok. Proceeded with Voltage checks.

1: 83
2: 161
3: 1.6mV
4: 160
5: 80
6: Variable
7: 105
8: 1mV
9: 104
10: 5mV
11: 2mV
12: 0
13: 162
14: 0
15: 182
20: 0.5mV
21: 202
A1: 80
A2: 1.8mV
A3: 1.5
A4: 1.9mV
A5: 1.9mV
A6: 84
A7: 0.8mV
A8: 1.64
A9: 1.64
B1: 82
B2: 160
B3: 105
B4: 81
B5: 161
B6: 104
B7: 2.1mV
B8: 2.1mV

OK?

 

[Paul Birkeland]

Looks like you have a working amplifier.

-PB

 

[networkn]

Looks like you have a working amplifier.

-PB

Thanks. What would be the reason for the low numbers instead of 0 at some of the voltage check points like t12?

 

[Paul Birkeland]

5mV is 0.005V, which is pretty close to 0.  This is one of those things that will just vary a bit from meter to meter, as well as from terminal to terminal.

 

[networkn]

Thanks CB.

So a new development. I now have buzzing which exists whether I have a DAC plugged in at all, and only exists after the headphone is about 75% of the way fully inserted in the jack. It seems to have changed and become louder for a few seconds and then went back to a basic buzz. It seems to vary a fair bit and I can affect it by moving around, but not consistently.


Any ideas?

 

[networkn]

Gentle Bump. Sorry guys, you have been so helpful so far, but I just don't know what could be causing the buzzing

 

[Paul Birkeland]

So a new development. I now have buzzing which exists whether I have a DAC plugged in at all, and only exists after the headphone is about 75% of the way fully inserted in the jack. It seems to have changed and become louder for a few seconds and then went back to a basic buzz. It seems to vary a fair bit and I can affect it by moving around, but not consistently.

So, the hum does exist with the headphone all the way in?

Is the amp still quiet receiving music from your phone through a 1/8" to RCA cable?

 

[Doc B]

When you say you can vary it a bit by moving around, what is moving - the amp, parts inside the amp, or you? Usually buzz is from a cold solder joint to ground.

 

[networkn]

When you say you can vary it a bit by moving around, what is moving - the amp, parts inside the amp, or you? Usually buzz is from a cold solder joint to ground.

If *I* Move around (Wave my arms or move closer or further from the AMP)  (Amp and everything else except the headphone cable are static). It's very weird.

The noise from the original topic isn't apparent as best I can tell presently.

 

[networkn]

So, the hum does exist with the headphone all the way in?

Is the amp still quiet receiving music from your phone through a 1/8" to RCA cable?

The Hum Exists with the plug all the way in, but not if it's some of the way out of the plug as best I can tell. (Not sure if you know what I mean but there are stages that the plug will go in). It exists if I remove the RCA Plugs from the Amp completely (As in no source attached.

If there was a cold joint, would this not cause voltage and resistance irregularities?

 

[Paul Birkeland]

The Hum Exists with the plug all the way in, but not if it's some of the way out of the plug as best I can tell.

If there was a cold joint, would this not cause voltage and resistance irregularities?

The only relevant test is with the plug all the way in, otherwise you short some connections together that give you erroneous readings.

A cold solder joint rarely shows up in resistance readings, sometimes will show up in voltage readings, but often enough appears in neither.

My test for a cold solder joint is to jostle the piece of equipment pretty roughly while I'm listening to it.  Cold solder joints will announce themselves with crackling or popping.  Of course, the easiest method to be sure is to reheat all your solder joints.

-PB

 

[networkn]

The only relevant test is with the plug all the way in, otherwise you short some connections together that give you erroneous readings.

A cold solder joint rarely shows up in resistance readings, sometimes will show up in voltage readings, but often enough appears in neither.

My test for a cold solder joint is to jostle the piece of equipment pretty roughly while I'm listening to it.  Cold solder joints will announce themselves with crackling or popping.  Of course, the easiest method to be sure is to reheat all your solder joints.

-PB

When you say piece of equipment I presume you don't mean electronic component? Touching things like capacitors and the like could be pretty dangerous I would have thought?

Given this is a buzzing rather than a crackling is the same solution recommended? Are there some components more likely to be causing that buzzing than others?

 

[Doc B]

You use a non conductive tool to probe and wiggle the components. A chopstick works well. Anything plastic or wood that doesn't have metal on the end can be used to push on the various parts to see if it changes the sound. Use all of the proper safety procedures, support the inverted chassis so it is stable before you apply power, don't touch it with your bare hand.

 

[Horatio]

Bit of a wildcard but I spent two hours last night trying to troubleshoot a noisy Crack (static like buzzing even with nothing connected to it but headphones that I could overcome by cranking up the volume of the music) only to find that it was picking up interference from a Powerline Network Adapter I had plugged into a wall socket in the opposite corner of the room... With the Powerline Network Adapter unplugged everything was silent!

 

[networkn]

Hi There!

I wanted to post back and let you know I am now listening to a silent crack amp, after having given up and taking it to an electronics engineer I found in a local forum.

It took him about 20 minutes to find the problem and only after he went through step by step in the manual did he find that I had connected but failed to solder 2 of the connections on page 19 of the manual (I could get the numbers exactly of which tags, but it's on and would be hot to turn over. He summarized it was allowing a ground loop. It also explained why moving the amp to my office changed the sound as the car movement probably moved the connection slightly.

On the plus side he said with 1 exception he found my soldering to be better than a lot of the graduates with project work experience he had seen, he was pretty impressed.

It was a little frustrating to have it turn out to be this as I had been over the amp at least 20 times looking for bad solder joints but sometimes the more you look the worse it gets.

I am just glad to be over this hurdle. I am trying to now decide if I should listen to it more or move to the Speedball upgrade this weekend.

I am also wondering if there are other upgrades I should add now before the speedball which will be much harder once the speedball is in.