Tracing noise problem, TwinRev.

[nosaj]

Yup I did this as I mentioned in #146. I made sure it was placed with room to this cap, made very sure on building it. And as I said I undid screw, took it out, & the noise was not affected/ stayed put. And tested for continuity again when I put screw back in.

We can rule out this screw. But not the cap though. I may as well just replace it as a 'test' as I have no proper cap tester.

Thanks SC

With it on tell me what voltage you have when testing from screw to solder blob . DC volts
nosaj

[Chuck H]

" I would like to answer that question in two ways. Firstly in my usual voice, then in a sort of silly high-pitched whine" ( monty python). Sorry, just reminded me.

Ok. That's funny. I happen to be one of those "cowboys" (read American) that actually like Monty Python's comedy.

But back to business... To clarify, Pete requested that you run the amp with only V1 and V6 in place for the preamp tubes. You noted a volume loss with respect to volume knob setting with this configuration. Does the volume loss with respect to volume knob setting improve for the normal channel with all tubes (including V2 through V5) in place?

[Sea Chief]

Ok. That's funny. I happen to be one of those "cowboys" (read American) that actually like Monty Python's comedy.

But back to business... To clarify, Pete requested that you run the amp with only V1 and V6 in place for the preamp tubes. You noted a volume loss with respect to volume knob setting with this configuration. Does the volume loss with respect to volume knob setting improve for the normal channel with all tubes (including V2 through V5) in place?

Ah ok understand the question now. I did try answering this before, but my answer obviously lost in translation. This just happens with replies.

----

Ok firstly: there's no difference with Normal channel's ( oddly not as loud as it should be ) volume, if the tubes v2,3,4,5 removed.. no change.

Secondly: neeeeeeeoooowwwwwiiiiiiiiiiooooooooowwweeeeeeeeooowwww.

SC

[Sea Chief]

With it on tell me what voltage you have when testing from screw to solder blob . DC volts
nosaj

Hi nosaj, Im reading from this screw to the 'tube-side' solder blob of this disc cap ( that is I believe the HV side ). Reading DC on my dmm.

When I touch the blob with red probe ( the other probe yet to touch the screw) I hear like a 'static click'/ tiny pop. The dmm reads 0.00.

When I then touch the black probe to the screw, the dmm reads 1....... ( I believe open circuit ).

Thanks, SC

[nosaj]

Hi nosaj, Im reading from this screw to the 'tube-side' solder blob of this disc cap ( that is I believe the HV side ). Reading DC on my dmm.

When I touch the blob with red probe ( the other probe yet to touch the screw) I hear like a 'static click'/ tiny pop. The dmm reads 0.00.

When I then touch the black probe to the screw, the dmm reads 1....... ( I believe open circuit ).

Thanks, SC

What does your meter say when you touch the black and the red lead together
nosaj

[nosaj]

[Sea Chief]

What does your meter say when you touch the black and the red lead together
nosaj

0.00

So no idea why you would be asking me this, nor why you would put this clip up = a perfect eg of a failure of you to communicate! ( rather ironic nosaj).

SC

[nosaj]

ReRead this and explain it.

Hi nosaj, Im reading from this screw to the 'tube-side' solder blob of this disc cap ( that is I believe the HV side ). Reading DC on my dmm.

When I touch the blob with red probe ( the other probe yet to touch the screw) I hear like a 'static click'/ tiny pop. The dmm reads 0.00.

When I then touch the black probe to the screw, the dmm reads 1....... ( I believe open circuit ).

nosaj

[Dave H]

Hi nosaj, Im reading from this screw to the 'tube-side' solder blob of this disc cap ( that is I believe the HV side ). Reading DC on my dmm.

When I touch the blob with red probe ( the other probe yet to touch the screw) I hear like a 'static click'/ tiny pop. The dmm reads 0.00.

When I then touch the black probe to the screw, the dmm reads 1....... ( I believe open circuit ).

Thanks, SC

You should connect the ground probe first when measuring high voltage. If the HV side is connected first the ground side probe is at HV. The click and pop are normal. The DMM reads 0.00 with the black probe disconnected so that's its open circuit reading. I think 1....... must be the overrange reading. If the DMM is not autoranging what range was it set on?

[Chuck H]

FWIW I'm having no trouble interpreting SC's post, if that was the issue? With the meter set for DC voltage he touched the red probe to the plate end of the capacitor in question. When he did that he heard a static noise. Then, with the red probe still on that capacitor connection he touched the black probe to the screw and his meter read 1.........

Things I can interpret from this:

SC did not understand the intention of Jason's request and is testing the wrong end of the capacitor. I think Jason is looking for DC leakage at the OTHER end of the capacitor. And...

That 1............ reading on the meter when closing a DC source across the probes is likely indicative of the meter being set to read a lower voltage range and it was over loading or perhaps the meter was set to read resistance in ohms rather than DCV.

EDIT:

I think Jason is looking for DC leakage at the OTHER end of the capacitor.

Or perhaps Jason DOES want a reading at the plate end of that capacitor. Testing for proper continuity or looking for any other possible fault. At any rate I think it would be obvious to test DCV at both ends while SC was in there and then report clearly. Using the meter properly seems to be a necessary missing element though.

[nosaj]

I just wanted to see if we were getting any voltage just leaking back to the fibreboard somehow and the answer given didn't show what what should have happened.
1 is not a correct answer. So I hope if he could explain himself he'd see his error. Perhaps I am the delusional one. But I tire of this game being perpetuated on this forum . I bow out. Nosaj

[Sea Chief]

FWIW I'm having no trouble interpreting SC's post, if that was the issue? With the meter set for DC voltage he touched the red probe to the plate end of the capacitor in question. When he did that he heard a static noise. Then, with the red probe still on that capacitor connection he touched the black probe to the screw and his meter read 1.........

Things I can interpret from this:

SC did not understand the intention of Jason's request and is testing the wrong end of the capacitor. I think Jason is looking for DC leakage at the OTHER end of the capacitor. And...

That 1............ reading on the meter when closing a DC source across the probes is likely indicative of the meter being set to read a lower voltage range and it was over loading or perhaps the meter was set to read resistance in ohms rather than DCV.

EDIT:


Or perhaps Jason DOES want a reading at the plate end of that capacitor. Testing for proper continuity or looking for any other possible fault. At any rate I think it would be obvious to test DCV at both ends while SC was in there and then report clearly. Using the meter properly seems to be a necessary missing element though.

Thanks Chuck. I couldn't possibly have explained any clearer where, & when I put the probes. Just as you understand what I did.

Then nosaj implying Im either not doing something asked for, or cannot read a multimeter, or have it not on DC ( ? Was this his interpretation?), or what i have no idea. Then suggesting I cannot be understood with an ironic clip.... when I cannot understand how he cannot understand what I said- is SO bewildering.

There is no way I could re-write what I did, in any clearer or simpler way. You understand it.

If I am being asked to test a particular end of the capacitor, then please ask me to. But I have said - clear as a bell- which end I tested ((( the HV side. The north side in the pic. The end closest to tubes ))). And the other probe ((( on the screw ))). I mean how can I possibly make this any clearer??? How can this possibly even warrant ' interpretation' ?!!? I've then simply said what the dmm shows. ((( 0.00 :then when both probes on: 1.... )))

How can this not be understood!!??

Thx. SC

[Chuck H]

To be fair the overload reading on your meter DOES indicate that you aren't using it correctly. The 1.......... means there was a voltage at the test point but the meter was not set correctly to register it. But enough about that.

How about you just measure DCV at both ends of the normal channel treble cap. Black probe to the screw or anywhere on the chassis. You should be able to get a reading now that you know about the meter range issue.

[Sea Chief]

To be fair the overload reading on your meter DOES indicate that you aren't using it correctly. The 1.......... means there was a voltage at the test point but the meter was not set correctly to register it. But enough about that.

How about you just measure DCV at both ends of the normal channel treble cap. Black probe to the screw or anywhere on the chassis. You should be able to get a reading now that you know about the meter range issue.

How can I not be using it correctly Chuck?!! To imply Im such an idiot.... is exasperating.

----

One probe here. One there. You understand where these two points are/ where I put them.

I set my DMM to DC. I explain reading with one probe on the cap ( ' click' tiny pop). Dmm reads (( 0.00 ))

I put other probe to screw. It changes, & now reads (( 1.... )) which is open circuit. Nothing registered. Exactly as expected.

----

Please. From what I just typed right here. Tell me how I "have not used it correctly".

Thanks. SC

[Chuck H]

The fact that there was a change in the reading at all when the circuit was closed (both probes in contact with something) means that there was a readable result there. Voltages do not read as open circuits. There is only voltage or not. If your meter was set for DCV as you say then the 1........ reading indicates an over load circumstance for the range setting on the meter. If your meter was set for resistance in ohms (which it should NOT have been) then 1........... means an open circuit.

With me so far?

With the above information reported to be factual by YOU a reading of 1........ means you were using the meter incorrectly in one capacity or another. (<period)