#124 Questions

[Bombacaototal]

Tony

Just came across this video of Paul Reed Smith and he uses your quote of laws of physics and HAD bench

https://youtu.be/BHtpyZNCjdI

It is at 1:58

I wonder what is Paul’s user Id lol

[talbany]

Tony

Just came across this video of Paul Reed Smith and he uses your quote of laws of physics and HAD bench

https://youtu.be/BHtpyZNCjdI

It is at 1:58

I wonder what is Paul’s user Id lol

Thanks for posting that for me!. I changed that comment quite a while ago so it's pretty cool that he still remembers it!

Tony

[Bombacaototal]

Maybe its time to bring that quote back

[Mark]

He does have quite a rant about that guitar yet there isn't a lot said about details of the guitar. The pickups being a prime example.

[talbany]

Maybe its time to bring that quote back

In honor of Sir Paul

[Bombacaototal]

I am a bit puzzled about an issue I am having with the amp which I can by no means fix it.

Whenever I start the amp there is a lot of noise for the first 10 to 20 seconds, and then the noise stops until next time I turn the amp on. I made a recording which is attached.

Any idea of what may be the cause?

[xtian]

What's that loud click at 0:13? Flipping a switch?

Anyway, my new build sounded like that until I figured out I had forgotten the artificial CT for the heaters.

[Bombacaototal]

What's that loud click at 0:13? Flipping a switch?

Anyway, my new build sounded like that until I figured out I had forgotten the artificial CT for the heaters.

Thanks xtian. I did not touch the amp during the recording. That click sound was from the amp itself

By the way my amp has the artificial CT just behind the pilot light

[xtian]

The click was perhaps a relay? At least this is something you can check. Monitor relay coil voltage during startup. Maybe it's taking a long time to get up to spec?

[Bombacaototal]

The click was perhaps a relay? At least this is something you can check. Monitor relay coil voltage during startup. Maybe it's taking a long time to get up to spec?

Thanks for the help xtian. My amp still doesn’t have a relay. But I think you are on the right track as far as something taking long to get to correct spec.

I have a 47n cap across the standby to prevent the pops. I am not sure if this has anything to do with it?

[Bombacaototal]

In the meantime while I try to debug the weird issue at start up I have another question regarding noise floor.

My amp (at Stack -> PI configuration) is dead quiet (as far as noise floor) with master on Max and volume all the way from zero to 3 o'clock. From 3 o'clock until the max of the pot there is an increase amount of hiss which at the max is very loud and sometimes makes the amp get into feedback. Just wondering how this compare to others. And if this is not a normal behaviour what may be the cause.

Just for reference I used to have the LNFB on switch but in the end decided to remove it all together, as I prefer the sound without it.

[martin manning]

The hiss sounds normal to me. You could look for a very quiet tube for V1 if you want to reduce it.

[Bombacaototal]

The hiss sounds normal to me. You could look for a very quiet tube for V1 if you want to reduce it.

Thanks a lot for the feedback Martin

[Bombacaototal]

Back to the grounding topic (which I had in the begining of the Thread). My question is relating to the pre-amp star ground only.

That specific ground star has the buss bar (which is in front of the pots, jacks, etc), the FX Loop jacks (which use isolation washers) and the tonestack supply cap. About the supply cap feeding the Overdrive node, ideally one should add it to the same pre-amp star ground but my question is, would there be any problem soldering it to the buss bar instead (which in theory is the same electronic point). The reasons for that would be (i) lack of stace on the star groundand (ii) proximity of the supply wire to the buss bar vs the star ground.

[Bombacaototal]

Ok, so I tried adding it on the buss and made the amp much noisier.

Therefore grounded back to the pre amp star ground