Express Hiss Issues

[Roe]

the wire from the presence pot to the ground is noisy when touched unless the back of the pot get grounded as well

problem solved. wire to the wiper and the .1uf were slightly microfonic. I also had a presence squeal caused by a microfonic bright switch

[rooster]

OK, your use of terms is all wrong here. 'Star Ground' means a single ground for all components. ...See what I mean? So you can't have 6 'Star Grounds'.

You have installed a multi-ground path system in your amp. OK?

Also, I don't know who Larry is, and I really don't think he should be credited with the ground system here. Afterall, if you look in the Express Build Guide, you will see a better interpertation of a multi-path ground system by Alan Phillips. ........And his is excellent. Neither one of them 'invented' it, BTW. Too, when you do the homework, there is not an expert out there who will NOT tell you that skipping the center tap of the filament coil - and using instead either a 100-200 ohm pot to ground for minute balancing or the typical 100 ohm X 100 ohm resistor to ground for the 3.3 VAC leads - is better for less noise in the circuit. ......Which is interesting because it looks like you used the filament center tap. See what I mean? If Larry is reccomending the use of the center tap here, he is, eh, not aware. KF knew this and used it in his builds. Again, see what I mean?

Any, if you are happy with your changes, cool.

[Roe]

OK, your use of terms is all wrong here. 'Star Ground' means a single ground for all components. ...See what I mean? So you can't have 6 'Star Grounds'.

You have installed a multi-ground path system in your amp. OK?

Also, I don't know who Larry is, and I really don't think he should be credited with the ground system here. Afterall, if you look in the Express Build Guide, you will see a better interpertation of a multi-path ground system by Alan Phillips. ........And his is excellent. Neither one of them 'invented' it, BTW. Too, when you do the homework, there is not an expert out there who will NOT tell you that skipping the center tap of the filament coil - and using instead either a 100-200 ohm pot to ground for minute balancing or the typical 100 ohm X 100 ohm resistor to ground for the 3.3 VAC leads - is better for less noise in the circuit. ......Which is interesting because it looks like you used the filament center tap. See what I mean? If Larry is reccomending the use of the center tap here, he is, eh, not aware. KF knew this and used it in his builds. Again, see what I mean?

Any, if you are happy with your changes, cool.

sorry, multi ground system may be a better term than 6 "star ground".
I didn't say that Larry invented this. I just gave it a name by referring to one of its proponents.

I am very happy with how it works

[camden_guitarist]

Hi everybody,

Thanks a lot for all your input. As stated I just experience lots of hiss, that does get louder the more I turn the amp up, how can I measure (as Glen did in mA) the amount of hiss??? I'm a newbie so bear with me here.

I do use the Hotplate to attenuate it and on the -12dB point you can't really hear a lot of hiss anymore, but I was just wondering what might cause it. If any solderjoints would be bad I'd also have hum no?

Anyway, again, thanks for all your input.

Cheers,

Paul.

['67_Plexi]

OK, your use of terms is all wrong here. 'Star Ground' means a single ground for all components. ...See what I mean? So you can't have 6 'Star Grounds'.

You have installed a multi-ground path system in your amp. OK?

Also, I don't know who Larry is, and I really don't think he should be credited with the ground system here. Afterall, if you look in the Express Build Guide, you will see a better interpertation of a multi-path ground system by Alan Phillips. ........And his is excellent. Neither one of them 'invented' it, BTW. Too, when you do the homework, there is not an expert out there who will NOT tell you that skipping the center tap of the filament coil - and using instead either a 100-200 ohm pot to ground for minute balancing or the typical 100 ohm X 100 ohm resistor to ground for the 3.3 VAC leads - is better for less noise in the circuit. ......Which is interesting because it looks like you used the filament center tap. See what I mean? If Larry is reccomending the use of the center tap here, he is, eh, not aware. KF knew this and used it in his builds. Again, see what I mean?

Any, if you are happy with your changes, cool.

sorry, multi ground system may be a better term than 6 "star ground".
I didn't say that Larry invented this. I just gave it a name by referring to one of its proponents.

I am very happy with how it works

Yes you can, a bolt with 4 or 5 terminals on it looks like a star, there are several of them, therefore 'multi' is a pretty good word choice and they all connect to ground. So putting it all together you have a multi-star ground. I was going to call it a constellation ground, but we might run in to trademark issues with that. How about we call it a multi-sunflower ground instead. There, no-one can argue with that.

[rooster]

Alan - Cool, you are visiting. Well, wait a minute, he was saying that he had different ground points throughout the chassis, not all located at one central point. What do you call this, then? That's what I was going for.

BTW, how's things? I enjoyed the JB interview in GP and glad to see you got a nod. I will still say his youtube video is devoid of a 'clean gtr' sound even though he keeps using the words.... But it is a relative thing for sure.

[Roe]

OK, your use of terms is all wrong here. 'Star Ground' means a single ground for all components. ...See what I mean? So you can't have 6 'Star Grounds'.

You have installed a multi-ground path system in your amp. OK?

Also, I don't know who Larry is, and I really don't think he should be credited with the ground system here. Afterall, if you look in the Express Build Guide, you will see a better interpertation of a multi-path ground system by Alan Phillips. ........And his is excellent. Neither one of them 'invented' it, BTW. Too, when you do the homework, there is not an expert out there who will NOT tell you that skipping the center tap of the filament coil - and using instead either a 100-200 ohm pot to ground for minute balancing or the typical 100 ohm X 100 ohm resistor to ground for the 3.3 VAC leads - is better for less noise in the circuit. ......Which is interesting because it looks like you used the filament center tap. See what I mean? If Larry is reccomending the use of the center tap here, he is, eh, not aware. KF knew this and used it in his builds. Again, see what I mean?

Any, if you are happy with your changes, cool.

sorry, multi ground system may be a better term than 6 "star ground".
I didn't say that Larry invented this. I just gave it a name by referring to one of its proponents.

I am very happy with how it works

Yes you can, a bolt with 4 or 5 terminals on it looks like a star, there are several of them, therefore 'multi' is a pretty good word choice and they all connect to ground. So putting it all together you have a multi-star ground. I was going to call it a constellation ground, but we might run in to trademark issues with that. How about we call it a multi-sunflower ground instead. There, no-one can argue with that.

yes, multi-sunflower sounds good
the idea is to use 6 different grounding bolts, one for each stage in the HT power supply

[rooster]

Alan - See what you did?

[rooster]

.............And oh, to bite this off somewhere near the umbilical cord, here's a definition from R.G.Keen regarding 'star ground'. I accept it is as accurate and representative of the subject matter, although again, he did not invent it and there are many people who can be quoted identically, or thereabouts.


<<< "OK, so what's "star grounding" really mean? How do you do it?

Simply put, star grounding means that you designate some special terminal as the "Star Ground" for the system. All other "grounds" will be referred to this one point. Then *every single place* that is connected to ground in the whole box has its own separate wire run to the Star Ground point. The ground wires radiate away from the Star Ground in all directions, hence the name. This has the unfortunate result that you may have a HUGE number of wires coming into the Star Ground point. Very hard to wire, just because of the large number of wires." >>>>


So Alan I know you can build great amps, and hence you can call something anything you like as far as I'm concerned. But still, there is a definition of 'star ground' that is shared by many EEs and amp builders. Are you wishing to blur the accepted defintion of something amp related and have some fun perhaps? Ah, that wicked sense of humor is always a force to be considered, I understand. Man, you have hung out with EJ too long. Take care.

[rooster]

Alan? Lost you, I guess.

As to hiss, here's some live sound clips done using a little hand held Roland R1 recorder this past Friday. No, I did not add any verb, that's the room. This is not studio stuff by any means, but my point here is that for an amp that can do what this thing does, well, if there's hiss then I will deal with it.

['67_Plexi]

.............And oh, to bite this off somewhere near the umbilical cord, here's a definition from R.G.Keen regarding 'star ground'. I accept it is as accurate and representative of the subject matter, although again, he did not invent it and there are many people who can be quoted identically, or thereabouts.


<<< "OK, so what's "star grounding" really mean? How do you do it?

Simply put, star grounding means that you designate some special terminal as the "Star Ground" for the system. All other "grounds" will be referred to this one point. Then *every single place* that is connected to ground in the whole box has its own separate wire run to the Star Ground point. The ground wires radiate away from the Star Ground in all directions, hence the name. This has the unfortunate result that you may have a HUGE number of wires coming into the Star Ground point. Very hard to wire, just because of the large number of wires." >>>>


So Alan I know you can build great amps, and hence you can call something anything you like as far as I'm concerned. But still, there is a definition of 'star ground' that is shared by many EEs and amp builders. Are you wishing to blur the accepted defintion of something amp related and have some fun perhaps? Ah, that wicked sense of humor is always a force to be considered, I understand. Man, you have hung out with EJ too long. Take care.

I was just being ironic. However, multi-star does explain the ground scheme pretty well. At the end of the day there's only one ground in every amp, the chassis, it's how you have current flowing through various parts of that that matters.

['67_Plexi]

.............And oh, to bite this off somewhere near the umbilical cord, here's a definition from R.G.Keen regarding 'star ground'. I accept it is as accurate and representative of the subject matter, although again, he did not invent it and there are many people who can be quoted identically, or thereabouts.


<<< "OK, so what's "star grounding" really mean? How do you do it?

Simply put, star grounding means that you designate some special terminal as the "Star Ground" for the system. All other "grounds" will be referred to this one point. Then *every single place* that is connected to ground in the whole box has its own separate wire run to the Star Ground point. The ground wires radiate away from the Star Ground in all directions, hence the name. This has the unfortunate result that you may have a HUGE number of wires coming into the Star Ground point. Very hard to wire, just because of the large number of wires." >>>>


So Alan I know you can build great amps, and hence you can call something anything you like as far as I'm concerned. But still, there is a definition of 'star ground' that is shared by many EEs and amp builders. Are you wishing to blur the accepted defintion of something amp related and have some fun perhaps? Ah, that wicked sense of humor is always a force to be considered, I understand. Man, you have hung out with EJ too long. Take care.

I was just being ironic. However, multi-star does explain the ground scheme pretty well. At the end of the day there's only one ground in every amp, the chassis, it's how you have current flowing through various parts of that that matters.