Herbert Hum Trimmer?

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Hello! Was just reading the forums and lots of old posts and was reading about the hum trimmer. I'm sure my Herbie is noisier than it should be. I posted about this before and people seemed to just suggest tubes. I tried swapping various ones in and out since then and it didn't seem to make much/any difference. It blew plenty of tubes back in the past and the forum seems to suggest this could damage the hum trimmer. It seems to suggest this might be to blame as I'm sure it was near silent once upon a time. It seems to suggest that replacing the hum trimmer with 2 fixed resistors is a good idea. That was mostly VH4 posts though. Is this true for the Herbert or just the VH4?

BTW, don't worry, I used to solder stuff in mobile phones, I'm sure I won't bugger up large through-hole components if this is a good idea! :thumbsup:
 
I have read alot of threads about this. I really want some clarification on what people think is "noisy" My herbert has a light hum when it's on and the volume on my guitar is down and the volume on the amp is up. It also has a very light hum when the volume on the amp is turned all the way down. I've tried adjusting the hum trimmer but no changes occurred... What kind of "noise" are we talking about?

-Alex
 
It´s just on the VH4.

A 180 watt power amp is "noisy" in your bed room.
That´s concering the big transformers.

High gain is also noisy and is causing hiss. You can
decrease the hiss with good tubes.

At the average we have no noisy amps without
using internal noise gates which will decrease the
quality of signal flow.

Please advice.

Best,
Peter
 
Peter Diezel":7khr819y said:
It´s just on the VH4.

A 180 watt power amp is "noisy" in your bed room.
That´s concering the big transformers.

High gain is also noisy and is causing hiss. You can
decrease the hiss with good tubes.

At the average we have no noisy amps without
using internal noise gates which will decrease the
quality of signal flow.

Please advice.

Best,
Peter
Click to expand...

Thank you Peter. That is exactly what I thought. It was good to get some clarification on it! I never notice the hiss when I'm playing a show and it's never caused any problems when recording and that's all that really matters.

-Alex
 
Mended it! There was an old random preamp tube I'd had in it from where a Ruby went dead ages ago. It seemed to have gone noisy. I swapped the tube and fixed the problem last night, but by then it was late so spent the next 10 minutes before bed standing too close to the amp worrying about it. Magnetic emissions was making my guitar hum then and I though it was still hummy, but I'd actually fixed it! Old JJ for the bin and smiley face! :)

Nope, noise gates never go near this! Spoil my Diezel attack? Not likely! :)
 
Me":1yhcbjpd said:
Nope, noise gates never go near this! Spoil my Diezel attack? Not likely! :)
Click to expand...

I use a ISP decimator at band practice and live. I don't turn it up high enough to choke down the hum just enough to make the "stoppy" parts pop out and sound tighter. Doesn't hurt my sustain or attack at all. Really awesome pedal for that! It's a needed effect for metal ;)

GLAD YOU GOT YOUR HERBERT FIXED!!!

-Alex
 
I decided to take it out the case as I figured it could do with a very very very(!) careful clean in the top because it's got a bit dusty in there since 2007 so occasionally it smells of hot dust and also I want it to look nice and clean, especially as hopefully I'll be getting a shiny new cab for it soon too! I thought I might tweak the hum trimmer slightly just for peace of mind and to see if it did hum a tiny bit less as a by-product, or show it was best already, even though I'd consider it a lot "better" now I swapped out that preamp tube. Just wanted piece of mind because it had blown power tubes a few times in the past and I read various posts on here about them getting damaged.

The hum trimmer doesn't do anything?!?!? AT ALL!!! It doesn't get any better but it doesn't get any worse at all either! No matter where I turn it! :confused: Is that normal? Or is there something wrong with it? I assumed it'd get worse and I'd end up putting it back where it was, but at least I'd have peace of mind. I know this has something to do with adjustment of the heaters. Is there any possibility my current tubes have un-humming heaters regardless of the setting? Or is it duff after all and Herbie should hum slightly less if it worked? My sanity check for peace of mind seems to have done the opposite. :doh:

That's done with guitar plugged in, amp warmed up and connected to cab, switched on, and volume about 11 o'clock. Didn't want to turn it any higher in case it pops and wakes up the old woman next door! Or to you have to do it at higher volume? Tha seems the right way to check from the other forum posts I researched.

More thoughts...

If it's any help it measures 1.1Ω across the 2 legs (with the amp off and the trimmer in about the middle). So basically a short. The suggested replacement resistors in the other posts suggested it should be 150-200Ω across it (47-82 Ω + 100 Ω), but obviously this is soldered in so is in parallel with anything else in the circuit at that point so I don't really know. I didn't think I could get to the wiper, but I can actually. Seems that varies the resistance from the wiper to the other end from 0Ω to 25Ω in the centre and back to 0Ω again. So maybe it's supposed to be like that with the 2 ends of the track shorted together, and it's an adjustable 0-25Ω. Replacing it with with a 100 Ω and a 47 Ω, or 2x 100 Ω would still make it 32 Ω to 50 Ω (outside this range) so I'm still confused!!! :aww: Maybe the VH4 has a different value to the Herbie? Maybe I should just go to bed, get some sleep for once and hope everything makes sense in the morning. :scared:
 
Me":2oj4pggw said:
The hum trimmer doesn't do anything?!?!? AT ALL!!! It doesn't get any better but it doesn't get any worse at all either! No matter where I turn it! :confused: Is that normal? Or is there something wrong with it? I assumed it'd get worse and I'd end up putting it back where it was, but at least I'd have peace of mind.
Click to expand...


As I said earlier my hum trimmer doesnt do anything either... I don't get it lol. Maybe it's to get rid of "excessive hum" and I deff don't have any of that....

-Alex
 
Maybe it's all perfectly fine then. Cheers for helping me sleep easier! Maybe it's a placebo hum trimmer. You fiddle with it and think everything's better like those audiophile cables that have a certain direction even though it's an AC signal!
 
Me":vdg6v64p said:
Maybe it's all perfectly fine then. Cheers for helping me sleep easier! Maybe it's a placebo hum trimmer. You fiddle with it and think everything's better like those audiophile cables that have a certain direction even though it's an AC signal!
Click to expand...


I run my cables backwards. Helps me get an original tone. :lol: :LOL: :lol: :LOL: :lol: :LOL:

On a serious note, hopefully Peter will chime in on this again.

-Alex
 
[Just as an aside, please note Alex, that the VH4 comes with this adjustment... Just sayin' :D ]
 
Ventura":33ijc4xv said:
[Just as an aside, please note Alex, that the VH4 comes with this adjustment... Just sayin' :D ]
Click to expand...


THE HERBERT HAS IT TOO MO!!!! BUT OUR'S DON'T NEED TO BE REPLACED WITH SOME RESISTORS OHHHHHHHHHHH :lol: :LOL: :lol: :LOL: :lol: :LOL:
 
Oh and Peter this isn't a complaint by any means... More of a curiosity is all.


-Alex
 
bananaladonpcp":38pboc08 said:
Oh and Peter this isn't a complaint by any means... More of a curiosity is all.
Click to expand...

+1.

That's the trouble being an engineer/scientist; I want to know everything is running at optimal performance and also how it works and why! But I guess you'd understand Peter, since it's taking apart Marshalls and trying to make sure they are running as well as they possibly can, and the intricacies of exactly what parts effect the sound that made you end up making all these beautiful amps in the first place! :D
 
The amps sounds maybe good by accident :lol: :LOL:

Anyway, thanks for the kind words :rock:
 
bananaladonpcp":3qa472li said:
Ventura":3qa472li said:
[Just as an aside, please note Alex, that the VH4 comes with this adjustment... Just sayin' :D ]
Click to expand...


THE HERBERT HAS IT TOO MO!!!! BUT OUR'S DON'T NEED TO BE REPLACED WITH SOME RESISTORS OHHHHHHHHHHH :lol: :LOL: :lol: :LOL: :lol: :LOL:
Click to expand...
:hys:

Dude, that was priceless... Literally said it out loud and then started howling at my computer screen :lol: :LOL:
 
Ventura":130inbpr said:
bananaladonpcp":130inbpr said:
Ventura":130inbpr said:
[Just as an aside, please note Alex, that the VH4 comes with this adjustment... Just sayin' :D ]
Click to expand...


THE HERBERT HAS IT TOO MO!!!! BUT OUR'S DON'T NEED TO BE REPLACED WITH SOME RESISTORS OHHHHHHHHHHH :lol: :LOL: :lol: :LOL: :lol: :LOL:
Click to expand...
:hys:

Dude, that was priceless... Literally said it out loud and then started howling at my computer screen :lol: :LOL:
Click to expand...


:hys: I hope no one ever takes us serious on this!


-Alex


seriously though the herbert is way better. FACT. :D
 
Gentlemen,

I´m a stupid guy from Germany. Please explain and
don´t let me die without wisdom. Thanks.

:cry:
 
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