High end shrill on the 101B...

Nev

New member
So I've had my 101B for a few months now. I've read that it's going to take some time to dial it in and to tweak the tone knobs by your ears and not your eyes. So I set the knobs to what I prefer, play it for a while. Then shut it down and return another day to see how those settings are to fresh ears.
I have read many times that the 101B is a "Darker" sounding amp than say a Marshall JCM 800 (Which I have), but I've noticed a piercing high end frequency coming out of the amp when I'm on the Red channel and playing on the high strings. I adjust the Presence, Treble and Mids to fix it. But that affects the overall tone that I was trying to keep. Just when I think I've got it tuned in good for rhythm riffs, I go to do some solos, and the piercing frequency is there.
I adjust the Presence for that channel which I have dedicated to Red, but it get's that "Blanket over your speakers" tone when you lower it too much.
Blue channel is acceptable, it's a bit Bass heavy, but not bad and not as harsh on the high end.
This doesn't happen on my Marshall JCM 2204 or my JMP 2204 got those tuned in real good.
Is it the amp? If so, how do you fix it?
Could it be the V30's in the Slanted Bogner cab?
 
Last edited:

Ventura

Well-known member
So I've had my 101B for a few months now. I've read that it's going to take some time to dial it in and to tweak the tone knobs by your ears and not your eyes. So I set the knobs to what I prefer, play it for a while. Then shut it down and return another day to see how those settings are to fresh ears.
I have read many times that the 101B is a "Darker" sounding amp than say a Marshall JCM 800 (Which I have), but I've noticed a piercing high end frequency coming out of the amp when I'm on the Red channel and playing on the high strings. I adjust the Presence, Treble and Mids to fix it. But that affects the overall tone that I was trying to keep. Just when I think I've got it tuned in good for rhythm riffs, I go to do some solos, and the piercing frequency is there.
I adjust the Presence for that channel which I have dedicated to Red, but it get's that "Blanket over your speakers" tone when you lower it too much.
Blue channel is acceptable, it's a bit Bass heavy, but not bad and not as harsh on the high end.
This doesn't happen on my Marshall JCM 2204 or my JMP 2204 got those tuned in real good.
Is it the amp? If so, how do you fix it?
Could it be the V30's in the Slanted Bogner cab?
Try putting a fresh 12AX7 into V1 and going from there??

Didja buy the head new??

Might need a re-bias or some new preamp glass across the board. Do you have any noise coming from your electrical path?? Red channel can sometimes run with this hum/buzzing and really piss one off - been there. Clean power - helps.

Keep us posted.
 

glpg80

Well-known member
I play my bogner 101B through greenbacks and don't have that same shrill attitude you speak of on solo notes. Here's a youtube video for comparison, see for yourself. I think you need to roll preamp tubes, verify bias is correct/not drifted, and possibly look into using different speakers.

 

Nev

New member
Switching cabs to Blackbacks definitely helped. Swapped V1 tube didn't do that much. I'll need to look up how to do Bias.
I'll keep tinkering thanks guys.
 

sixpakldp

New member
Check the preamp tubes for microphonics. Sometimes you can hear a “ping” when playing when that happens as well as some unusual feedback or noise.
To do that, take the back panel off, set the amp to playing volume and use one of the gain channels.
Gently tap each preamp tube with your finger. If it sounds like someone tapping a microphone then it’s microphonic and replace it.
Also if your amp is post ‘04, then the red channel has an extra bypass cap to increase the gain. My amp has the marvel mod which allows pre ‘04 (lowest gain), post ‘04 and the Cameron mod. I don’t really care for the post ‘04 sound at all. The pre 04 I like because the red channel sounds more like an extension of the blue.
If you want to try that, without the mod there is one cap you need to desolder and you are pre ‘04.
 

Rdodson

Well-known member
I play my bogner 101B through greenbacks and don't have that same shrill attitude you speak of on solo notes. Here's a youtube video for comparison, see for yourself. I think you need to roll preamp tubes, verify bias is correct/not drifted, and possibly look into using different speakers.

Oh heck yeah! That IS the Bogner higher gain sound!
 
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