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Hoffman Amps Forum image Author Topic: Princeton 6G2 too dark  (Read 3150 times)

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Offline BobbyS

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Princeton 6G2 too dark
« on: January 13, 2023, 12:29:43 pm »
Hello,


Has been awhile since i was here last. I looked at my last post and saw it was 2013 I believe. Well, sometimes life just gets in the way. OK, I built up a Princeton 6G2 amp head, and probably my hearing has changed  :director: lol, but it sounds too dark. I would like to brighten it up some.


I built it to Fender schematic specs, no mods except the diode for the vibe. I run it into an Eminence Alessandro 12" speaker.


Any suggestions would be appreciated.

Offline SILVERGUN

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Re: Princeton 6G2 too dark
« Reply #1 on: January 13, 2023, 12:40:05 pm »
No reason I can see why it would be perceived as dark.
Try lifting the .oo5 cap attached to the tone pot. Better, worse, same, hate it?
Double check those cap values while you are there.

Offline sluckey

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Re: Princeton 6G2 too dark
« Reply #2 on: January 13, 2023, 12:54:55 pm »
Let me start by saying... my hearing is much darker than it was in 2013!    :icon_biggrin:

Try this...

1. Change the 25µF cathode bypass cap on V1 to 1µF or 4.7µF.
2. Change the two .1µF PI coupling caps to .047µF or even .022µF.

That's all I got.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline SILVERGUN

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Re: Princeton 6G2 too dark
« Reply #3 on: January 13, 2023, 01:02:38 pm »
Also, your output tubes can lose a little high end as they wear out.

Offline bmccowan

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Re: Princeton 6G2 too dark
« Reply #4 on: January 13, 2023, 05:20:11 pm »
I would agree with checking it over carefully before changing components. I built one to spec - except weber 12" speaker & adjustable bias. Plenty bright to my old ears.
Mac
“To my surprise, when I opened my eyes, I was the victim of a great compromise.”
John Prine

Offline BobbyS

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Re: Princeton 6G2 too dark
« Reply #5 on: January 13, 2023, 10:20:29 pm »
Yeah, I installed adjustable bias when I built the amp and sure am glad.

Offline BobbyS

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Re: Princeton 6G2 too dark
« Reply #6 on: January 13, 2023, 10:21:46 pm »
Thanks everyone! I am going to give these options a try!

Offline BobbyS

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Re: Princeton 6G2 too dark
« Reply #7 on: February 05, 2023, 01:24:39 am »
Thanks everyone! I changed out the coupling caps and the cathode bypass cap and it really helped. My amp has an Eminence George Alessandro speaker in it that sounded good but the amp was just too dark. The mods perked it up a bit, not a huge amount but pretty much what I wanted.

Offline tubeswell

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Re: Princeton 6G2 too dark
« Reply #8 on: February 05, 2023, 02:45:44 am »
remember that the type of guitar pups (and the guitar tone pot(s)) also affect the ‘brightness’
A bus stops at a bus station. A train stops at a train station. On my desk, I have a work station.

Offline HotBluePlates

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Re: Princeton 6G2 too dark
« Reply #9 on: February 06, 2023, 07:06:59 am »
... My amp has an Eminence George Alessandro speaker in it that sounded good but the amp was just too dark. ...

The speaker may be darker/smoother than your preference.

The Oxford speakers in the original Brownface amps were quite bright & edgy.  It certainly in in the 1962 Deluxe I have, and was brighter than a vintage Jensen ceramic or a vintage Celestion alnico speaker.

 


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