Fisher X100B Treble Roll Off

[tube-a-lou]

What are you using for the small signal tubes on that?
What vendor 12AX7s and what other tubes?

Hi Don,
First two are Silvertone's from Holland
second are two Fisher's From Holland
7247's are two from England

Hope it's only tube's maybe I'll switch some around with different
Brands.

Tube

 

[tube-a-lou]

O.K. things are going from bad to worse, now the right is getting lower in volume
compared to the left, on the bright side the left sounds really nice, bright high's that's
I want in both channels. GGGRRRRR!

 

[audiodon]

Something's off.
Those Fishers are usually very consistent sounding. Are you sure of the quality of your 7247s? Did you try swapping them to see if your new problem follows a tube?
Those 12AX7s shouldn't be the problem. They're not 12AX7Bs from China, which was my concern. They tend to be rolled off and lumpy sounding.

 

[tube-a-lou]

Something's off.
Those Fishers are usually very consistent sounding. Are you sure of the quality of your 7247s? Did you try swapping them to see if your new problem follows a tube?
Those 12AX7s shouldn't be the problem. They're not 12AX7Bs from China, which was my concern. They tend to be rolled off and lumpy sounding.

Hi Don,
It's the tube's I had in there in the V7 and V2 tone Control sockets.
I started testing my tubes and started switching them and one point
the left was brighter than the right so I switched them and then the
right was brighter, with further testing I found a set to put in there that
has equal sound in both channels, wow those Fisher's are a little sensitive
to position, But will have to get a set a 7247 or 12DW7's I think those
come in Russian tube EH's I think.

Thanks
Tube

 

[audiodon]

If you're lucky, you might be able to find some EI 12DW7s. Good tubes.

 

[tube-a-lou]

Thanks Don, I'll look for those, at least now I have the problem fixed with the
high end it's the tubes.

Thanks
Tube

 

[audiodon]

Then consider yourself done. If it's good, why replace the 7247s? I was throwing it out as an example.

 

[bobbyonions]

Thanks Don, I'll look for those, at least now I have the problem fixed with the
high end it's the tubes.

Thanks
Tube

Hey tuba. Does is still sound rolled off at all to you? The fisher 400 that I spoke of earlier was restored and had good testing original telefunken's in there and still sounded rolled off to my ears. Not bad, just a matter of taste I think. I'm still trying to figure out if that is somewhat indicative of the fisher sound.

 

[audiodon]

The 500-C and 800-C and many integrateds have more on the low and high end.
That factor seems to make them very attractive to many.

I don't consider the 400 rolled off, but I've heard others that do. I tend to have long listening sessions and I'm sensitive to fatigue. When tricked out right, the 400 is the best to my ears and sounds the most like music heard in real life (not live through PA systems).
To me the others are a bit off. To each their own though.
If everybody liked it exactly the same, we wouldn't be hashing out these questions.

 

[tube-a-lou]

I do love the bass on the fisher's, there a nice sense of wallop there, and the high
end thing, I think it depends what tube you got in the amp. I'm finding that out
pretty quick now.

Tube

 

[audiodon]

The Sylvania long pinched plates are a punchy 12AX7 with plenty of extension in the preamp positions.

 

[tube-a-lou]

The Sylvania long pinched plates are a punchy 12AX7 with plenty of extension in the preamp positions.

Hi Don,
I think I might have two or three of those, I'll have to check,
Thanks for all the help.

Tube

 

[tube-a-lou]

Problem Solved to the most part, it's the coupling caps at the Phase Splitter section.
I took out the Mojo's I had in there and replaced them with a set of Illinois PWM Caps,
I'm on my way to fixing that roll off problem, it is sounding better, wow didn't think
that the caps would make that big of a difference but it did,but will try out different
type to get it right.

Tube

 

[ryanmerc]

Problem Solved to the most part, it's the coupling caps at the Phase Splitter section.
I took out the Mojo's I had in there and replaced them with a set of Illinois PWM Caps,
I'm on my way to fixing that roll off problem, it is sounding better, wow didn't think
that the caps would make that big of a difference but it did,but will try out different
type to get it right.

Tube

I know this is an old post, are these the 4 small disk capacitors in a strip near the V4&V5 tubes?

Ryan