Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Tyrannocaster on July 24, 2012, 12:54:24 pm
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I'm just about done with this FrankenPro and there is still one hole in the face for a pot that's going begging. It's right next to the line out and it occurred to me that because a straight padded OT signal is really bright and buzzy without some treatment maybe I could put a tone control on it for live use where EQ options are sometimes limited, or perhaps there are better ideas. I've attached the line out circuit that I used.
I'm used to tone controls on 500k and 1 meg pots - are the cap values different for this smaller guy? Is there something that would provide a better "speaker" EQ than a simple treble cut without requiring more resources? There's really no board space free nearby so it would have to be pot mounted, which is why I thought a plain old tone control would be the most feasible choice, even if it isn't all that effective. Better than nothing, that's all. And it would plug that hole. :icon_biggrin:
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If it were me, in that empty spot I'd install a Talent Boost switch.
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Oooooooooooh, Talent boost switch, I need to get me one of those. :sad2:
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I figure if I can't find something useful to put there I'll cover the space with a plate that says FUGLY in Brush Script. Well, there goes this thread, LOL.
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Well to your actual question, I've never heard of that, but then I've not heard of many things (just don't get out much). You could put a pot in there, and whenever someone says "hey, what's that?" you can yell "Don't touch that, holy smokes don't touch that!". :laugh:
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Or put in a lighted switch that does nothing more than glow some interesting color when you flip it. Ask people to experiment with it, and wait for them to talk about the subtle ways it changes the tone. :laugh:
But seriously, you could implement something like the Moonlight tone control (http://amps.zugster.net/articles/tone-stacks/#Moonlight), but you would have to scale the values to work with your line out level pot. Aiken has a good article on tone control scaling (http://www.aikenamps.com/ToneControlScaling.html).
Or just find a way to monitor your line out (plugged into a recording interface or something), install whatever tone pot you want to use, and then connect a capacitor decade box and try a bunch of values until you get the sweep that sounds good to your ears.
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Or put in a lighted switch that does nothing more than glow some interesting color when you flip it. Ask people to experiment with it, and wait for them to talk about the subtle ways it changes the tone. :laugh:
Yes, If you really want to test the placebo effect tell them it slighty increases treble, or tell them what it "does". I'm sure you'll get "Yeah, It's not much but it is a little brighter when I flip it". It's amazing how the eyes affect the ears.
I'm for adjusting the tone on whatever the line out is plugged into rather than a tone on the line out.
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I'm sure you'll get "Yeah, It's not much but it is a little brighter when I flip it". It's amazing how the eyes affect the ears.
Technically, I guess if it lights up then it is a bright switch. :icon_biggrin:
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Har, har. :laugh:
Well, I put in a 50k pot with a .047 cap to ground after some trial and error. It acts like your basic Strat tone control and rolls off some of the line out's highs noticeably but seems to have no effect when all the way up. So at least the knob does something. Now I have to figure out another place for the FUGLY sign.
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Hi Tyranno. Most of my builds have passive FX loops and i have the jacks on the front panel, so if another hole can be drilled stacked or side by side might do the trick. :icon_biggrin:
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I'd make the line level adjustable, so you can run it into any gear you choose. I'd think a tone control would only make a bad line out sound worse.
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If you look at the schematic you'll see that it is adjustable. And yes, most of the time you would be right - a treble cut would make it sound worse...unless you were running it into something odd (and I have had this happen) where you don't get any control over it at all and the result is basically flat - that sounds pretty bad compared to the speaker, which has much, much less high and low end and (of course) pronounced peaks in the middle. I have no idea how to try to emulate that so I settled for the adjustable high cut along with the adjustable line level which, incidentally, is hot enough to drive anything in the known universe. That's why it's adjustable.
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If it were me, in that empty spot I'd install a Talent Boost switch.
When I helped some firends build a home studio, we installed jacks and volume controls for headphones on the wall in each room/iso booth.
Just for fun, we placed a pot and knob connected to nothing labeled "Suck". After a take, we might use the talk-back system to tell the player to, "turn down the Suck knob."
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"turn down the Suck knob." Some nights are like that! :laugh:
I use FastFret or something like it. I call it Talent Grease.
I think it's past it's expiration date or something, though.
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I think it's past it's expiration date or something, though.
:laugh:
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If you look at the schematic you'll see that it is adjustable. And yes, most of the time you would be right - a treble cut would make it sound worse...unless you were running it into something odd (and I have had this happen) where you don't get any control over it at all and the result is basically flat - that sounds pretty bad compared to the speaker, which has much, much less high and low end and (of course) pronounced peaks in the middle. I have no idea how to try to emulate that so I settled for the adjustable high cut along with the adjustable line level which, incidentally, is hot enough to drive anything in the known universe. That's why it's adjustable.
Oops, sorry I missed that! Yeah, I've tried simple R/C circuits that try to emulate speakers, but the result in my opinion sounds worse than the one in your schem.
If you're not getting much use of the tone control, the back panel is always a nice spot for variable feedback or resonance type control as it's close to the speaker jacks.
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Another good use of the hole would a be a switch labeled "carbon comp" in one position and "metal film" in the other.
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When you posted your question I was thinking about where I've seen something similar to what you are asking for
now I've remembered which was the schematic, but it isn't exactly what you want
here you can see a dummy load with incorporated tone correction circuit
http://www.tube-town.net/diy/tt-pos/tt-posx-en.html (http://www.tube-town.net/diy/tt-pos/tt-posx-en.html)
about the use of the hole why don't put a dummy load circuit like in the Koch Twintone
(see Half-Power Option/25 Watts on the manual) so you can halve the output power
if you do that by a switch instead by the jack build in switch you will have your faceplate hole busy
K
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Hey, thanks for that. Unfortunately, I don't have any chokes lying around right now or I'd try it right away. But I'm filing the diagram for future reference; I'm gonna need that. I'll bet it does a better job than the simple treble cut I used.