Some whats the consensus on adding lets say a .22 uf and a .022 uf caps in the power supply.
Add them on the main filter only?, on the last preamp filter?, or both the first and last filter?
Seems some in the HI Fi crowd use a .68uf and a .01uf.
Filter bypass
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Stevem
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Filter bypass
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Filter bypass
I usually put a .022uf on the first preamp filter node. That, along with UF diodes helps create a very clear sounding amp (provided everything else is done right).
I don't put the caps on all the nodes--it gets too hi fi sounding.
I don't put the caps on all the nodes--it gets too hi fi sounding.
What?
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gui_tarzan
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Re: Filter bypass
Where are you putting these? Can you show me a diagram? I'm still very green when it comes to the design & theory part of amps.
--Jim
"He's like a new set of strings, he just needs to be stretched a bit."
"He's like a new set of strings, he just needs to be stretched a bit."
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Stevem
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Re: Filter bypass
Across a power supply filter so the chosen cap(s) your adding must be rated for at least the dc voltage seen across the filter you are adding it to.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Filter bypass
That would be in parallel to the filter electrolytic.
My brother got me to build him a hi-fi tube amp that I am just finishing - the PS is PITA
[img:500:500]https://farm8.staticflickr.com/7003/13361139645_4b3b5729f8.jpg[/img]
My brother got me to build him a hi-fi tube amp that I am just finishing - the PS is PITA
[img:500:500]https://farm8.staticflickr.com/7003/13361139645_4b3b5729f8.jpg[/img]
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gui_tarzan
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Re: Filter bypass
Yeah, that's a lot more complex than my Fender filter cap boards. Is the smaller one at the top in the middle the one you're talking about? I was hoping more for a drawing, it's impossible to see where that's connected in that pic. That is a lot of filtering. And are you talking about using the UF diodes at the PT secondary or somewhere else?
--Jim
"He's like a new set of strings, he just needs to be stretched a bit."
"He's like a new set of strings, he just needs to be stretched a bit."
Re: Filter bypass
See the schematic here:
http://diyaudioprojects.com/Tubes/EL84- ... matics.png
The 0.1uF film caps are wired in parallel to the 100uF electrolytics (little black caps protruding between the F&T electrolytics on the picture).
http://diyaudioprojects.com/Tubes/EL84- ... matics.png
The 0.1uF film caps are wired in parallel to the 100uF electrolytics (little black caps protruding between the F&T electrolytics on the picture).
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Gibsonman63
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Re: Filter bypass
I'll show my ignorance as well. What are we trying to accomplish with the smaller bypass cap?
Re: Filter bypass
The Hifi builders do this. IIRC it's a 1000 (100?) to 1 ratio, something about them resonating if the bypass is too big. If you google this you will get a ton of DIY hifi talk about it - mostly very positive but it's a different universe. I've avoided it as the guitar guys talk bad about it, but it never occurred to me to try just one stage and the pre at that. Thanks for bringing that up. It's so easy to do I think next time I break open an amp I'll try it.
Might be a good way to find a little extra brightness in a dark amp w/o messing with a good tone circuit. Hmm, maybe I'll crack open my 5F1.
BTW people stack the bypasses too i.e.: 100 - .1 - .01 - .001, seems nutty. They bypass the cathode bypass caps too. Hmm, 5F1 again? Anyone try this? Does it skew the tone weird?
Might be a good way to find a little extra brightness in a dark amp w/o messing with a good tone circuit. Hmm, maybe I'll crack open my 5F1.
BTW people stack the bypasses too i.e.: 100 - .1 - .01 - .001, seems nutty. They bypass the cathode bypass caps too. Hmm, 5F1 again? Anyone try this? Does it skew the tone weird?
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gui_tarzan
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Re: Filter bypass
Ok, now it makes sense. It seems redundant but I guess if it works...
--Jim
"He's like a new set of strings, he just needs to be stretched a bit."
"He's like a new set of strings, he just needs to be stretched a bit."
Re: Filter bypass
This probably won't make a dark amp brighter. It is more about clarity. If it is a dark amp, it will be just a little bit clearer dark amp--if that makes sense. Put another way, it's not like adding a treble peaking cap across a resistor or adding a bright cap to a pot--it is just a clearer sound. From my experience, the overall frequency character of the amp doesn't change.
What?
Re: Filter bypass
So Jana
You're talking about "noise" cleaner not distortion vs clean sound, right?
So if your amp is dark or bright this will not clean that up but make the tone you already have clearer. Interesting....
Thanks...
You're talking about "noise" cleaner not distortion vs clean sound, right?
So if your amp is dark or bright this will not clean that up but make the tone you already have clearer. Interesting....
Thanks...
In theory, theory is the same as practice. In practice it's different.
Re: Filter bypass
Right, and part of the spiel of hot shit super caps like Black Gates was that they were so low ESR and so good they could go un-bypassed.Jana wrote:It's not redundant. It has to do with the ESR of caps.