brewdude wrote:I have seen what you are describing. A sort of tone control after the OD. That would probably be my next strategy if what I was trying to describe doesn't get me where I want to be. In fact it may be a more flexible and intuitive means to managing the over bright character of the OD relative to the clean channel. However, it seems likely to be a little more involved to implement in my existing amp.
Perhaps I am confused and have misunderstood what the mod I described in the original post is intended for. I have seen this OD entrance mod coming from the channel switch to a 10M resistor to ground and a .05uF cap in series to the overdrive entrance's 220k to the 100k trim pot to the 68k grid stopper to OD1.
If I have got it wrong, what is the purpose of inserting the 10M and the .05uF combination?
What is the effective difference between using a .047uF and .0047uF cap?
Got ya!
What you are describing is the Gil Ayan OD entrance bass reduction, which is a high pass filter that dampens low frequencies and is useful, if you have a muddy OD channel that tends to fuzz out on the low strings.
brewdude wrote:
What is the effective difference between using a .047uF and .0047uF cap?
The .0047 takes more low end than the .047 uF.
Start with the high value and reduce to taste and until the mud goes away.
I ended up taking the OD entrance mod out of mine.
I was plagued with fuzzy, loose low end when the amp was turned up.
At bedroom levels it was fine and didn't show it.
Yesterday I had a brief period where I could really turn it up and the bass sounded terrible.
I use two EVM 12L's so they can handle it but it just didn't sound good.
I think it was Tony that had suggested a good cure for that a while back.
If you have a .01 on OD1 and the .005 on OD2, just flip them so the small caps is on OD1. This reduces the low end from being boosted too much in OD, then the .01 on OD2 lets the bass through but it is now tighter.
You may have to play with the value on OD1, but so far I like the .005 on mine.
OK, I looked at the photos again and I hate to say it but, Tony the #124 layout has the 250k on the Ratio (lead volume) not the Level.
That was confusing me.
It should be on the Level.
The values are correct (As per layout) Billy just labeled them wrong in his
Tony
For the sake of argument let's call V2a Drive and V2b Level for now.. Do we know for sure the 250k value DRIVE was used in all the Non HRM amps or just 124?.. if so how did the 100k ever become the staple!!.. Ceriatone seems to think so.. as well as Brown note..
" The psychics on my bench is the same as Dumble'"
Tom, I was looking at the schem and layout on the OP, so couldn't figure out what you meant when you said they were reversed. Now I understand, sorry about that!
Tom, I was looking at the schem and layout on the OP, so couldn't figure out what you meant when you said they were reversed. Now I understand, sorry about that!
Cheers,
Paul.
Paul
Thanks for pointing that out.. I need to delete all my earlier versions to keep from grabbing the wrong one.. My BAD.. :oops: .. Appologies to all and especially Tom..Layout corrected..I think I need a break..Tony
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Last edited by talbany on Tue May 25, 2010 4:55 pm, edited 1 time in total.
" The psychics on my bench is the same as Dumble'"
ChrisM wrote:Thanks Tony that layout is great now.
Did the B+4/5 issue get fixed, I forget? See my post in the files sticky if you don't know what I mean.
Chris..B+ 4 and 5 are fixed along with the PAB relay.. This was what led me to grab the wrong version when I edited it start this mess..I sent this to IC to put on the head of the page..
" The psychics on my bench is the same as Dumble'"
I thought I was going crazy because everybody was saying different things.
I thought I had the latest revision.
This one looks good, even has the relay bug fixed.
Uh oh, I spoke too soon.
This one has the mistake on the Send and Return jacks.
The brown wire should go to the Return jack.
Do we know for sure the 250k value DRIVE was used in all the Non HRM amps or just 124?.. if so how did the 100k ever become the staple!!.. Ceriatone seems to think so.. as well as Brown note..
Tony
_________________
" The psychics on my bench is the same as Dumble'"
The only non HRM I have seen with a 250K drive pot is 124.
Maybe there are others, but I have not seen them or heard of them. And I have heard of many!!!
talbany wrote:Updated!!
I suppose this question is insignificant
Do we know for sure the 250k value DRIVE was used in all the Non HRM amps or just 124?.. if so how did the 100k ever become the staple!!.. Ceriatone seems to think so.. as well as Brown note..
dogears wrote:The only non HRM I have seen with a 250K drive pot is 124.
Maybe there are others, but I have not seen them or heard of them. And I have heard of many!!!
talbany wrote:Updated!!
I suppose this question is insignificant :roll:
Do we know for sure the 250k value DRIVE was used in all the Non HRM amps or just 124?.. if so how did the 100k ever become the staple!!.. Ceriatone seems to think so.. as well as Brown note..
Tony
_________________
Thank You!!
T
" The psychics on my bench is the same as Dumble'"
