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Re: Laney problem

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4/22/2004 10:28 PM

Re: Laney problem

point taken. However:

1. you couldn't fix it even after help from people here

2. your tech (whom I assume you paid money to) didn't cure the amp of the buzz

3. I asked you for more info and you never sent it, (and I didn't want to be pushy about it--it's your amp after all).

re: not having a filter cap: like I think I tried to explain, it a) filters and b) couples the plate current AC from plate to cathode, so I don't think it's an optional matter especially in a high gain situation like you had going. Lastly, if you knew a bigger fuse wasn't the answer why did you try it?

4/23/2004 12:05 AM

Im not trying to start crap here.Just looking for help.....geeeshhhh..!!!

Like i said,im still learning this stuff,and i really dont need what appears to be a big ego putting me down and implying i know absolutely NOTHING about tube circuits.Maybe im taking this all wrong ...???I know a little,enough to build 2 homebrews that sound very,very good.(yes,the new one still has a tiny buzz..

)

Well Dai,i sent you a layout drawing and also a schematic ,thats what you asked for....what else do you need?i must have missed something...???

As far as "the filter cap":well ,ive done a lot of Marshalls where ive added 1/2 of a 12ax7.Ive never ,ever had ANY problems or noise--and ive never added an extra filter cap. Thats what im trying to say here.I know the voltages are different in my homebrew,im still experimenting-but i dont think it needs the extra cap---just like the Marshalls i just spoke of.

ANYWAY....i guess im back to the garage to look at the Laney..

4/23/2004 12:54 AM

No need for the growing tension. Everyone is tryiing in their own way to be helpful.

km - when we might point out someone's shortcoming, it is not to feel superior, it is to suggest a direction for study. SO we point it out in public because this is a public forum. If I post something that is incorrect, I hope someone hops right on it and straightens me out. There is no saving face, what is the point. Watch how a modelling agency talks to the potential models - they don't sugar coat anything. They just say honey, your knees are too knobby or you eyes are too far apart and be done with it.

When you 1A fuse blows that means there is more than 1A of current flowing through it. The 4A fuse doesn't blow because whatever current over 1A was flowing, it was not as much as 4A. That us all we can tell from that.

The thing to do is put your ammeter across the open fuse and measure the current draw. It sounds like you have a leaky cap. When you open the choke lead, that disconnects everything after it in the circuit. So if it holds fuses with the choke out, then the trouble is further along. CHeck to make sure the choke itself is not bad. With power removed of course, measur resistance between the choke leads and the frame of the choke. It better read oopen.

If you look at the schematic, from the rectifier the high voltage goes through the choke, then through some resistors. At each point between chokes and resistors there will be a cap to ground - filter, decoupler, whatever. Any of these caps go bad, it can load down the B+ - possibly enough to blow fuses. In all likelihood, it is one of the earlier syages, since the later stages usually have a high enough droppping resistor that it won't blow the fuse even if the cap is a dead short.

Look at it from that point of view and see what you get.

4/23/2004 2:47 AM
km	I appreciate all the help--and:Enzo-----thank you very much!!!---thats exactly the reply i was hoping for-lots of things for me to check and measure---now i can really get down to business----- -------thanks again.

4/23/2004 3:19 AM
Dai Hirokawa	“Give a man a fish; you have fed him for today. Teach a man to fish; and you have fed him for a lifetime” author unknown

4/23/2004 5:43 AM
km	Thats lovely. How about another.. "Help out a fellow tube amp freak;and he will learn and respect the knowledge you have given."

4/23/2004 8:38 AM
Enzo	Stop already. How about these: "There is no I in amps." or "Amps, not attitudes." Or something. Let the rest of it drop.

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