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Messages - Jack1962

#61
Preamps and Effects / Re: Distortion
July 18, 2010, 07:13:40 AM
Sure they are , they work real well for prototyping circuits and tinkering as well, dive in and enjoy  ;D

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#62
Ohmy you can order a set of Ruby 6L6's from musicians friend probably cheaper than anywhere else ($34 a pair I think) I have them in one of my amps and have had for a few years they seem to be pretty good tubes for rebranded tubes lol lol lol
#63
Preamps and Effects / Re: Distortion
July 14, 2010, 11:08:36 AM
well it will distort your sound I will say that , the first thing I will talk about is his choice of transistors (2n2222) although they are cheap and are fairly good general purpose transistors , they pretty much suck for quality audio applications. The second thing , this guy must just have ton's of diodes , he could have stop on the first stage  with them an it would have worked fine. The Third thing is the 15 volt supply voltage , it would have been much better to design around the standard 9 volts . However the circuit will work it would be a little harsh for my taste but would work , the pots the first one is for gain and the second(last one ) is for level .  It should however be a good project , enjoy the build.

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#64
Call Yamaha Parts Department at 714-522-9958 , give the the info on your amp (serial # etc) and they will send you a diagram if they still have it .

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#65
The Newcomer's Forum / Re: Fender FM25DSP DOA
July 14, 2010, 07:47:18 AM
Enzo is right the powersupply is the place to start however, if you have hum at the headphone jack chances are you have power to the TL072 opamps , but no signal , I would puld the board , check for bad solder joints, make sure you check the input jack  fender used some really cheap input jacks on this amps. Other than that without more info it's really hard to give any valueable advise on this one.

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#66
All I can say about the design of the bias circuit is it is rock solid and allows the end user to change tubes without rebiasing the amp , which most don't know how to or aren't capable of doing , which is a great marketing tool lol . 2 thumps up on this design . AS for the operation of the vacuum tube , cathode has to be more negative charged than plate , grid introduce's a small signal to produce a large signal at the plate, if you need more info read Jack Darr's book lmao

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#67
just looked at the diagram , that's very interesting.

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#68
no doubting your word guy's , however , evertube amp I have ever worked on cathode or fixed bias , had a negitive voltage on the pin 5 the grid.

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#69
are you sure about that +15 volts on a tube grid JM
#70
Nice schematic phatt , and looks like a pretty good power stage to me.

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#71
Sorry bro (brv melvin) ANYTIME powertubes a changed any GOOD technician the bias is adjusted because the current flow is never the same in any 2 tubes , weather or it be fixed or cathode bias has nothing to do with it.


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#72
first thing you have to do is replace the screen resistors , then buy new tubes those did whayt is known as red plating , this means they are now damaged . and then you ave to rebias your amp , anytime you replace power tubes in ANY amp you have to rebias.

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#73
brother I would go with the TDA7293's , they work real well , and can produce the power that your looking for , check out the Marshall AVT

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#74
Tubes and Hybrids / Re: Peavey Mace Question ?
July 08, 2010, 12:40:29 PM
I have do disagree with Phatt , the tone tank in this amp as with most peavey's is just a variation of the FMV tone tank the most common tone tank in the indusrty, with may variations to give each amp a different flavor , I would advise you to go to http://www.schematicheaven and check out the different tone tanks and there configurations, you can greatly alter your tone thru the tone tank.

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#75
Tubes and Hybrids / Re: Peavey Mace Question ?
July 07, 2010, 09:28:12 AM
Sounds good  :tu:

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