Don't think is the jack,i have try other jack but still the same.
It's could clearly hear that some thing is wrong with the amp and the amp don't sound right.
Guess i'll try replacing the elect cap and hope it's work.
If not i have to replace the bipolar transistor or the driver transistor.
Thank for the reply

A better explanation of the problem would help.  But from the short bit you gave us, sounds like your power supply's electrolytic caps may have shorted out.  If you pop open the amp and look at them they will probably be all corroded, exploded or leaking.
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Thanks for the replay.It a old bass amp.When i plug in my bass,the sound is distorted and cracking,very obvious with the low string.
The guy who pass me the amp mention that he have not been using the amp for years.
I open up the amp and check the elect cap seen ok to me(no corroded, exploded).

How to to check for leakage for the cap?
Could it be the power amp stage that cause the problem?(it an old amp)
Thanks for any help

HI,got this bass amp from someone.The amp had this distortion and crackle sound when play..The note could still be heard but die quickly!
Need someone to direct the problem is cause by the power supply, power stage or the preamp.
Could kind soul here help me to solve the problem.Below is the schematic for the amp.

http://www.tremolo.pl/Firmowe/LANEY/RBW200.pdf

Quote from: Jack1962 on June 08, 2010, 12:49:46 PM
you may want to change the values of C3 and C8 but I would have caps there.
that 12ax7 should drive that or most any tone tank just fine.

Thanks Jack1962 for the advice. Will still build this preamp amp.It's a very simple amp for fun build.
Thanks again.

Quote from: phatt on June 08, 2010, 09:28:59 AM
Hi adamn,
              First Q/ Are you wanting clean,, inbetween rattle rock tones,,
or full on metal?

IMExperience, The valves are being wasted setup like this.
My suggestion, Google *Mesa Boogie Vtwin schematic*

It will likely run on the 60 VDC you have and it's about the best tube preamp on the planet.

I only ever built the *Clean section* and of course it should obvious that you do not need all the extra stuff.
Makes for an easy project.

If the Vtwin schematic is hard to understand I can search through my old files and find the setup I built many years back.
Good on you for having a go at something that is not easy to do. :tu:
Phil.

Thanks Phatt.I like to have the preamp in between of clean and rock.
Have search the wed for Mesa Boogie V twin.Look interesting for me.If it's possible to trouble you send me your file?
Your help is much appreciate.Thanks

Found this hybrid preamp that run on 12v dc.Was think of building this for my DIY guitar amp project.
http://www.sugardas.lt/~igoramps/grass_preamp.htm
Sound clean on the sound clip for me.Was thinking to change the tone section to marshall tone stack.
The power amp section will be LM3886.
1.Was wondering,the cap c3 &c8 still needed, if i replace the tone section to marshall tone stack?
2.Should i add a gain between the tube?

Any help?