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Bravo V2 weird problems.

post #1 of 3
Thread Starter 

Hey guys


Would like to tell you the weird problems my bravo amp has developed. It has left off for many months until I got some new headphones. I plugged it back in and all seemed normal. Until I listened to some music it sounded like crap, the sound card in my PC sounded much better then this on its own. I was using the stock 12AX7 / ECC82 it came with.


I tried using an my 12AX7 / CV4004 NOS type tube to see if this was the problem. The sound was very weak, cracked and hissed and the tube got very hot I know this tube works fine as its used in the pre-buffer of my TK2050 amp.


Another problem I nocited  was one of the LM317 was running very hot far hotter then I remember it running before. My be this its the problem? I know quite alot about the LM317 adjustable voltage regulator and have some laying around from a previous project.


I also thought it was a power supply problem. Another problem I have to pull the 5.2mm jack from the socket before I get sound in both channels. But I somehow think its the same channel and the amp has only one channel working, as it hard to see how the socket could go wrong.


Oh yeah both the tube heaters are lighting up if that helps.


Many thanks!!


ps I wanted to post this in the main bravo fourm but could not do it!!


Right I've replaced the hot running LM317 no change, although its runs much cooler now same as the other one, so that could have been part of the problem!!


However when testing, if I move the tube around inside the socket I get sound in both channels!!


It still sounds like crap but it could be a crack solder joint and bad socket. I will re-solder all the connections the on the tube socket and report back!!


Right update time!! After re-soldering the tube sockets I get perfect sound in one channel!! After moving the tube again both channels come though perfectbiggrin.gif So it looks like I need a new 12ax7 socket.


I may replace the other LM317 just so they are a matched pair.


I'm really pleased with myself I would not have dared  try and fix one of these a few months ago. Now I want to do some modsbiggrin.gif


Edited by haz101 - 6/5/11 at 5:39pm
post #2 of 3

Unfortunately the bravo units are made with very low quality parts. Even the caps are fake rubycons / the 6800uF has the guts of about a 470uF lol. When I first removed one I was trying to figure out why it was so light weight, cut it open and pulled out some tiny guts haha. Best bet is to rip out most of the on-board gear and replace it with high quality parts and then it turns into a pretty amazing little amp!

post #3 of 3

May be you should contact the seller for the problem. Their customer service is good.

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