Topic: Installing bias kit and new tubes on Blues Deville...

This is kind of random but what the hell! So I ordered a new set of tubes for my '95 Fender Blues Deville and a bias installation kit since this model doesn't come with one. I don't really have any questions or anything...it all sounds pretty simple, I just thought I'd throw it out there.

The tubes have been out on this thing for quite awhile, I don't imagine they've ever been replaced, so I'm excited to have my sound not break up when it should be clean...

I'll take tons of pictures when I do the surgery.

Toodles!

"Music is the only thing that you can share with a million million people and you don't lose, you gain. It helps you to get energy and to live long, because when your soul is very happy then you don't want to die." - Ali Akbar Khan

Re: Installing bias kit and new tubes on Blues Deville...

I got all my things in the mail today and I just realized...I have NO idea what the hell I'm doing. I just know not to touch the filter resistors because it'll kill me smile So I'm gonna post something in the amp section at the Les Paul Forum and hope to get some direction...

"Music is the only thing that you can share with a million million people and you don't lose, you gain. It helps you to get energy and to live long, because when your soul is very happy then you don't want to die." - Ali Akbar Khan

Re: Installing bias kit and new tubes on Blues Deville...

I believe the way it bias's from what I've been told is with a transistor which sets a range from the power tubes, much like how the preamp tubes work.. (which I've always been happy with). I think its probably worth dropping it to a tech to have it installed amps can be lethal, a lil bit on money for a pro job is always worth it, plus they will bias the tubes too otherwise U will need to use a multimeter to set it.

Re: Installing bias kit and new tubes on Blues Deville...

I actually installed it last night, I figured out all the lethal stuff and worked it out with my neighbor. I just need to replace the resistor that I put on there because the bias kit comes with several resistors to try and the one I put on was too weak.

"Music is the only thing that you can share with a million million people and you don't lose, you gain. It helps you to get energy and to live long, because when your soul is very happy then you don't want to die." - Ali Akbar Khan

Re: Installing bias kit and new tubes on Blues Deville...

I posted this on the Gear Page and Les Paul Forums as well but I thought I might put it here in case anyone can help me out...

I'm sitting down and revisiting some stuff that wasn't going quite right when I went through this the first time...

So I did the mod, which was pretty clever actually. They have you install a 1 ohm resistor onto pin 8 of the left-most power tube, so the resistor is the connection between the tube socket and circuit board. Then you connect a wire to the lead of the resistor/pin near the tube socket, and you solder a bias monitor test probe jack to the end of that wire. Then you clip the existing bias supply (resistor R87), and attach a wire to the top lead, which goes to a 10k bias pot.

You have to play around with the resistors that you have on the bias pot since they're made for different ranges, but the problem is I'm not getting a correct reading when I connect to the test probe jack and the chasis.

I should be getting somewhere between 28 to 35 millivolts and I'm only getting about 1.

The amp actually works, it just distorts even sooner than it was before. I tried biasing by ear by just replacing the first resistor on the bias pot with the highest value I had, and it didn't make the amp any less hot.

The more I think about it the less it seems any one out there would be able to help me from this description alone, but I appreciate anything I can get.

Ah and here's an interesting bit of information, it may be something wrong with my Blues Deville or maybe it's just the design but the filter caps are nowhere near lethal when the amp is turned off. It's less than 10 V for each one. They charge up a little when the amp is turned on, but they don't become dangerous until you go off of standby. Once you do the supposedly 350 V filter caps jump to only around 235 V, which I know will still kill you, but it's just less than 100 V less than what it should be for some reason. The two 500V caps are running at 420V and 380V respectively. I don't really need to know why these caps are running at less than they're supposed to, but if anyone knows I wouldn't object to hearing.

Looking forward to some replies...I learned a LOT with this little experiment.

"Music is the only thing that you can share with a million million people and you don't lose, you gain. It helps you to get energy and to live long, because when your soul is very happy then you don't want to die." - Ali Akbar Khan