It is currently Tue Mar 17, 2020 2:14 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 9 posts ] 
Author Message
Post subject: Fender hot rod deville tube biasing question?
Posted: Tue Feb 23, 2010 7:24 pm
Offline
Amateur
Amateur
User avatar

Joined: Sun Oct 25, 2009 12:56 pm
Posts: 103
I just bought a 1996 usa hot rod deville or blues deville? Its missing the back plate but the circut board says fender 1996. Anyway. I need to know if this amp is self biasing or if i need it biased? i put in some tubes and it sounds killer but i did notice a small electrical burning smell? the pre amp tubes are new and arent over heating. I need this amp for the weekend and dont have time to let it sit at the repair shop. also if it isnt biased is there any chance i could destroy the amp?

_________________
Image


Top
Profile
Fender Play Winter Sale 2020
Post subject:
Posted: Wed Feb 24, 2010 11:53 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
It needs to be biased. Be careful you don't red plate the tubes.


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 2:36 pm
Offline
Hobbyist
Hobbyist
User avatar

Joined: Wed Jul 18, 2007 7:47 am
Posts: 10
Location: Illinois
Hello,
GO to this link and download the pdf's on the Blues Delux/Deville. Superb info on biasing, tube choice, etc. Hope this helps you as it has helped me a GREAT deal!!

http://www.zshare.net/download/717489209e4aa2e7/

Fender Hot Rod Deville 212 owner


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 2:52 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
Also, go to www.eurotubes.com for instructional videos on biasing.


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 4:41 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
A self bias amp need bias ajustement too

But Blues Deville is not self bias and he need bias ajustement .

This amp have no ajustement pot . You must know what you do.

And remember in a tubes amp, there are very dangerous voltage that can kill you.
Even if the power cord is diconnect from the wall .

Don' open it if your not a tech


Top
Profile
Post subject: Re: Fender hot rod deville tube biasing question?
Posted: Thu Feb 25, 2010 12:12 am
Offline
Rock Star
Rock Star
User avatar

Joined: Mon Jan 12, 2009 4:50 pm
Posts: 7998
Location: ʎɹʇunoɔ ǝsoɹ pןıʍ
gregbluesjr. wrote:
I just bought a 1996 usa hot rod deville or blues deville? Its missing the back plate but the circut board says fender 1996. Anyway. I need to know if this amp is self biasing or if i need it biased.


Even without the name plate you can tell if it's a Hot Rod or a Blues by the lack of or presence of a "More Drive" option. The Hot Rod Deville had "More Drive" and the Blues Deville did not. This is the primary difference between them. Any other difference is a subtlety. Both have solid state rectifiers.

Regardless of which amp you bought or what year or country of origin the Deville is a fixed bias amp and cannot be adjusted unless it has been modified for the purpose of installing a set of bias adjustment pots. This means if you change the tubes there is nothing to for you do with regard to bias because it is fixed. I guess theoretically you could adjust the bias by changing some of the hard values in the circuit by desoldering components and soldering in replacements but that would not be feasible or practical. I did the bias pot mod on my '96 Blues Deville 212 (Tweed). Wish I still had that amp. Very ballsy.

_________________
Image
Just think of how awesome a guitar player you could have been by now if you had only spent the last 10 years practicing instead of obsessing over pickups and roasted maple necks.


Top
Profile
Post subject:
Posted: Thu Feb 25, 2010 7:57 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
The bias still needs to be checked by a tech in a fixed bias amp. The resistor values can be changed to adjust the bias. The trimpot in nothing more than a variable resistor just like a volume pot. You can still be too hot or too cold depending on the tube manufacturer. Years ago tubes were much more robust. Today's tubes aren't even close. Get it checked, it's better than being too cold and sounding bad or too hot and smoking your tubes in a short time.


Top
Profile
Post subject:
Posted: Thu Feb 25, 2010 10:20 am
Offline
Rock Star
Rock Star
User avatar

Joined: Mon Jan 12, 2009 4:50 pm
Posts: 7998
Location: ʎɹʇunoɔ ǝsoɹ pןıʍ
Fender states if you use Groove Tubes in the Deville no bias work is necessary but you're right, if I were plugging in a set of NOS RCA BP's I would want to be sure.

_________________
Image
Just think of how awesome a guitar player you could have been by now if you had only spent the last 10 years practicing instead of obsessing over pickups and roasted maple necks.


Top
Profile
Post subject:
Posted: Thu Feb 25, 2010 11:50 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
Here's the deal, Fender owns Groove Tubes. If you cook the overpriced and over hyped GT's they don't care. It's still money in their pocket. If you are under biased in other words running too hot, you'll red plate the tubes, too cold, and it's a known fact that the HRD Deville and Deluxe amps are biased way too cold from the factory, your sound will be brittle and sterile for years. It's the icepick in the forehead syndrome.

People who say I've had my GT's for 15 years, it's because they're only biased at around 62mv or they are extremely lucky . Push them to around 85mv which according to Bob at Eurotubes suggests and the GT's will give up the ghost in a couple months if your lucky.

The downside of running your tubes hotter is they generate more heat, and many of the HRD failures are heat related like the cold solder joints on the tube sockets where they connect to the board or the 5 watt power resistors.

I love Fender amps, but not shipping and amp with it sounding it's best is silly. They just hope the folks who buy the lower end amps don't know any better and think it sounds incredible just because it's a Fender, and it's a tube amp. Not all tube amps are created equal.

Like I said, I'd pay a couple hundred bucks more for a HRDlx with tube sockets mounted to the chassis and a thick double sided PCB with plated holes like my Egnater. It broke my heart to leave the Fender amp camp after 40 years. I need reliable equipment. When my 38 year old Champ amp and 35 year old Twin outlived my new HRDlx that's a problem. That's why I'm so hard on the HRD series.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: