It is currently Tue Mar 17, 2020 4:30 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next
Go to page 1, 2  Next
Author Message
Post subject: Looking for advice on a bias tester for DRRI
Posted: Sun Oct 03, 2010 8:36 am
Offline
Amateur
Amateur

Joined: Fri Mar 20, 2009 3:56 pm
Posts: 131
I'm going to re-tube my DRRI and I've been looking at different bias testers.

I think I'm gonig to go with the bias tester kit from Amp-Head (http://www.amp-head.com/product_info.php?cPath=21&products_id=33). Anyone have any experience with these?

Also, will I be fine going with just the single tester? Or do I need the dual tester (http://www.amp-head.com/product_info.php?cPath=21&products_id=31)?

Thanks.

_________________
Image


Top
Profile
Fender Play Winter Sale 2020
Post subject:
Posted: Sun Oct 03, 2010 10:25 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
This is whit I use. http://taweber.powweb.com/biasrite/br_page.htm

_________________
Life...... It's sexually transmitted and always fatal


Top
Profile
Post subject:
Posted: Sun Oct 03, 2010 11:24 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14050
Location: Province de Québec, Canada
If you don't do bias many time a week, one bias probe is enough. The pair is good to go faster.

This kit is good as the meter is.

I built a kit like this one ( a quad) but I use a Fluke meter


Top
Profile
Post subject:
Posted: Sun Oct 03, 2010 11:54 am
Offline
Amateur
Amateur

Joined: Fri Mar 20, 2009 3:56 pm
Posts: 131
stratele52 wrote:
If you don't do bias many time a week, one bias probe is enough. The pair is good to go faster.

This kit is good as the meter is.

I built a kit like this one ( a quad) but I use a Fluke meter


That's kind of what I figured. I'll only be using it to bias my DRRI once in a great while, so the single probe with the meter will probably be fine.

Thanks.

_________________
Image


Top
Profile
Post subject:
Posted: Sun Oct 03, 2010 9:11 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
djv18 wrote:
stratele52 wrote:
If you don't do bias many time a week, one bias probe is enough. The pair is good to go faster.

This kit is good as the meter is.

I built a kit like this one ( a quad) but I use a Fluke meter


That's kind of what I figured. I'll only be using it to bias my DRRI once in a great while, so the single probe with the meter will probably be fine.

Thanks.


Ok, so you get the single probe kit. Hook up one tube and let everything warm up for 15 or 20 minutes. Then set the bias. Well, now. Is the other tube balanced properly? So now you shut everything down and wait for the tubes to cool off so you can swap the probe. Hook up the other tube and wait another 15 or 20 minutes for everything to warm up again. Check the bias on the other tube. Hmmm. A little different. What was the value on the other tube? I forget. Let's swap tubes between sockets and see if they balance better. Shut down and let the amp cool to swap tubes. Start all over .......

Get the point. A lot of wasted time that the two tube probe can save you for not much more money. I use this one:

http://www.amp-head.com/product_info.ph ... ucts_id=70

You need to measure both bias current AND plate voltage. This one or the Weber is the fasted and safest way to do it. The prices are probably close by the time you add a good DVM to the cost of the Amp-Head unit.

_________________
Bill

Image


Top
Profile
Post subject:
Posted: Sun Oct 03, 2010 11:20 pm
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
Yeah djv18, Bill makes a good point. If you're going to be putting $$NOS tubes in the amp, then the plate voltage measurement is necessary. If on the otherhand, current production 6V6's, with a 500vdc plate rating, are the candidates... then the single probe-meter will be fine. IMO It really comes down to; how much information do you want, and what are you going to do with this info ? I have the Weber dual bias-rite, and it's safe and fun. But sometimes I doubt it's accuracy and end up pulling the chassis out and double checking the old fashioned way, oh well. Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 2:57 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14050
Location: Province de Québec, Canada
+1 bluesky636


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 7:31 am
Offline
Amateur
Amateur

Joined: Fri Mar 20, 2009 3:56 pm
Posts: 131
OK. A few things...

(mind you I'm a noob with amp electronics)

Is the plate voltage something that is adjustable (like the bias)? Or does it just change as you adjust the bias?

I'm going to be using Tung Sol 6V6s when I re-tube the amp. Will monitoring the plate voltage be imperative with these tubes?

_________________
Image


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 7:57 am
Offline
Hobbyist
Hobbyist

Joined: Mon Jul 05, 2010 3:50 pm
Posts: 16
Just got the dual bias probe which also measures plate voltage form amp-head.com. Works GREAT!!!!


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 10:53 am
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
djv18 wrote:
OK. A few things...

(mind you I'm a noob with amp electronics)

Is the plate voltage something that is adjustable (like the bias)? Or does it just change as you adjust the bias?

I'm going to be using Tung Sol 6V6s when I re-tube the amp. Will monitoring the plate voltage be imperative with these tubes?


Plate voltage changes inversely as plate current changes. IE.: Current increases, voltage decreases and vice versa.

It is always a good idea to check bias and plate voltage whenever changing tubes.

_________________
Bill

Image


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 10:54 am
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
dtjacob wrote:
Just got the dual bias probe which also measures plate voltage form amp-head.com. Works GREAT!!!!


Good choice.

_________________
Bill

Image


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 11:30 am
Offline
Aspiring Musician
Aspiring Musician

Joined: Fri Dec 12, 2008 5:32 pm
Posts: 329
i have one just like it works good


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 4:42 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Fri Aug 21, 2009 1:45 pm
Posts: 852
Location: SoCal323
I use the eurotubes bias probe. Works well.

_________________
Its a lifestyle.....

Image


Top
Profile
Post subject:
Posted: Mon Oct 04, 2010 11:49 pm
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
DJV18, from what I've found in the scandal sheets and reviews, the Tung Sol 6V6GT tube is dependable up to 450vdc plate volts. The DRRI has a nominal plate voltage of 391vdc, according to the Fender schematic. If the tubes are set to 30-34 mv(ma), all should be well. If you are worried, then by all means get a probe that measures the plate voltage. Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject:
Posted: Tue Oct 05, 2010 6:18 pm
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
OOPS ! I was thinking 6L6. 17-19 mv(ma) would be more like it for the 6V6. Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next
Go to page 1, 2  Next

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: