Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: angushung on August 09, 2010, 04:46:16 pm

Title: Looking for a reliable bias meter
Post by: angushung on August 09, 2010, 04:46:16 pm

Can anyone tell me a good bias meter that wont break my bank and can handle my 100 watt (4x EL-34b, 4x KT-88's,) heads?

Title: Re: Looking for a reliable bias meter
Post by: RicharD on August 09, 2010, 09:22:59 pm

right here

http://www.hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=TubeSockets&ORDER_ID=375667907

scroll to bottom of the page

Title: Re: Looking for a reliable bias meter
Post by: angushung on August 10, 2010, 05:35:06 am

Looks easy enough...and its in my price range. Would I need to build 2 in order to take on a 100 watt amp properly? Or would 1 tube at a time get me there?

Title: Re: Looking for a reliable bias meter
Post by: tubesornothing on August 10, 2010, 06:32:03 pm

One will get you there.  Two will be faster.  Four will be really fast.  Super duper fast if you have four meters for each of them. 

But, one is good enough.

Title: Re: Looking for a reliable bias meter
Post by: DummyLoad on August 10, 2010, 07:43:05 pm

get and build 4 then build 4-to-1 switch box - that way you don't need 4 meters. it's royal PITA to check bias on one tube then let the amp cool down to check the next, etc... not very efficient.

--ISO

Title: Re: Looking for a reliable bias meter
Post by: tubesornothing on August 10, 2010, 08:29:14 pm

Quote from: ISOTone on August 10, 2010, 07:43:05 pm

then let the amp cool down to check the next, etc... not very efficient.

Use silicone oven mitts...

Title: Re: Looking for a reliable bias meter
Post by: DummyLoad on August 10, 2010, 09:25:48 pm

Quote from: tubesornothing on August 10, 2010, 08:29:14 pm

Quote from: ISOTone on August 10, 2010, 07:43:05 pm

then let the amp cool down to check the next, etc... not very efficient.

Use silicone oven mitts...

not wise to pull tubes hot... even w/ mits.   :lipsrsealed:

Title: Re: Looking for a reliable bias meter
Post by: tubesornothing on August 11, 2010, 12:08:31 am

Quote from: ISOTone on August 10, 2010, 09:25:48 pm

Quote from: tubesornothing on August 10, 2010, 08:29:14 pm

Quote from: ISOTone on August 10, 2010, 07:43:05 pm

then let the amp cool down to check the next, etc... not very efficient.

Use silicone oven mitts...

not wise to pull tubes hot... even w/ mits.   :lipsrsealed:

bah!

Title: Re: Looking for a reliable bias meter
Post by: angushung on August 11, 2010, 05:23:18 am

I only have one decent meter. I guess I'll need to figure out what I'll need for a switch box.

Title: Re: Looking for a reliable bias meter
Post by: malt on August 11, 2010, 07:07:56 pm

Quote from: angushung on August 11, 2010, 05:23:18 am

I only have one decent meter. I guess I'll need to figure out what I'll need for a switch box.

This may help you http://www.geofex.com/FX_images/biasprob.gif but I think you have to wire the resistor to pin 8

Title: Re: Looking for a reliable bias meter
Post by: malt on August 11, 2010, 07:20:34 pm

I have some parts for a bias box but I still need some parts, got to order some from Doug.
well here is what i got so far

(http://i141.photobucket.com/albums/r63/malt_photo/solder027.jpg)