Supporting Vendors advertise on the tdpri

 Telecaster Guitar Forum Can someone educate me on transconductance?
 Home Forum SHOP Tele Photos Reviews Classifieds Register FAQ Search Today's Posts Mark Forums Read

 Notices

 Amp Central Station Amps, tubes, speakers & everything AMP related.

Forum Jump

 October 24th, 2008, 01:13 AM #1 (permalink) TDPRI Member     Join Date: Oct 2007 Location: Provo Age: 29 Posts: 24 Can someone educate me on transconductance? I understand something of the different tube types... I'm now trying to understand measurements taken of tubes... for example: just got a couple of 12at7's. each of these was 'measured' at 3000/3200, 3200/3200, and 3700/3900. I have no clue what this means... and I'm not sure what to Google to find the answer... can you help me?
 October 24th, 2008, 11:09 AM #2 (permalink) TDPRI Member     Join Date: Oct 2007 Location: Provo Age: 29 Posts: 24 bump
 October 24th, 2008, 03:48 PM #3 (permalink) Tele-Holic     Join Date: Feb 2008 Location: DC Posts: 657 Transconductance is the ratio of a change in voltage at the input of the tube to the change in current at the output. In basic terms, this indicates how "sensitive" the tube is to input voltage changes. A high transconductance tube swings a lot of current for a given change in input signal. Remember that a tube creates output voltage swings by varying the current through a load resistor or a transformer. You can visualize this like the voltage operates a water spigot (British term for tube= valve). Signal voltage changes are like wiggling the knob changing the water pressure. The load resistor is like a water powered generator, cranking out higher voltage as the water flow increases. A "high transconductance water valve" would create a large change in water flow for a small twist on the knob. In plain language you could say that a higher transconductance tube "amplifies" more in a given circuit. As the tube gets old and transconductance drops, it "amplifies" less.
 October 24th, 2008, 05:23 PM #4 (permalink) Tele-Afflicted   Join Date: Oct 2008 Location: USA, CA, 94585 Age: 53 Posts: 1,076 This is kind of a big question. Are you trying to make an amp run cleaner, or maybe brighter?

 Bookmarks

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Administration & Support Issues     Admin Announcements     Forum Problems & Issues     Help Threads Fundraiser Giveaway Central     Winners Circle     2013 Guitar Prizes Detailed The Deal Center     Offers, Coupons and Deals     Sweetwater.com Deal Center Main Telecaster Forum     Welcome Wagon     Telecaster Discussion Forum     Vintage Tele Discussion Forum (pre-1974)     Fender Custom Shop Tele Forum     Squier Tele Forum     Other T-Types and Partscasters     Tele-Technical     Teles on Ebay         Teles on Ebay UK         Teles on Ebay Canada         Teles on Ebay AU         Teles on Ebay DE         Teles on Ebay NL General Discussion Forum     Music to Your Ears     Today on the TDPRI     Epic Threads Amplifier Discussion Forums     Amp Central Station     Glowing Bottle Tube Amp Forum     Modeling Amps, Plugins and Apps     Amp Tech Center Vendor Forums     Vendor Forum The DIY Channel     Tele Home Depot         2013 TDPRI Tele Build Challenge     Finely Finished     The DIY Tool Shed     Shock Brother's DIY Amps     Burnt Fingers DIY Effects Owners Clubs     Guitar Owners Clubs     Amp Owners Clubs     Pedal/Effects Owners Clubs Member Clubs     US Member Clubs     International Member Clubs Other Discussion Forums     Stratocaster Discussion Forum         Strat-talk.com     Other Guitars, other instruments     Twanger Central     Just Pickups     The Stomp Box     The BASS Place     Acoustic Heaven     B-Bender Forum     Band Wagon     Tab, Tips, Theory and Technique     Recording In Progress     Worship Service Players Gig Alerts!     US Gig Alerts     International Gig Alerts And this...