Sunday 29 June 2014

AsharpFretworks BiasPro VI....Awesome....

Awesome is the only word to describe the AsharpFretworks BiasPro VI....The black art that is amp biasing has now become easier than changing a set of strings....Again....Awesome....


The hard part of the biasing process in finding your tubes maximum power dissipation rating...."the tubes power output in watts to anybody that doesn't know"....and this is hardly top secret....practically all the online shops that sell tubes give this rating in the information about a particular tube if not in the title line of said tube....


I started off with my Evil Robot....a self biasing amp....?....over 3 days checked both the plate voltage and the cathode current with the BiasPro VI and each time got the same ratings....spot on....this told me two things....1. that the Evil Robot is rock steady and 2. that the BiasPro is also rock steady....any wavering in these ratings and something is not worth the money....


Onto the Egnater Renagade....This amp has biasing probe points on the back panel with a section in the manual on how to bias the amp yourself using any number of tubes...I had always thought that my Renagade sounded sweet....Channel 1 has 6V6's to give me a very retro tone and with a Tele gives a very passable Keef Tone and has Twang aplenty....Channel 2 has EL34's to give a very Egnater modern rock tone....tons of fun....can be a bit much....but dialed in with the 6V6's is just about a perfect do anything amp....the 6V6's taking the edge off the 80s metal tone....

"ignore the multimeter in the photos....its not needed....it's plugged into the Renegades test points"  
Using the BiasPro the 6V6's were too hot just enough to lessen their lifespan but not enough to sound too hot using the settings from the Egnater Manual....The EL34's on the other hand were well out....not hot enough....If you have read my other posts on the Renegade you'll know I have spent ages trying to find the perfect tubes for this amp and it would seem all I really needed was to bias the amp better....seems so stupidly simple now but if anybody was going to kill their amp trying to do a DIY Bias it would have been me....


Using the AsharpFretworks BiasPro VI is simplicity itself....all you need to know is your tubes power rating....then with the probes installed under the tubes in your amp the BiasPro gives you the two other values needed to bias your amp perfectly....One of the probes cables has a little box with a toggle switch on it and the switch gives you either the Plate Voltage or the Cathode Current and that's it....Different amps will have different PV's and not knowing your amps PV is going to make any bias setting a wild stab in the dark....you only need to be a little out and your risking bad tone at best and a tube letting go at worst....The CC is your amps bias setting....

Maximum Power Dissipation Rating
 JJ 6V6 S = 14watts
JJ E34L = 25watts
JJ 6L6 GC = 30watts
Tung-Sol 5881 = 23watts
TAD 6L6WGC-STR = 30watts

You then divide your amps Plate Voltage by your tubes power rating....this gives you the tubes maximum bias current....then you need to set your amp to 70% of this maximum current....

JJ E34L 25w/440 Plate Voltage = 56.8 maximum bias current
56.8 x 70 and hit the % button on a calculator gives you 39.7
39.7 being the magic number....it really is as easy as that....

"if you can not see this video in the email Blogger version....click HERE"

The BiasPro VI is designed and built in the US by Ken Koga of AsharpFretworks....they look like they are built to last....not at all like something your mate made for you....the cables that make up the probes are as good as anything I've bought over the years not cheep and flimsy looking...it comes with two probes but if you need or want 4 you can buy two more....The probes are the big eight pin versions....you can also get nine pin versions for EL84's....two more probes would have been best for my Marshalls....it will just take me longer to bias my JCM900 but I can live with that....The BiasPro will also show you how well matched your tubes are....but best of all....it works and works very well....is stupidly simple to use and for the money I think every guitarist with a tube amp needs one....My Egnater is an even better amp that I thought it was with a perfect biasing....now on to my other amps....cheers Ken your a star....this thing ROCKS....k.j.

Asharp Fretworks....
Buy from eBayUK....
Buy from eBayUS....

Sunday 15 June 2014

Tube Biasing with the AsharpFretworks BiasPro VI....

I have always sent my amps to a tech to have them retubed and biased....its not only a pain but its also expensive....But then I got my Egnater Renegade that has biasing probe points at the back and I wondered why if biasing was so easy don't all amps come with easy biasing set up points....Biasing seems very straight forward with the right know how and a multimeter and yet also a bit of a black art....


I started looking for something that would make the biasing process easy but strangely nothing is really out there....TAD "Tube Amp Doctor" make a biasing kit that only gives you one part of the equation....the Cathode Current....but you then need a multi meter to read the Plate Voltage....whats the point of the TAD kit if you have your multi meter out to read the PV you may as well read the CC while your at it....????....


Then I found this on Ebay....The BiasPro VI by AsharpFretworks....This not only gives you the PV but also at the flick of a switch the CC....all you then need to know is the Maximum Power Dissipation of your new tubes....that's easy with the internet....a bit of math....a twist of a screwdriver and your done....that all seems easy enough....

The BiasPro looks well made....all the lethal electrical power strays in the tube connecters plugged into your amp and sends Milli-Volts instead of the Volts to the Readout Module....this can only be a good thing as its these Volts that could kill you....and the reason why I don't want to mess with a multimeter in the internals of my tube amps....


"you will not see this video if you have signed up for this blogs email edition"
This video is a different kit from mine but made by the same guy....Ken Koga in Minnesota, USA


ps....I'm in the UK....the BiasPro was £73.00....Postage from the US was £14.24....and I should have paid a VAT/Duty/Handling Fee of £22.80....


....but for some reason I was never asked to pay the charge...."maybe someone at the Royal Mail reads this Blog"....gotta love the Royal Mail....So all in the BiasPro work's out at £115 here in the UK....and that's still cheaper than the TAD biasing kit that only does half the job....it was posted by Ken in the US on the 6th and I got it on the 13th here in the UK....

 I'll have a play....bias some of my amps and tell you all how good the BiasPro VI is....k.j.