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The world famous "Torres EZ Mod" for the ultra-linear "junk" NOT! Fenders.

DOWNLOAD "Torres EZ Mod" for ultra linear Fenders

The 70 Watt and 135 Watt Fender Combo amps from the late 70's, early 80's are actually some of the best amplifiers ever made.

Their ultra-linear output transformers are a mystery to many people, and stupidly labeled as "junk" or bad. Ultra-Linear is a design that puts the power tubes much closer to Class A, while also providing much more power.  It is state-of-the-art tube amp design and Fender should not be faulted for trying so hard.

the reason the amps have an unsatisfactory tone is the CBS era changes in the PREAMP.  A correct redesign of it will produce a "more blackface sounding" amp but it will still "suffer" from more power, more bass, cleaner midrange, much better high frequencies etc.

Change the midrange pot to a 25k and be sure to rebuild the phase inverter completely - everyone world wide has been amazed by this "Torres Mod" of the ultra linear Fenders.

Once the amp is biased correctly it really shines with huge tone, lots of frequency response and fantastic performance.

this mod is a pictorial layout of how to convert the bias balance pot to an adjustable bias.

It will work on all the amps including the Bassman 70 and Bassman 135. It is  Pretty easy, just takes a few minutes and really amazing results.

Note: these amps do not have rectifier tubes (they can't very easily with the duplex power supply) and are rated for either 70 watts or 135 watts. Non-Channel switching combos and heads.

I have built a few dozen with the power supply down on the floor of the cabinet with the 4 rectifier tubes it needs, and with a power supply that is actually adaquate to put the amp in pure Class A with 4 x KT88 tubes and 120W of Class A power.  A gigantic Deluxe Reverb (although Deluxe Reverbs are NOT Class A, this amp design is WARMER)   Also a tube voltage regulator for the preamp, and DC filaments throughout for super low noise.  THEN it is the most fantastic silverface find there is.   this is not included in the Download.

Your download will appear as a DOWNLOAD button on the order confirmation page. You can also get to it, even from another computer from the ORDER STATUS PAGE. if you have trouble, please contact us with your order # and we will send you a copy

DOWNLOAD How to convert the 70W and 135W Fenders to adjustable bias
DO7605 DOWNLOAD$2.95
final notes on web page

Dan's Legendary Book "Inside Tube Amps" is now available on Amazon/Kindle

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Torres Engineering

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Yuba City CA 95993

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I am Partially retired due to illness, but getting better!

in business 48 years