Choose Your Amp Tech Carefully

A clip from our DVD series TUBE AMPS 101 available at www.recycledsound.net

[@johnsimms3957]

I'm glad the previous repairman didn't keep the parts and tubes he took out.

[@russellesimonetta3835]

Those Pro's are great amps. A bassman circuit with tube rectifier, trem and reverb. The baby twin.

[@rjlohman]

Many thanks for posting this. I stopped halfway through the rewire, not knowing about the death cap or rewiring the fuse. I'll provide a link back on my blog documenting the restoration project.

[@jeanlawson9133]

Sir I am receiving a whizzing noise from the Audio of your Video.... thought you might like to know..... Great content 😎 and thanks....

[@wesleymorris1]

I pride myself on my work and don't do more then needs to be done.

[@donrutter6765]

Obviously a hack job. Step 1 is always replace the caps in the doghouse on a 50 year old amp with metal film resistors in the doghouse (reduces hum). Remove death cap and install 3 prong power cord. Replace all resistors on the power tubes, and replace bias capacitor/resistor. Clean pots/jacks then you are ready to bring the amp up on a variac to test voltages. Then go from there to improve the amp if need be.

[@vintagetubeamplifiers]

This is exactly how I do it.

[@wilbur1960]

I have seen my share of amatuer-tech nightmares come through my shop!!! Recently a ‘68 Deluxe Reverb fitted out with two parallel PT’s and 5881’s !!!!! Did you tidy up those nasty lead dressings as well?

[@roncarter2188]

With what you know of repair work I have an issue with a repair I just had where a guy installed a three prong cord on my tube amp. He placed the green wire not to the bottom where the transformer mounts to the chassis like I've always seen done but to a ground lug on the socket of the rectifier tube. After a few minutes of playing my guitar I reached over to get something off the table to grab something and when I touched metal I got shocked, and that ain't cool. I think it's because of where he mounted the green ground wire, what do you think?

[@rhmayer1]

Can anyone recommend a good vintage amp tech in the San Francisco bay area, preferably south bay area?

[@Tonetwisters]

Unfortunately, amp techs are few and far between in some places.

[@Tonetwisters]

Pretty sure they are the only 40-watt, 2X12 handwired amps that Fender has ever made.

[@jpphelps3663]

Are you biasing with just a multimeter?

[@recycledsound]

Joshua Phelps YES! Using the Transformer Shunt Method shown in Tube Amps 101, that's all you need!

[@jpphelps3663]

Recycled Sound thanks for the reply! Does this work with all tube amps and don't you have to install a resistor on two tube pins to do it?

[@Fletcher883]

I'm not sure how useful this comment will be given how long ago you made yours, but the each side of the output transformer primary with respect to ground in this case are resistances across which we can measure voltage drop and thus obtain the current draw. It's actually a more accurate method than placing resistors at the cathode, as the cathode measurement will include the screen current.

[@ronjinks8932]

A rectifier tube from Gt. Britain would not be the original in a Fender amp.

[@recycledsound]

Your point?

[@mobicus1]

@@recycledsound @ 3:19 you referred to it as "an original". A vintage tube? Likely, yes. Original to this amp from the factory? Likely not. I think that was the point being made.

[@ronjinks8932]

German Telefunken tubes would not be original in a Fender amp either.

[@recycledsound]

“Original” tubes are not a factor in vintage tube amps as they are like spark plugs in a car…. You must keep fresh ones for optimum performance! In this case we were simply pointing out that good, working tubes were removed/replaced by a previous tech.

[@wesleymorris1]

Hack work on a vintage amp, that's bullshit