Fender Bassman AC568 to AA864 Conversion + Tweed Preamp - PART ONE of THREE

This video is about a 1968 Fender Bassman (Part 1) of a series on converting the AC568 circuit to an AA864. We also change the preamp to the tweed standard. This first video shows the concepts, and integration of VintageFenderAmpRepair.com supplied circuit parts and instructions. It also includes the filter caps and power cord get replacement, and an initial general cleaning.
Here is the link for the resource described in the video.
vintagefendera...

[@pwalshj]

Lots of practical advice here. Thank you!

[@jamesbracken4618]

You do very nice work. The amps I build are cheap old pa's with not much collector value but sound very good with lots of tone, that fender clean tone is hard to beat. GOD bless you.

[@jackiekosey413]

Wow, your work is super good!

[@jamesbracken4618]

I've taken an old DuKane 1u460 pa and inserted a 65 Super normal circuit in it and it sounds wonderful, since then I've put that same circuit in 2 6v6 pa's, 1 a Bell 23 the other a Precision 20pa. all these amps cost me less than 100 dollars each off of ebay. Lots of volume. Leave the Bassman alone, original,

[@savvycircuits9683]

Sounds neat! I like your idea in making other purposed amps guitar worthy. True, the Bassman could be left alone, accept for parts that will cause the amp to fail electrically as we all know. I would like to see some of your designs if you have a way to share? Thanks!

[@michaelleonard2215]

WOW! i have a drip edge bassman that is the same circuit with the ab165 tube chart sticker as well. It is in the shop right now for power cord and electrolytics, but you have me wanting this mod pretty bad! I always wanted a little more clean headroom out of this amp and your results sounded glorious! Thank you for this awesomely detailed video! Was the tweed mod to the bass side included in the package or was that an add on you picked?

[@rickygene774]

Tweed mod was another upgrade option, and I agree, sounds amazing, for a very affordable price. If your paying someone to do these mods, be sure they don’t change the values or types of the ceramic capacitors in this circuit, especially on the normal channel. Also, depending on the tech your using, you could by these exact kits and have them installed. If your tech is a bit stuffy, sometimes they will try to get you to choose there choices, not others. Vintage Fender Amp Repair is a reputable company, and one well worth looking at when thinking of these kinds of mods. Often, when doing a heavy mod like this, techs believe that the easiest is to just replace everything. This is not always the best approach. Replacing what is only needed such as you are doing now, then taking a listen at each step is often a better approach.

[@willdenham]

I'm wondering why you would want to change an ab165. Aren't these a desireable circuit? I have a bandmaster ab165 and it roars with a Gibson.

[@willdenham]

I don't understand the title says changing from an AC568 to AA864 and the unit is an AB165 circuit.

[@rickygene774]

Hi. Sorry, that circuit is not an AB165. If you comb the schematic, and compare, you’ll see it is indeed an AC568 to begin with, before and mods where done.

[@3rdtonefromthesun]

Very in depth video but could be considerably condensed. Hell of a lot of sidetracked waffling…

[@Hillelfan02]

Is it possible to do the same thing with an ab165 circuit and convert it to the aa864?

[@jeffmaloney8701]

Yes. I’ve done it twice. Well worth it.

[@Hillelfan02]

@@jeffmaloney8701 can you please explain what I have to do or send a link to website that has the whole list of what to do? Thank you

[@Kilt_Bilt]

What Epoxy putty did you use to seat the electrolytic caps? Does it set up hard, or still remain a little pliable?

[@savvycircuits9683]

HI Brad. The putty does cure completely, retains its shape but overall is flexible after mixing. Thanks.