1965 Fender Bassman AA/AB165 Hybrid.......Schizophrenic but Sweet :)
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- เผยแพร่เมื่อ 6 ธ.ค. 2021
- This video features the rather extensive repair of a very unusual 1965 Fender Bassman with features specific to both AA-165 and AB-165 circuits, including several "unfinished" circuit characteristics. The initial issue was a completely fried 6.3VAC center-tap, but during its evaluation and repair, other unusual circuit peculiarities were discovered. Join us as we explore and repair this unique circuit.
Additional topics include alteration of the NFB circuit and use of the Polarity Switch to make it switchable, discussion of hum cancellation in 6.3VAC filament wiring, repair of my damaged Eurotubes bias probes, and modification of the Bass Channel tone stack to improve tone and favor guitar use for the customer.
If you would like to support our channel, please SUBSCRIBE and consider becoming a Patreon patron at: / uncledougsvintageamps or making a PayPal contribution to dldcam@aol.com. We receive absolutely no ad revenue from our videos and rely upon our viewers for support. Thanks for your time and consideration.
Additional NOTES: 1.) The midrange tone control idea was deemed unnecessary. 2.) The audio demo was done with single-coil pickups (as Leo intended), NFB "off", and Tone Controls at neutral (5) position. 3.) The fact that the modified 6.3VAC circuit withstood hours of circuit and audio testing justifies, IMO, retention of the original power transformer. - เพลง
Always good to see a new Uncle Doug video.
Thanks, Brad. I hope you all have a wonderful Christmas :)
Uncle Doug is a real class act.
@@kevinking2468 Thanks, Kevin :)
He and you are one of those responsible for my appetite for the "lovely hot technologies" I try to keep in my modest and insignificant channel of deliciously outdated technology.
Merry Christmas to you and a new year full of happiness.
73 DE PUSRZ - Brazil
Thank you sir.
I know you busted your ass to type this vanilla comment - thank you!
Uncle Doug will never have to wonder if he has made a positive contribution to society.
Thanks so much, Tobias :)
More outstanding content as always, Uncle Doug! When clients of my little, post-retirement, amp repair business ask how I learned to do the work, I tell them 20% from the half dozen Tube Amp Repair books I bought, and 80% from your videos. All the tube jockeys posting content out there can only fight over who's the second best. Many thanks and glad to be a Patreon supporter!
Wow, thanks so much, Scott. High praise indeed :)
I agree totally. I have seen a few other tube amp repair channels and while they were OK and largely seemed to know their stuff, they paled in comparison to Uncle Doug's outstanding explanations, attention to detail, and meticulous and well thought-out approach to troubleshooting. We've been spoiled terribly now, it's impossible to watch anyone else!
@@sharkskinboy Yep. That’s where Uncle Doug makes the difference 😉
@@sharkskinboy Thanks so much, SB and 74C. We really appreciate your kind words.
He’s made of the same quality as many of these timeless fender amps, so I think he’ll be around for quite some time!
Uncle Doug's videos are like meditation and therapy for me. These also inspire me to repair and mod my own amps and someday I plan to build one myself. Thank you Uncle Doug!!
That's great to hear, JL :)
Not only do I enjoy watching his videos while I’m awake…
But I let them run while I’m going to sleep hoping osmosis will take over.
Besides being my amsr therapy.
🤣💪👍🎸
Back in the very early 70's, I picked up a used 1965 Fender Bassman head to replace a Univox bass amp head that I bought several years earlier. It cost me $50 at the House of Guitars -- a wonderful guitar store in Western NY that I believe is still open. I paired it with a 2-12 bottom that a friend and I built with a couple of used Utah speakers. At the time I played bass in a local band. Eventually I switched to guitar, but kept the Bassman head around. Over the years, it was used by various keyboard and bass players. Once it served as an emergency replacement power head for a PA head. By the late 1980's, it was retired to a closet until my then 12 year old son decided to try playing bass in a band with some other kids. Eventually it started popping fuses and I had it serviced by a local tech who replaced a bag full of capacitors along with a few resistors. Interestingly, it still has it's original Sylvania 6L6GC tubes and RCA 7025/12AT7 tubes - except for one that was broken many years ago and was replaced by a GE branded tube I picked up at a local drug store -- remember when drug stores had tube testers and sold tubes?
Love your videos Doug, thank you!
We had a tube testing "station" just as you entered the drug store here in vancouver. Most people used it to check the tubes in their tv. New tubes were in the cabinet below the tester. Man, those were the days!
Drug store tube testers... Yeah they were a fixture everywhere. Last time I saw one was early 80s in a military surplus store, but it was still somewhat stocked with tubes.
@@telecomex Yes! The tester right near the front door with tubes stocked in the cabinet below. lol
Great deal! I remember those heads selling for $125-$150 in virtually any quantity you could want.
Yes, I do, Reggie. Thanks for sharing :)
Thanks for the cat update, we lost one to a road car run over a couple of months back. Have gained a new one (rescue from an old lady that could not look after her) - just on a year old , quite small and has either lost a bit of tail or it is just short and she cannot jump very high so its a clamber to the cat house and does not know how to scratch against the fence posts to keep her claws short. Different personality , sleeps most of the day and wakes up at 8pm to play when the kids have gone to bed - and only meows to play at 6am in the morning with a short jump onto the bed, better than an alarm clock.
She sounds like a great addition to the family, HP. Give her our regards :)
It’s my lucky day. Uncle Doug and friends are here to visit.
Break out the catnip and beer, Glenn :)
Paul Westerberg sound test sounded spot on.
Thanks for the educational upload. It’s always refreshing.
Glad you enjoyed it, Curtis :)
I found this same issue when looking into my 1967 pro reverb amp. I had to find schematics for both AA and AB, PLUS the Bassman AA and AB. I thought I was going nuts. I also had the resister to nowhere at the Bias pot. Then I couldn't figure out which way to go with it. I wanted the amp to follow the Bassman as it's so revered but then found the Bassman had the same basic schematics as the Pro Reverb. I just shelved it out of frustration but this video has given me new hope. Thanks Uncle Doug for helping us less knowledgeable to figure things out! You are a blessing.
You're welcome, Tim. Glad the video was helpful.
I do so enjoy your vids. I am a child of the 50's and went through the Maelstrom of the 60's music experience (you HAD to be there!). I played Bass (Still Do!) and then went through electronics school (USAF PMEL Lowery, Denver 1975). My take, Please keep doing what you are doing as it explains a LOT of what the teachers were trying to explain to me then😁. May you experience Good Health and Peace of Mind for a Long Time!
Thanks so much, Watcher. Likewise on the good wishes.
As usual I understand about half of this, but wow....what an episode. We missed you Uncle D.
That still sounds like a step in the right direction, PJ. Thanks !!
I ran out of superlatives to compliment your effort uncle doug. Thus I'll just say thank you.
You are quite welcome, Akram :)
Fascinating how those little caps and resistors can make all the difference. I once found a fault in a power station computer 'clock' board that turned out to be a tiny tantalum electrolytic that had been installed the wrong way around at the factory. (At the start of the shift we had just one working board, by the end, we had seven)...got me a nice promotion to boot !
Thanks for sharing with us, Dave.
I did a negative feed back mod on my 66 bandmaster years ago and forgot what I did.The drinking years..opened it today…then found this video lol….I put the feedback loop on a foot switch.I’m thinking the same as the ground switch.I’m thinking of slapping in a 500k tone pot instead and removing ground switch and death cap.Thanks for another great video Sir.
You're welcome, Mike. Good luck with your project.
my first Bassman was from a drum shop in Granite city IL... I asked him if he had any old tube amps and he said just that one! but it doesn't work! And it was a Bassman head, 1966, holding the door to his office open. I was prepared to get down and dirty and fix my first real amp, but when I got the tubes and quickly made a dim bulb tester... it came right on and I played it for ten years... that one was $35... and the panel with the fake grill was covered in gold Lamé, but I was happy it was just kind of laid on it and screwed down over the original cloth that was perfect... apparently all the bandstands and amps were required to look like that. lol
What a great find, Sean. Thanks for sharing :)
I'm just so heartened to know that other folks find this as entertaining, informative and rivetting as I do!! I am particularly interested in the NFB details :) as I already have my slope resistor switchable between 50 and 100--this is a nice option.
Thanks, Stewart :)
My dream is to build amp by myself one day. As a non-English person, I'm still learning a lot about how vintage amps are build here on this channel. Thank You Mr. Uncle Doug :)
I hope that our videos and others can provide you with the knowledge needed to achieve your dream, DM. Best of luck :)
@@UncleDoug Thank You :)
@@WRytmieBluesa You're welcome, DM.
Outstanding as usual, all the best to you and yours at this time of year.
Thanks, MH. Likewise :)
The bridge to nowhere 😁 Very nice Repair and greetings to the lovely Cats 👍🏻
Thanks, Meik :)
Uncle Doug, you trully deserve an honourary Doctorate in logical thinking, analysis, problem solving and restoration.
If only those brand new probes could be directed at the current world leaders with a good dose of common sense we would all be smiling.
Thanks so much, Alex. I agree that some serious "shock treatment" is called for with our current "leadership". Let's hope we all survive their incompetence.
I was suffering serious withdrawal symptoms Doug..! No videos from you for a month or so.. Thank God, for this fab Fender Bassman arriving to save the day. Great video, super informative with so many interesting instruction and tech tips. Thanks for posting Doug, and for reducing my anxiety...Stay safe, and have a great Xmas.. Ed..uk..😁
Glad you enjoyed it, Ed. Thanks so much. Likewise on the nice holiday wishes :)
Nothing more entertaining than seeing Uncle Doug fix whatever little red wagon is tossed his way. It’s obvious that many of those amps had parents or techs that had no idea what they were doing….Lol!…….>===>
Glad you enjoy our workshop follies, CF :)
Thanks 🙏 Uncle Doug for another marvelous presentation. In a world that a increasingly becoming a throwaway it is every so gratifying to watch some knowledgeably & skillfully work through various issue to keep vintage equipment alive & useful. Keep it coming.
Have a great Christmas 🎅 & holiday season to you & your family, yes that includes the cats 🐱 .
You are very welcome, E. Likewise on all the nice holiday wishes.
Really interesting and thorough repair video Uncle Doug! Thanks for taking so much time to explain every detail, made it easy to follow along and understand on a schematic here.
Glad you enjoyed it, Jon :)
glad your doing just as well as usual Uncle Doug : )
Thanks, CL.....you too, I hope :)
Glad to see you & the fur babies back at it! Informative and entertaining as always. Thank you for sharing with us, and happy holidays to the Uncle Doug family!
Glad you enjoyed it, NH. Likewise to you and yours.
Another great video uncle Doug..I've learned so much watching your video's, happy holidays
That's great to hear, Bob. Merry Christmas to you all.
Thanks for another great video Uncle Doug! Wishing you and your family a Merry Christmas too!
Thanks, Mike. Likewise to you and yours.
Great to see you! Looking forward to more field trips. Those you did were pretty cool!
Thanks, DD. I sold my Jeep.....and am really missing it.
This was a great again! So much detail… Thanks Uncle Doug, love watching these.
Glad you enjoyed it, K.
Wonderful work sir, thanks for posting!
Glad you enjoyed it, Nick.
Great to see you again Uncle Doug with another top notch video, thanks.
Thanks for watching, JT :)
Quite possibly the best explanation of a voltage divider I have ever seen or read. Like Brad said, always great to see another one of your videos. Wishing you and yours a very Merry Christmas and many blessings for the new year.
Thanks so much, Bert. Glad you enjoyed the video. Likewise to you and yours.
Thank you uncle Doug for the good wishes and the great video. There is always so much to learn from you. All the best to you sir!
Glad you enjoyed it, RJ. Likewise :)
An in depth repair / tune up. Thank you for taking time to share the tips and techniques. The cats seem satisfied with the level of service and have moved in
Thanks so much, Andrew. I think it's the free meals that won the cats over ;)
Thank you Uncle Doug for another great video. Your expertise and careful troubleshooting never ceases to amaze me. You sir are also extremely rare and I hope you know that! Wishing you and yours continued health and happiness, and happy holidays.
Thanks so much, BB. Likewise on the holiday good wishes.
A holiday gift for channel fans! Thanks Uncle Doug!
Thanks so much, Jennifer. Have a wonderful Christmas :)
Great tips! That one on the "vitual center tap" was very clever. Thanks for the teaching.
Hope you enjoyed it, RA :)
Yet another excellent video, Doug. Very educational, especially with small but important points like the shorting risk with the pilot light socket. Thanks again.
Glad you enjoyed it, Rodney :)
Got the new Uncle Doug video notice a little later than usual this morning so I wasn't able to watch it until after dinner. Uncle Doug and a beer is just as good as Uncle Doug and coffee. It's 13 degrees out there tonight and the cats will go out, but not without giving me a dirty look. Not my fault guys. Thanks Doug.
Hope you enjoy it when you're able, Martin. I've seen that look from my own furry pals.
@@UncleDoug I did, while having chicken fried steak and a beer.
Merry Christmas Uncle Doug and Family, Another brilliant Video, Thanks.
Thanks so much, Dave. MC to you all :)
Thanks Uncle Doug ! Your work is much appreciated.
That's good to hear, Kevin.
Thanks UD for taking us along for the ride on another wonderful video adventure as you repair yet one more piece of musical history!. I think I speak for all the viewers when I say we appreciate the sharing of your knowledge in these videos more than you know! Happy Holidays to you and yours!
You're quite welcome, Jack. Thanks for your nice comments and for joining us on this ampoholic adventure :)
Looks like Uncle Santa delivered an early Christmas present for us to enjoy. Merry Christmas to Doug, your support staff, the tubaholics and patrons.
Thanks so much, Craig. Likewise to you and all the Craigettes.
playing thru my 65 bassman right now while enjoying your show!
Sounds like a great way to play along with Ollie and Jack :)
Excellent video once again UD! Your approach to troubleshooting is indeed very helpful. Thank you!
Glad you enjoyed it, Sam :)
Thanks UD... another informative video. You are the best!!
You're welcome, Rick. Thanks !!!
Brilliant it’s good to come and watch someone with such a wealth of knowledge like yourself Uncle Doug, easily one of me new favourite channels to watch 👍🏼
Welcome aboard, Matt. Thanks so much :)
Nice to see you back!
Thanks, Rock :)
Glad to see you back on here. Missed you. Hope all is well, thanks for sharing your always informative and entertaining stuff!
Thanks, Manfred :)
Welcome back, great job.
Thanks, Paul.
uncle doug another great video merry x-mas and happy new year to you and yours.
Thanks, Big Jim. Likewise to you all.
THX UNCLE DOUG :-) HOPE YOUR DOING WELL!!
We are, Ken. You too, I hope :)
He lives! Happy to see you posting new content! Fantastic video as always!
Thanks, NGO.
Hi Uncle Doug and thank for sharing your experience. Very much enjoyed watching you work through the trouble shooting, moving from diagram to circuit.
Many blessings to you as well.
Glad you enjoyed it, DD. Likewise to you all.
Awesome video Doug. Nice work on making that amp really sing!
Thanks, Kley :)
Great work Mr Doug!
Glad you liked it, GL :)
Interesting amp issues and mod requests.
Good job as usual Doug.
Kudos to EuroTubes for taking good care of you.
Thanks, Amo. Agreed on Eurotubes......they're good people.
Nice work, Uncle Doug! Happy holidays 🍻
Thanks, WM. Likewise :)
Uncle Doug, you are the best,
Thanks so much, Cuz :)
Always a good day to see a new video from Uncle Doug. Trust you are well, sir.
Thanks, Ozzy. Never better :)
Excellent video, very thorough trouble shooting and problem solving. Thank you.
Glad you enjoyed it, Gerrick :)
Another great video put together by Doug. Thanks, you`ve mastered it.
Glad you enjoyed it, Flavio :)
That's what I love about Uncle Doug..a relentless, tenacious, troubleshooter...Always a great video and learning experience!! Thanks Uncle...Have a great Christmas and Happy New Year!!!
Thanks so much, Doc. Likewise to you and yours.
Great video. Your videos are the best tube stuff on TH-cam. I learned much watching your videos. Have a nice chrismas time, best wishes from Germany.
Thanks so much, Michael. Likewise to you and yours.
All the best Uncle Doug
Likewise, Pyro :)
Thanks for yet another very informative video! Inspired by your videos I finally built a 5F1amplifier last year, my first experience ever with tubes. It was something I wanted to do for many years and watching your videos finally gave me enough confidence to start building.
That's great to hear, Albert. Best of luck with all your future projects.
Dear Uncle Doug, great, informative video with lots of small, but great impact, modifications. Have a great Christmas season.
Glad you enjoyed it, TM. Likewise to you and yours :)
Uncle Doug you're back 💜🙏🏼
Yep :)
This was an amazing video. Well done as always.
Thanks, MC :)
I worked on a 69 Twin Reverb that was a combination of the AB763 and AA769. Was confusing at first. Transformer dates all were correct. Power transformer was from the AA769, the eyelet board from the AB763. Made it work and sounded great with a few mods similar to ones you do. I've tried the pot for variable feadback in a few lately. Works well also.
Erotubes are going to give you great service. They want the positive exposure your channel gives them. They may do it for all customers, but probably not as quickly.
Another good video! Thanks Uncle Doug!
Thanks for your knowledgeable input, KG.
Happy holidays Uncle Doug and cats. There's very few channels that give me a genuine buzz every time I see there's a new video up, basically it's just you and Michael Cthulhu. You keep making videos and I'll keep loving them, maybe one day I'll even be able to afford me some vintage fender goodness for my very own. Cheers.
Thanks, William :)
Thanks Uncle Doug. I was excited to see a new video in my notifications. My favorite parts of this video were your explanation of the virtual center tap, the way you were able to salvage the power transformer, and the noise reduction steps. This was a very practical video that I will apply to my builds.
That's good news, Rohan. I'm glad the video was helpful :)
Man that was entertaining!!!! Thank you and Merry Christmas !!!
Good to hear, James. Likewise to you and yours :)
Been watching for years, appreciate the shared knowledge and humor. Was especially interested in the virtual center tap with hum balance pot part since it pertains to an old Ampeg V2 I acquired 30 years ago and am now working on. Just a side note, I just realized today is December 7th.
Glad you enjoyed it, Andrew. Pearl Harbor Day.....lest we ever forget.
Great to get a new vid during the Christmas Holiday. Thanks Uncle Doug and seasons greetings from the UK. Rich
Glad you enjoyed it, Richard. Likewise to you all.
Aww yeah, Uncle Doug and it's a '65 Bassman? It's like an early Christmas present.
Merry Christmas, SB :)
Yet another fantastic video Doug - so informative - brilliant. All the very best to you, your family and your wonderful feline friends. Take care
Thanks, Robin. Likewise to you all :)
Uncle Doug, your content continues to both amaze me and amuse me (the latter in a GOOD way! As in entertaining and educating me.) You keep on posting, and I'll keep on watching and thumbing up!
Thanks so much, Ken :)
@BreatheScotland Not sure what this was in reference to, but my house did get a direct lightning strike (or close enough.) Took out my fiber interface (the repair fellow was in awe of the scorch marks in the interface box!) and killed one of my TVs. House-wide Ground Fault Interrupter in the Breaker box, all electronics on surge protectors, yet nature will do what nature will do.
Meh, I'm American. Bought a bigger flatscreen! :-)
But it woke both my wife and me up from a dead sleep when the bolt hit. Scary when it happened.
Very Nice Video Uncle Doug.
Thanks, Nigel :)
nice job doug very informative
Thanks, Tina :)
Another outstanding video from every amp tinkerer's favorite uncle :-)
Tried simulating the cap changes in an online tone stack calculator. The .1 uF cap makes the bass control only boost the deepest frequencies, below 80 Hz or so. Lower cap values make a wider boost and lessen the mid scoop.
Minni meows "hi" to her friends across the pond. She's bored these days as it's cold and lots of snow outside, so she can't patrol the neighborhood or hunt mice. She laid curled up beside me on the couch as I watched the video, so Minni and KC looked exactly like mirror images of each other :-)
Thanks so much, Asle. When I perform tone modifications, I rely more on my personal hearing (such as it is) than calculations. I do appreciate your further analysis of the value chosen. Holiday regards from Jack and me to you and Minni :)
Another great video Uncle Doug!
Glad you enjoyed it, Dave.
another successful job Nice playing at the end Doug
Thanks, Manny :)
That a fine amp, good to see a new video from Uncle Doug. Please have a Merry Christmas
Thanks so much, OG. Likewise to you and yours :)
Thank you Uncle Doug for great performance - as usual very exciting ! And so good, that Jack, Oli and Kacy had a contribution for all us viewers ! God bless yo.
Glad you enjoyed it, Klaus :)
thanks again for your knowledge.........best wishes in this holiday season.......stay safe
Thanks, Paul. Will do ......you, too :)
Hello Uncle Doug & Family, Good to see your hands again, great video, always educational. You do pay close attention to detail and do very nice work. I'm glad your doing well and staying busy, and, Thank you for all you do. Still working on house but getting close. I want to wish you and yours a Happy Year End, Holidays and all the best in 2022, Cass.
Thanks so much, Cass. It's always good to hear from you. Let's hope 2022 is less traumatic than 2021.....but odds are it won't be ;)
Happy Holidays Uncle Doug !!!
Likewise, Kevin :)
So great to hear your great customer service story for the euro tube product. That is very encouraging in these times when so many companies distance themselves from supporting their products. Another wonderful video and tutorial by the way, my highest compliments.
Thanks so much, Bob. I agree, Eurotubes is a class outfit. I highly recommend their products and service.
As always Uncle Doug , each video is it's own treasure chest of top shelf information , Thanks for posting . Eye's on Jack around the eggnog , he seems the indulge'r . Blessings from Florida .
Glad you enjoyed it, RJ :) Likewise from Texas.
Very intresting once again. Let me also wish you the very best for 2022!
Thanks so much, William :)
Great input! Thank you sir
Glad you liked it, Budo :)
Always makes it a good day when I see an Uncle Doug notification. I had to resist the urge to stalk you the last couple days, but I knew you would come through. :) Thanks for another very interesting amp repair. (also have a peek at my current hot rod rescue videos. not quite to your level of video yet but suffering builds character)
Thanks so much, AZ. Will do :)
As always... Great video! Thank you Uncle Doug.
Glad you liked it, RD.
So glad to see another video from my Texas pal Uncle Doug. GREAT tips too! I always look forward to these as I get older and older, and it brings a smile to my face. I'm really glad I found this channel as I continue to learn this fabulous and challenging hobby. Keep up the good work buddy and God bless you man. We're getting closer to the holiday, so I'm not sure if you'll be posting anything before then; So I wish you a Merry Christmas to your family and all those critters you have running around. I only have one big German Shepherd in the house, but we love him to death as you do yours. Oh yeah, thanks for posting about the outcome of the Eurotube's also. I have one and it's really good to see that they stand behind what they build.
Thanks for all the nice comments and good wishes, John. Have a great Christmas :)
GREAT bit of teaching! Thanx so much!!
I was wondering about 'hum balance' pots and lo and behold, you covered it...
Magic. As I write, Elvis is keeping my lap toasty and says "Hi" to your gang...
Very best of holiday stuff to you and fam, Uncle Doug
Thanks for joining us, Jonny. Regards to your furry kids :)
thanks Uncle Doug, great troubleshooting and nice to see the cats are all well. Merry Christmas from Australia!
You're welcome, Tim. I guess it's summer when you all celebrate Christmas.....it's hard for us to envision that, just as it must be hard for you all to envision our wintery, snowy Christmases. Best wishes for the holiday season :)
When I started watching an HUGE thunderstorm began so I downloaded your video so I could watch it uninterrupted by power failures or the fear of frying. Excellent diagnostics and a GREAT result. The NFB made a BIG difference on this one...sounds great. Thank you.
Glad you enjoyed it, Ray :)
Your videos are the best. Thank you.
Thanks so much, Kelli.