D-lab series Basic Training Tube Guitar amp repair Fender mini Tweed 5F1 Kit No Output ask Fred
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- Опубліковано 24 бер 2023
- D-Lab electronics basic training. This time we troubleshoot a Fender type 5F1 design made by a kit company. After completing the build, the amp would not produce audio. This is a common problem which can be caused by many things. Normally, its due to poor or missing grounds. The grounding scheme in this kit is not a good design. They utilize 2-3 terminal TB's held in place by the transformers mounting bolts. The TB's base hole is too small for the transformer screw size, so they have you clip the base and shove it under the transformer mount nut. Then of course these TB's are out of sight, so working on them is next to impossible. I elect to abandon them and install 1 accessible ground + filament resistor TB. It really cleans up wire routing. Yes, I do solder the TB ground tab, but you can accomplish the same thing with a #6 screw and dual lock washers. Diagram of the new wire routing/ground distribution is shown in the video. If you'd like a copy, e-mail me. Other build errors were discovered but not covered in this video.
- Наука та технологія
After building many tube guitar amps, kit or from scratch, yes grounds can get you. My problem wasn't missing signal, but extra buzzy noise. The PT center tap and filter cap #1 were grounded in different locations causing current flow between the two, which caused noise to be introduced elsewhere. I solved this after reading some materials on how grounding works, and hum loops are created, by putting them on a common ground lug, and doing like you did, soldering the mechanical connection for a lower resistance to the chassis. I was very relieved to find the fix so simple. I have not forgotten that simple lesson, and all my tube amps since have been fairly quiet. I like that you are showing people the basics of using a continuity test on each ground segment. Simple and effective. Which is why I like working on old tube amp designs.
I sure hope your having as much fun as you appear to be having.
..and that type of grounding problem also is the cause of a lot of Electric instruments going on the fritz too. Thanks for the Training, it all comes in handy one day!
I've got a can of that solder paste from the 1980's. lol. Thanks Terry for another great training video.
Just finished one of these yesterday. Everything works, get low hum but...no output. All grounds tested good. Visual inspection revealed the Eyelet 10 to Jack 2 wire was caught underneath the mounting bolt/locknut and shorting the input signal from both jacks to chassis ground. Works great now.
Snozeramous always gets two thumbs up from me. 👍👍 Another quality D-Lab troubleshooting video!
For a second there I thought you where just going to solder the tab, glad you put the pop rivet in there, otherwise you could do a kobbler vid on your own work 😂
Nice lesson! Thanks D-Lab.
Great video thank you for sharing your information more new Fred videos please
I remember the TV fixit man coming to our house with a box like that ... back in the old TUBE TV days.
Hey Terry, Great vid, shows you how the grounds can let ya down..! if everyone would just take a little more time to recheck their builds, this might not happen..Top job as usual..Ed..uk..😀
Thanks D-Lab. Practical and informative. Always a winning combination.
Snozeramous is amazing 😊 quick and very helpfull Video Terry 👍
Great "basics" ! Enjoyed watching, thanks for your time.
Great vid......thank you for using the KISS method once again. Great Job!
Well Done!
Great video Terry,very well explained.
The actual info you have included here is really instructive. Thanks, actual info portion guy. (-:
Thanks!
Allwais good job Terry. Tank you frend.
Nice video sir thanks
Thank you again for a great tutorial!
ONLY Terry can!!!!!! Thanks buddie
Using that looper pedal as a guitar audio source is really a great idea, Terry. Who thought of that?
Terry, another "classic" basic training.. You have not lost your entertainment skills - but that's my opinion LOL😁
Thanks man, I try to keep it interesting. Getting older, yes loosing some of the craziness.
Thank you, sir! Great video.
👍👍
Thanks! D-Lab🐭
The only way to fix a ground, is to pour more dirt on it ... heh-heh .... (My older brother used to say, "The only way to fix a short, is to make it longer!") Goes right along with "Porchaghool"! Hunh?
Ha.....done that very thing in the past.
Great stuff Terry. The only other thing bugging me about the build are all the little wire ends that need trimming
Much more tidy up work has been performed. The video focused on grounding
@@d-labelectronics 😅
I have a question Doug, how do you bend the .010 brass plates and how would you ground it to an aluminum chassis. I would like to clean up some hum in an amplifier
What is so special about Burnley Soldering Paste compared to other soldering pastes?
I want a D-Lab golf shirt
Really enjoying these tube amp training videos..picked up many "tricks of the trade" following your great and varied content. Thank you for what you do! .. BTW, what software/CAD program did you use to create that neat wiring diagram with your modifications shown at 6:20 in the vid.?
I use Microsoft Visio
Thank you D-Lab. I built a similar kit, successfully but lack the theory understanding of moving the volume pot ground to the preamp ground. I was curious about the Kalamazoo Model 2 choice of 47uf and 22uf’s filter capacitors. I also have a Model 2 but kept the filter caps with 20uf, and 10uf’s. I’ve read on a different forum about grounding the 20uf separate from the 10uf’s but haven’t made that mod yet. Great videos! -Dan.
Separating the grounds of the preamp stage caps from the power stage caps will sometimes reduce hum in the amplified audio signal, hopefully resulting in an amp with a lower signal to noise ratio. It can do this by reducing current ripple from the power supply from getting to your preamp stage. If your amp has good signal to noise characteristics, ie, nearly imperceptible hum to the ear, don't bother with the mod. I've had an amp that I grounded poorly, hummed like crazy. I totally reworked the grounds on that, the problem was in the power stage grounding, and it paid off. If it sounds good, its good. However, there are various means to grounding and some are inherently better than others, the theory of all that is beyond my ability explain. Aiken Amps web page has several pages dedicated to explaining grounding in tube amps, I found it a good resource.
@@patchesthejaybird8431 Thank you Patches. I’ll check out the Aiken Amp page. My Model 2 amp has still a little hum, but greatly reduced when I replaced the filter caps. Still, I wonder if that’s why Terry went to 47uf and 22uf caps, although he kept their grounds together. -Dan
Jeje