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Core Concepts | '68 Fender Twin Reverb Pt 4
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- เผยแพร่เมื่อ 19 เม.ย. 2024
- A different kind of slow in-depth video.
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These are things I get asked about a lot :
Amp Tech Gear Used :
Hakko FX-951 soldering station
Weller SPG 80L soldering iron (chassis work)
Rigol DS1054Z digital oscilloscope
Thsinde 18B+ digital multimeters
Kester 60/40 solder
Techspray #4 No-Clean Desoldering Braid
Below are things that make this channel possible that people don’t usually think about. If any of these companies want to send me new and wonderful toys, I’m open to that. I can’t take free stuff when it comes to the amps I review, etc, but for the stuff below, bribe away!
Microphones/Audio Equipment :
Guitar Amps : Royer R-10 Hot Rod and/or Shure SM57 (noted in videos)
Voiceover Bench : sE Audio sE8 (small diaphragm condenser)
Voiceover Streaming : Shure SM57 with shockmount and windscreen
Voiceover Mic Arms : Elgato Wave Mic arms
Guitar Mic Stand : Gator Frameworks short weighted base stand with boom
Mic Cables and Guitar Cables : Mogami/Neutrik
Mic pre : MOTU M2
DAW : Logic Pro X on MacBook Pro 16 running Sonoma 14
Plugins : No effects other than level matching/normalization unless a recording
specifically has reverb etc added in post (rare, various Waves plugins)
Monitors : Yamaha HS7s
Monitor Stands : Gator Frameworks Desktop Clamp-On Stands
Monitor Isolation Mounts : IsoAcoustics Iso-Puck Minis
Headphones : Beyerdynamic DT 770 Pro (main)
Headphones : Sony MDR-7506 (alternate)
Video Equipment :
Camera : Sony ZVE-10 with SmallRig Cage (main)
Lens : Sigma f2.8 18-50mm (main)
Lens : Sony ZVE10 kit lens (rarely used)
B Camera : Apple iPhone 13 Pro (rarely used)
Tripod : SmallRig 71” with SmallRig Fluid Video Head
Streaming Mount : Elgato Master Mount S with SmallRig Ballhead
Bench Light : SmallRig RC 120D
Bench Light Diffusor : SmallRig Lantern Softbox
Bench C-Stands (light and overhead camera) : Neewer Pro SS Heavy Duty
Streaming Light : SmallRig RC 120B
Streaming Diffusor : SmallRig Parabolic Softbox
Streaming Light Mount : SmallRig 148CM Wall Mount Boom with Triangle Base
Various Other Lights : Neewer LED Panels with Neewer Softboxes
Video Software :
Davinci Resolve 18
Paul Leeming LUTs
Adobe Illustrator 28
Adobe Photoshop 25
Ecamm Live (streaming software)
![[Official Music Video] ฝังใจ - BOW Maylada [Prod. By Tan LIPTA]](http://i.ytimg.com/vi/rSjk1jKWRN4/mqdefault.jpg)
Masterpiece of an amplifier. Twins sound so good and "big" even at low volumes.
Alternating between long and short form videos is an excellent idea. Thank you!
Yes this!!
This amp will live well beyond most of us. Your work is impeccable Sir.
I am humbled that Lyle forgets stuff too. I bought a cheap whatever the midline squeeze action cabinet 24 inch clamp is at Harbor Fright and turned the toe piece around so the clamp is now a spreader. A couple of light squeezes after the clamp is tight enough to hold itself in place and those chassis will slide out much easier. If there are screws to loosen up, LOOSEN them up FIRST! Always a pleasure to watch such a high level of truly professional pride in workmanship from the impeccable Mr. Lyle. When I was 12 years old I blew a part of my finger off fixing Mom's Supro amp. That was 45 years ago. I have had ONE worse shock working as an industrial electrician on 4160 volts so guitar amp hazards are no joke.
One one occasion when I was working on a Marshall 50 watt plexi I forgot to discharge the mains filter caps. DOH! I had both arms on the chassis and I touched something which I should not have done. About 450 volts went in one arm, across my chest and out the other arm. It blew me backwards off of my feet and hurt like hell. I am amazed it did not stop my heart
Nice to hear about the new style cable glands. I recently had to replace one in a Vibrolux Reverb I had just bought, and the one I ordered from AES was too small for the massive 3-prong cable that was in the amp. (I did measure the cable with my "Executive Pocket Chum" caliper, and thought I ordered the correct gland). I ended up using a power drill to make the hole in the cable gland slightly larger and managed to finally get it installed. Hopefully it will never have to be removed.
I think most of us interested in amp servicing will sit through a long video, even if it contains the same info as a previous video. Sometimes repetition is good for learning. Have a banana!
Jeez so much good info in this video, thank you Lyle!
I love the detailed long format stuff!
Definitely love seeing all the work done, and sometimes the shorter videos are great too. I know the setup and editing has got to be a chore, but it's appreciated!
Hello Lyle, good cup of coffee and good content. Have a great weekend.
I still use foam to hold down the caps in the doghouse. I use the current shunt method to bias as well, and you’re right. It’s dangerous ass heck if you don’t have a secure connection. Very easy to short out 400vdc + to the chassis/tubes, or worse, YOU.
Great restoration on this fantastic amp!
Those WGS G12A’s are amazing speakers. They just cost as much as a ratty mid 70’s Twin for a pair.
I was measuring plate voltage on a Super Reverb power tube and my multimeter probe slipped so it contacted both B+ and a tube socket tab connected to ground. Half of the tab on the tube socket disappeared in a flash. Talk about a brown pants moment …
I use the output transformer resistance method to measure bias. I use the clip on style meter probes, and do the connections to the tube sockets before powering up the amp. Having 2 meters helps.
I recommend buying a bias probe for biasing, its the safest way, u just plug into the power tube sockets and plug the tubes into it, it reads in ma. And it reads both tubes to make sure your within spec.
Voltage drop/OT resistance method is slightly more accurate, and safe enough with the right probes.
Thanks again for sharing your Expertise!!!
Just finished that long format video. Watched another before that. I like to binge watch. So no, not bored.
Thank you for the post. I enjoyed the longer video. It is an opportunity for me to learn.
Ive never seen those "newer style" strain reliefs before but i think love them already lol. Im also not a fan of the older ones for a few reasons. With my own amp builds i just install an IEC socket. But for vintage radios and other older equipment that needs a new mains cable id really love to try out the newer ones. I cant say one hundred percent that ill like it better without trying it but by the looks of it and your description it seems far superior. And its perfect you get them from mouser cause thats where I try to get all my components cause i live close enough to their Mansfield warehouse to use their will call and avoid shipping costs. Thanks for mentioning it!
Lyle always good learning in any of your video's long or short. Im like a baby mesmerized by a ball when im watching your skills. I look forward to hearing the new speakers to compare with these "plain jane" Fenders.
Love the long videos cause they deep dive into an amp, especially if you can include trouble shooting. Maybe you could do the shorter ones here and there and then pick one amp to do a few long in depth videos on the whole amp so we can follow along. Some fenders, maybe next time a Marshall, Traynor etc. Love the channel!
Nice looking work as always! Thank you for the info on those power cable strain reliefs, much better version!
Great video, thanks for sharing your knowledge! I enjoy watching and learning!
I noticed that all the WGS Speakers I installed / used (and that's quite a few, including Green Berrets, Reapers (55/75Hz, HPs), ET65, G12C, Black Hawks ) required a quite long time to break in, usually +20h. Same for Jupiter Speakers which are also manufactured by WGS. This drew me off on the first pair but being to lazy to deinstall I noticed how they develop over time....
Thank you for showing that power cable clamp. I hate the old style… mostly because I do not have the special tool. That hayco(?) clamp looks like a better mousetrap.
I'm guessing you do the actual bias calculations based on the output transformer resistance and voltage drop. I'm so happy to hear that if that's true. I love you presentation style and you're calm demeanor. Thanks again for all your videos
Awesome!
Great video, thanks Lyle. I have a ‘68 JBL twin just like this, and it has a hum I just can’t get rid of. I haven’t tried the additional cap on the bias, and I wonder if that’s what’s happening on my ‘68 Bassman as well.
I leave the JBLs in my amp for originality, but I honestly prefer ceramic speakers in a twin.
love a good cliffhanger, thanks!
That is the end of the interwebs/google machine I can die a happy man.
Do what you do and we will watch. Trying to predict what people want is a downward trajectory.
Oooo. Silver MOD caps into the doghouse….
If "heat is a thing in capacitors" why would they be underneath the doghouse? Just curious, Lyle. Love your stuff, long or short form.
As caps fail (which gets more likely as they run near or at their rated max voltage) they generate heat themselves, which speeds up the failure process, which makes them run hotter…
It’s a separate issue than ambient temperature, and that is fine inside the doghouse.
Hey Lyle - do you mind to share the model number of the Heyco cable glands you use? Those original snap-ins are a pain and I’d love to try the ones you like to use. Thanks for all you do!
I'm an electrician and use those cord grips and would be made fun of all day for putting one of those on backwards, but it honestly looks less cheesy this way.
Is there a part number for the new style cable clamp? I missed it in the video if you mentioned it.
I don’t understand how AC grounds (which are super important) get stuck to the chasis with just a giant solder blob, and no mechanical joins. In all other cases the advice is to avoid tag soldering and always have mechanical support. What’s the difference?
I would guess you’d have to drill a small hole in the chasis to secure the ground a bit more.
I wouldn’t build a new amp this way, but this is how Leo built these.
What kind of silicone do you use for keeping the caps in place.
did anyone catch what size Heyco gland he was using- i never liked the old style either and am looking to upgrade-- typically use 16 awg wire -i mean he was right about to say it ...?
Lyle, first, thanks again for the great detail in the video. Because I own this same twin, I'm checking all the fine points. I've recapped mine and will look at your service carefully here.
I'm sure it's down to owner preference, but why would one not want to add a variable bias pot to the bias balance? I was thinking about doing so on mine but haven't gone that direction yet. I'm curious if you have preference or opinion on this. Thanks for sharing so much invaluable amp service information. Your viewers, myself included, are quite fortunate.
Thanks! See the various ‘70s Fender videos. In those I usually add bias level while retaining bias balance.
Was part 5 for the ‘68 twin reverb posted? Can’t find it 🤷🏾♂️
Trying to figure out how to add gain to one. I hardwired a 2008 reissue during the pandemic because I was bored and it was staring to have problems. I pulled all the pc boards. Are their any ‘gain stage’ modifications?
I tend to like 5881's ... I presume the plate voltage is too high to run those in this amp ...
How often do you find yourself moving power transformers to fit the cable glands?
Hello;
What kind of glue or silicon you use in order to stabilize filter caps onto the board? Is regular hot silicon safe to use? Thank you.
Never use hot glue in an amp. Use RTV silicone. You can get it at most auto stores.
@@PsionicAudio Thank you so much for your respond. I was about to use hot glue. I appreciate.
Anyone have a part # for the Heyco strain relief that fits Fender amp chassis please? There are lots of sizes on Mouser. The number of options is bananas!
Datasheets. Datasheets, yo.
My hole size is approx .5 x .625”, and cable diameter is .34”. I’ve looked at quite a few of the data sheets and have been struggling to find a proper match for both, which is why I came here to ask for help. You mention the SJT cable size in the video, but I see no reference to that on the data sheets. Additional guidance would be appreciated. I’m a busy guy, and sifting thru multiple data sheets is time consuming.
Zinc powder finger
Xlnt info. Long format please!
Aren’t svt and sjt two different types of wire? Wouldn’t the amperage be based upon gauge of wire?
Two different types of cable. The wire diameters are different, so the current ratings are. As are the resulting cable diameters.
Svt and sjt wire diameters are different? Aren’t they referenced by wire gauge?
Lyle how are spelling power cord clamp companies name Hakko?
Heyco
Oh no need to be sorry baby. Just traffic. But I appreciate that
Mahalo Lyle! Have a banana.
Did you get the bananas you were looking for?
Heat shrink will never not be satisfying