Відео

Thank you Martin!

In a normal piece of grounded equipment, if you touch a live wire while standing on the ground, your heart will provide a path to Ground. Here’s the safety point of an Isolation Transformer with no earth: If the ground is not present for the equipment under test, so long as you only touched ONE live point on the device, your body will also be at that voltage and no current will flow through your heart. However, let’s say you’re at a gig with your unearthed amp and your mouth touched a Grounded Mic…well, you know the rest of that story.

Harley liked your tummy rub by proxy! I can think of another life-threatening way of measuring for leakage....so I won't mention that. The problem is the DMM is very high input impedance. My Fluke 87V has an Input Impedance of 10Meg! That's not going to draw out any leakage current. I know an analog multimeter has significantly less input impedance. Next time I suspect a leaking capacity, I might give it a go.

I second that request for a schematic to your LED cap leakage tool.

Didn't that amp sound sensational! It's straight guitar into amp. No pedals...and what a sound! I can't recall the settings, but why would I deny you that joy of discovery! 😉

@@PAPPIMELON I would hope the parts cobble together came from broken or rejected Guitars. 🤞

Sure thing. Put the 2 schematics side-by-side and you'll see there are not too many differences.

All Gibson 😂

Seems odd that is all they have there

They have something there but it's private hoity toity bullshit. That's Gibson these days.

@@baabaabaa-El ha. True

@@soapboxearth2 there is a whole section devoted to Chinese suppliers. Would you mind rewriting the name of the company? Is it Vlone Grand?

@theguitaramptech sorry I meant to type clone amp. It's Shenzhen Grand Technology Co. They make handwired knockoffs of marshall fender and dumble etc. I wouldn't think they'd be there at NAMM but someone on line mentioned they were there another time. I'd be interested in seeing a demonor review by a YT amp channel. They seem like something that might be a little lower end than something like Ceriatone... You also see them on mable audio web site I think. ua-cam.com/video/fwVnoQEZ0MM/v-deo.htmlsi=FySaZGGzMxtg059o

@theguitaramptech I keep commenting, and it disappears ! Lol It's shenzhen Grand Technology Co. They're just knockoffs of big brands . You see them on Dh Gate and mable audio.

I doubt they'd be there at NAMM but someone said they were there before. They're hand wired and kind of look half decent. ua-cam.com/video/fwVnoQEZ0MM/v-deo.htmlsi=FySaZGGzMxtg059o

I'd love to see a yt amp guy do a review. Maybe they'd send you one. Then again, I could see people not wanting to promote clones. Thry don't have the logos but they're cloning all the famous models. Cheers . Have fun at NAMM !!

Will do, Bob!

@@MichaelSmith-rn1qw that’s good knowledge and good respect in keeping the original parts. Well done Michael.

@@geezberry8889 yes, my thoughts too. I left it, but have serious doubts of its effectiveness.

They sure do like a "splash 'n' roll"!

I did replace the battery but the amp was collected before I could video the normal ending. From memory, I used a lithium button battery. It should be good for many years. Yep, the external battery compartment is a good idea, Mick. Two AAA lithiums would last many many years.

@ oh that’s good! My battery had done 32,years and still functioning but glad I changed it for peace of mind. I still love my JMP1 amidst all my tube and Fractal gear nowadays.

@@mickbuffalo I love hearing about the vast variety of players' tastes in sound. The JMP-1 didn't suit my taste in sound but very cool that it brings a smile to your face. For my taste, it's a Superlead or a 4-hole JMP50. Then I'm in Angus, Trower, Hendrix, Borich (Aussie) heaven.

Hi Nicolas. I don't recall the voltage, but I remember thinking it wasn't very high. Perhaps around 250-280VDC. Sorry I couldn't be more specific.

@theguitaramptech thank you

I sure will Ed. Now if you were coming as well, I could start repaying my huge debt of beers to you. 😂

Thanks Les. This will be my 4th NAMM. I love it.

It will be great to see you.

@@wsscott72 thanks for your msg. There’s a difference between him and hiss. Grounding issues rarely lead to hiss. Start pulling tubes beginning with V1 until the noise goes. Most likely a tube or resistor.

@@theguitaramptech Thanks for your reply. I've replaced all the resistors with metal films. It's a new set of tubes. I don't have extras to try, but I did swap them in the sockets with no difference. The noise is there even if nothing is plugged into the Input. I feel like it's in the Input Jacks. The No. 1 position guitar jack is wired for the No. 2 Accordion position, and the hiss is a lot less in Jacks 2 and 3. So I don't know if something is going on there.

@@wsscott72 I would not recommend shotgunning componenets on a vintage amp like yours. Yes, the input jack is a source of noise on some of those early Ampregs. Take a look and you may find that one is missing the shorting leaf, so it has no ground reference with nothing plugged in. Try grounding the tip contact with no lead plugged in. If the noise goes, try replacing the socket with a Switchcraft 12A

@@DavidMoreDotNet two VK’s!! You lucky bastard. You have a great sound…and a string back. My first thought is to see if the noise returns when you gently jiggle the tubes. If so, you have dirty sockets or a tube swap.

@@theguitaramptech Haha...THANK YOU! I spoke to my guitar tech about your video today. Well I rarely use the two VibroKings together. LIVE I use the Main VibroKing (the one that broke last week) and a Marshall. In The studio I use the main VibroKing, a 68 Super reverb, and a Marshall or a Doug Sewell head with 2 EL34s (is a copy of Eric Johnson amp). Sounds like this: ua-cam.com/video/RIgf7JgzOOg/v-deo.html The second Vibroking is a backup or if I travel more than 6 hours. I just don't want to expose the main VibroKing to he road but even so it went down last Saturday at the end of the Show. I hope is not the Reverb choke transformer. I wish you were in California. You are super good!

@ thanks David. I’ll be in California in two weeks at NAMM. I’ll wear my GAT purple top.!

@@caseykittel thanks Casey 👍

@@robbphillips2845 I take mine everywhere !

Thanks for that feedback Joe. I'll do that!

@theguitaramptech I love good coffee also

@ you are clearly a man of great distinction and intelligence, Joe.

Hahahaha! Exactly!

HAHAHA!

Hi Rob. Good work on retubing, even though preamp tubes rarely fail. Microphonic yes. Fail rare. When I hear frequencies being the issue, high on my list of suspects are capacitors and this is the danger. TAKE CARE WITH THE TECH YOU CHOOSE. Many don't know how to test capacitors, especially coupling capacitors. Seriously. They don't. If they say "I put my multimeter on the low voltage side to check for DC, ten pickup your valuable amp and RUN. The easy way out for them is to say "if one has failed, they will all fail soon". Sadly your sound passes through coupling capacitors and is they were shotgunned your amp will be returned sounding like an acceptable JCM800 reissue...not the original. Good luck.

@@theguitaramptech thank you very much, I'm definitely going to take it in 👍

Thank you. I am being crushed under the volume of repairs. I want to make more videos as soon as I can.

Thank you so much, Joe

Thank you for your astute observations and comments. Yes, in a perfect world, the amp would slowly ramp (at least within a few seconds) to its maximum voltage and not exceed the voltage on the schematics. The closest way to achieve this is by having a Variac beside your amp. Not a practical solution for anywhere but home. The large current consumer in an amp is the 5v rectifier supply. Eliminating this will extend the usable life of a Power Transformer. But you have raised some good points. I'm sorry, but I'm not sure about your speaker reference. I ordered it directly from Weber. If you suspect they are fraudulently misrepresenting their product, I recommend confronting TA Weber (Ted’s son). TA, like his Dad, are honourable men rightly proud of their product. Also, Italian Jensens are made with metric components and Weber uses imperial.

Hi Curtis. Great to have you as part of the family. You didn’t mention if your amp was a ’65 Reissue or an original from 1965. My schematic shows 415v on the plates. 124v is 8% higher than 115v. You need to also look at your heater AC voltage. It should be 6.3V AC, but I expect yours will be around 6.8V AC. We would prefer that not go above 6.9V. The power dissipation from 15mA @ 485v is spot-on. If your heater voltage is OK, you could try replacing your amazing GZ34 with a 5U4G which will drop your B+. I am so happy that you enjoy and learn from my videos. Its comments like yours make it worthwhile. Chris

@theguitaramptech The real deal! An original '65 Deluxe non-reverb. Well this video of the pro showed its voltage at 477 volts, and the schematic says ballpark 440 volts. This makes me feel better since mine settled in at 485 after 10 minutes. Thanks for the info ...a lot of ground others don't cover!