Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kwm488 on May 20, 2011, 06:35:15 am
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Hi
my friend pay $2500usd to buy this fender custom shop vibroking amp 5 year ago. it highlight this is a handwire point to point amp. in that time, i don't know electronic of guitar amp. and i think point to point is sound better. in that time, this amp sound very good. but after i mod my fender bassman and buy a vintage twin reverb. i think this virboking sound not good, because fender also use rubbish parts to this amp also, just pay more money to fender point to point. and PTP don't affact sound.
now, my friend amp have some little problem, so i try to help him fix it.
i have one question, this amp have 1 1n4007 which mount in the powertube socket pin 3 and pin 1, pin 1 is go to ground. what purpose of this in4007? and i add the 1ohm resistor from pin 1 and 8 to ground for bias tuning. but even i turn the bias pot from 0 to max, the ma from the pin 1 and 8 to ground is also 0. why?
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3541.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3544.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3545.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3547.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3548.jpg)
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this amp have 1 1n4007 which mount in the powertube socket pin 3 and pin 1, pin 1 is go to ground. what purpose of this in4007?
It's a protection diode. It should be rated for about 3KV. IT SHOULD NOT BE A 1N4007!
Read this web page... http://www.tubedepot.com/d-r3000.html
and i add the 1ohm resistor from pin 1 and 8 to ground for bias tuning. but even i turn the bias pot from 0 to max, the ma from the pin 1 and 8 to ground is also 0. why?
Maybe you forgot to remove the ground wire from pins 1 and 8? Maybe your meter is not set to the correct scale to measure millivolts.
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Nice pics
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I don't have a problem with the parts Fender used.
I used to own a Fender Tone Master amp, and on one point, the amps are similar. Neither of them sound exactly like an old Fender amp. They are optimized to sound great at stage volume with a band, not quieter playing with a single guitar. On their own, you might feel the amps sound stiff and bright. When I played the Tone Master on stage, I had guitar players coming up to me during breaks between sets to say how great my amp sounded.
That said, I play at home alone more than I do onstage, and neither of those amps sounded good to me by myself and at lower volume.
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i think this virboking sound not good, because fender also use rubbish parts to this amp also,
Agreed. I'm appalled by fender's choice of caps in the signal path.
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What does he have on the power tubes ? It looks like it says power reducer on them ....Any way here is my thoughts on fender custom shop amps.....not point to point but a tag board by the way ...misnomer there....
I bought a new 64 vibroverb(reissue) about 5 or 6 years ago because of what I had read I believed they got it right, I still do.....when I opened it up (about a day after I got it ...I was a little disapointed in the size of the components compared to a real 64 ...but hey that was a misconception on my part of course they are smaller so are computers....I can not even Imagine the overhead that Fender has, so yes I expect them to charge a lot and buy the cheapest lots they can. They always have done that.....I purchased this amp as new it was supposed to have a blemish , but I can't find any, I can sell it at a pretty substantial profit today, but I won't.... I really like it....I rotate amps at home, but this is the one I gig with....not the thunderbolt or the marshall 50watt 800 and they are great really great sounding amps
the VV does it all .........Is it a vintage 64 vibroverb or blackface super ...no... I'd grab one of those if it presents itself but is it a great amp :worthy1: YES
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To rafe
Hi
I have some recommend for you. If you really like fender vibroreverb. I think you can sell it and bulid a new vibroverb of ptp or buy a vintage vibroverb from eBay . I help my friend to mod his Marshall bluebreaker. Because my friend hear my modified fender bassman. I change transformer to mercury, ptp board, weber speaker, sprague black beauty cap , ab resistor and sprague atom cap. the sound is Hugh different with original fender bassman, much much much better. Finally, I also change the same parts to his bluebreaker, he love it much too much.
To hotblueplate
Sorry for my post before, I say fender use rubbish parts. Because I pay $900usd to buy bassman. But my friend pay $2500, the parts is 100% same with my bassman . and the vibroking , the ptp board like pcb. The only different is that you can solder the part on the top of board. as the cap, it is fine. But I Just changed the cap to sprague atom and f&t. Sound already much better. Again, sorry for my word.
I have one question, when I insert the jack to vibroking channel input. It give some crack noise, just happen on channel 1 input only. How can I fix it, thank
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Because I pay $900usd to buy bassman. But my friend pay $2500, the parts is 100% same with my bassman . and the vibroking , the ptp board like pcb. The only different is that you can solder the part on the top of board.
Yes, the large price difference is because of the eyelet board instead of the PC board. And the "Fender Custom Shop" name.
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IIRC, both the Vibroking and Tonemaster were designed by Bruce Zinky, and both share a unique feature no other big Fenders do - no negative feedback!
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On their own, you might feel the amps sound stiff and bright. Good point. Maybe a bit of hijack, but I have a spider bridge Dobro with bone nut & saddles. In my living room it sounds too bright. But live in a mix, I get compliments on its tone. Glad I checked that out before modding to maple saddles.
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hi
i think the vibroking design is very good. just the parts is not good. (because vibroking parts is same with 59 bassman, but bassman just $900, vibroking $2500). in fact, fender is a company, they need to earn money. but i remember my mesa boogie dual rec, they use a good cap and resistor in their amp.
anyway, my friend want to make the vibrokign soudn better, so i will help him to change the cap. but i get one problem, when i insert the jack to channel 1 input, i get crack noise, how can i solve this problem
thank
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The big price difference is the labor, not the parts.
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Pretty neat. Although there are a couple different schematics for it, one of them looks like it's an amp with a Fender stand alone reverb unit built in before the first preamp tube.
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hi
i help my friend to change the cap. sound better now.
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3585.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3590.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/IMG_3586.jpg)
and i have one question, this amp have 1 6v6 tube. can i replace it to 6K6? because i remember fender old reverb unit is using 6K6 for reverb, not 6V6
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Yes. Sub the 6V6 to a 6K6.
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Maybe it's just the pic, but the 2'nd cap from the left, it's positive (+) connection looks really close to the ground buss. :dontknow: :w2:
Brad :icon_biggrin:
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hi
it is the photo problem, it will not touch the ground, thank you so much.
and do you mind to let me know what different of 6K6 and 6V6 for the reverb power tube?
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and do you mind to let me know what different of 6K6 and 6V6 for the reverb power tube?
Nobody currently makes a 6K6 tube. If you are a large manufacturer, you need to be able to buy tubes in large quantites at low prices. And you need to be sure your customers can find replacement tubes.
Other than that, the 6V6 is rated for higher voltage operation and more output power. I doubt a swap will make much difference, excpet for tonal differences between tubes. At least some amps of this type use a 6BQ5/EL84 instead of a 6V6. I see your amp has an octal socket with an adapter to use an EL84.
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hi
i get one problem. when i insert jack to input 1. i get crack noise. how can i solve this problem?
thank
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Clean the jacks and make sure the shorting function is working.
They need to short to ground when no cable is plugged in.Likely just dirty and corroded.