synchro
Joined: Feb 02, 2008
Posts: 4464
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Mar 30 2018 08:13 AM
Tqi wrote:
synchro wrote:
Vox is making amps with something they call NuTube technology using vacuum-fluorescent displays as a triode.
A dual-triode, even! I think they need about ±50V? So about the same as most power op amps or Mosfets. You can buy them on Mouser if you're interested in giving one a shot for an experiment! Would be pretty cool to see someone make a '63 clone using NuTubes - a little superfluous given what with have available now, but cool to see anyway. A NuTube/Mosfet Brownface amp would also be cool to see. Something like the Vox Valve Reactor, where an all-NT preamp is followed by a push/pull NT poweramp, which is then fed into a class D amp to colourlessly amplify it to 100W.
The odd thing about NuTube is that Korg hasn't made a lot of products with it yet. The AC30VR is still using an ECC83, for example.
I think that’s about right, with regard to the voltage. The MV-50 has a class D power amp and puts out 50 watts into 4 ohms, the entire amp being roughly the size of two compact-format effects pedals. I’ve heard mixed reviews, some people love them, but one player whom I respect felt that the MV-50 sounded weak and thin. There are none to be found around here, so I can’t test one in person unless I’m willing to buy one . . . And I’m not quite ready to do that. Having something on the order of eight amps, I’m not exactly hurting in that department.
At this point, I’m watching with great interest, however. It might fizzle, but it could be the next step forward in amplification. What interests me is that this thing is a vacuum tube, albeit much different than the tubes we are familiar with. Having a low-voltage tube available could be a game changer. Personal computers would not have been possible without the switching power supply. This one component is often taken for granted, but it’s as much the reason that computers were possible to produce in a small package as was the microprocessor. At the very least, the NuTube bears watching, IMHO.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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dragonsurfer
Joined: Apr 17, 2008
Posts: 128
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Posted on Mar 30 2018 12:10 PM
A DR with a Mosrite will get you The Fabulous Ventures album tone in a large venue.
And the NuTube technology might be a spin-off from Vox's Valvetronix amps where a 12ax7 is used in circuit and "sampled" as a reference of sorts to allow the circuitry to emulate a tube, not that the tube is passing audio through it.
Last edited: Mar 30, 2018 12:24:00
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Tqi
Joined: Dec 07, 2014
Posts: 1222
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Posted on Mar 30 2018 12:32 PM
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Last edited: Feb 02, 2024 13:24:32
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dragonsurfer
Joined: Apr 17, 2008
Posts: 128
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Posted on Mar 30 2018 12:40 PM
Tqi wrote:
dragonsurfer wrote:
where a 12ax7 is used in circuit and "sampled" as a reference of sorts to allow the circuitry to emulate a tube
That's not how that works.
the tube is passing audio through it.
That's exactly what it's doing.
The 'Valve Reactor' amps use a 12ax7 in push-pull as a power amp stage; then simply amplify the result. There's no magic digital trickery.
Here's the schematic if you want proof. Look at the power stage.
www.valvetronix.net/docs/AD15_30Servicemanual.pdf
A Nutube 6P1 is just a dual triode with different specifications, like other ultraminiature triodes before it.
Then their advertisement of the Valvetronix amps is faulty as that's what I read. I used to have the AD50VT. And in swapping out the factory EH12ax7 to an old vintage Telefunken the tone changed on the amp. I took the Telefunken out when I sold it.
So the audio is actually going through the tube in this case?
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Tqi
Joined: Dec 07, 2014
Posts: 1222
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Posted on Mar 30 2018 12:53 PM
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Last edited: Feb 02, 2024 13:25:17
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synchro
Joined: Feb 02, 2008
Posts: 4464
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Mar 30 2018 03:05 PM
Tqi wrote:
A Nutube 6P1 is just a dual triode with different specifications, like other ultraminiature triodes before it.
That's it. Someone realized that these could be adapted for use as a triode and they made it happen. As I understand it, they had to jump through some hoops, but it did work out in the end.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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Tqi
Joined: Dec 07, 2014
Posts: 1222
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Posted on Mar 30 2018 03:37 PM
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Last edited: Feb 02, 2024 13:25:29
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synchro
Joined: Feb 02, 2008
Posts: 4464
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Mar 30 2018 03:46 PM
Tqi wrote:
They're quite affordable, too. About the same ballpark as a high end new 12ax7. It has a gain factor of about 15, compared to a 12ax7's 100 and a 12au7's 19 (lowest in the family).
Also, since it's my first chance to use it...
 
In the MV-50, it’s sandwiched between a pair of op amps, which gets the gain up there, but retains the tube’s character. The samples I heard sound great.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
Last edited: Mar 30, 2018 15:47:00
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Tqi
Joined: Dec 07, 2014
Posts: 1222
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Posted on Mar 30 2018 04:06 PM
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Last edited: Feb 02, 2024 13:25:49
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synchro
Joined: Feb 02, 2008
Posts: 4464
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Mar 30 2018 10:46 PM
Tqi wrote:
That was the idea I had as well, while reading the data sheet: lots of tiny class D op-amps to give the tubes enough signal to drive naturally.
It's a little beyond my electronic engineering knowledge though, and no doubt Björn could achieve the same quality with no valves at all. ;)
I probably will end up with an MV-50, just out of curiosity. I really want to hear this for myself. If it actually sounds like an AC-30: bonus! They also make MV-50s voices like a clean Fender and like a Marshall.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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Tqi
Joined: Dec 07, 2014
Posts: 1222
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Posted on Mar 31 2018 03:51 AM
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Last edited: Feb 02, 2024 13:26:27
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synchro
Joined: Feb 02, 2008
Posts: 4464
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Mar 31 2018 08:54 AM
Tqi wrote:
Though, it does look like each voice is a separate amp, which I prefer but wallets don't!
Indeed. For my purposes, the Marshall, High Gain and Boutique are out of the picture, I’m not into distortion, so there are only two, the AC and the Clean, so for $400 one could have two 50 watt heads.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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Pablomago
Joined: Mar 23, 2017
Posts: 85
Fort Collins, CO/Moonstone Beach, CA
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Posted on Apr 01 2018 10:33 PM
Back to making small amps louder.
Back in the '70's Don Felder with the Eagles used two Tweed Deluxe amps. Even mic'ed, playing stadiums, it wasn't enough. So they mic'ed the Deluxes, ran the signal into an Alembic tube preamp (that was basically a Showman preamp in a single rack unit) ran that into a Crown DC-300 power amp pushing an Alembic B-15 cab with two JBL D-130's. And that was his stage rig. I think there was an Echoplex and a Boss CE-1 in there somewhere as well. Then the Alembic cabs were mic'ed and run into the PA.
Just throwing out another way to get the stage volume up!
— All opinions expressed by this poster are well thought out and based on actual experience and/or scientific experimentation, except for those which are knee-jerk reactions or good sounding fantasies.
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Matt22
Joined: Feb 15, 2007
Posts: 2845
Fredericksburg, Virginia
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Posted on Apr 02 2018 01:10 AM
synchro wrote:
Indeed. For my purposes, the Marshall, High Gain and Boutique are out of the picture, I’m not into distortion, so there are only two, the AC and the Clean, so for $400 one could have two 50 watt heads.
I have the AC coming in early this week. I'll let you know what I think, but I was amazed at the A/B demos with an AC-30 and couldn't tell the difference.
— Matt "tha Kat" Lentz
Skippy and the Skipjacks: 2018-2020
Skippyandtheskipjacks.net
https://www.facebook.com/skippyandtheskipjacks
Otto and the Ottomans: 2014-2015
The Coconauts surf band: 2009-2014
www.theamazingcoconauts.com
Group Captain and the Mandrakes 2013
http://www.gcmband.com/
The Surfside IV: 2002-2005, 2008-2009
the Del-Vamps: 1992-1999, 2006-2007
http://www.dblcrown.com/delvamps.html
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dragonsurfer
Joined: Apr 17, 2008
Posts: 128
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Posted on Apr 02 2018 03:36 AM
Open back combo amps lose sound projection.
The photo below was Stephen Still's stage solution to micing his vintage tweeds. The barricade (which is part of their touring gear) behind the amps was then covered with a thick blanket pad to contain the sound as the amps sat inside this acoustic "horn." Still's choice of vintage small amps needed a way to enhance the volume.
Note everything is miced and a rack containing Alembic preamps (not seen) with a black Fender tank sitting on top was also part of Still's rig.
There were other things going on like a THD Hotplate.
On the other side of the stage Crosby used two VibroKings miced.
Nash used a single Magnatone.
A small wattage open back combo will get lost, does not have the watts to overcome the phase cancellation of the front and rear wave, losing bass frequencies which is why a closed back cab has a better chance of projecting vs an open back and reason why a Twin's 100 watts will survive the stage volume even though much of its power is being cancelled, over the smaller combo amps.
Unless one goes solid state with these new versions of power amps that are small, light and powerful, you'll be back to sloughing heavy vintage amps and cabs to reamplify your stage main rig.
This was from a CSN production I worked on.
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synchro
Joined: Feb 02, 2008
Posts: 4464
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Apr 02 2018 08:22 AM
Matt22 wrote:
synchro wrote:
Indeed. For my purposes, the Marshall, High Gain and Boutique are out of the picture, I’m not into distortion, so there are only two, the AC and the Clean, so for $400 one could have two 50 watt heads.
I have the AC coming in early this week. I'll let you know what I think, but I was amazed at the A/B demos with an AC-30 and couldn't tell the difference.
I’ll be looking forward to hearing about that. If they can sell something that sounds like an AC-30 for $200, that is an amazing development.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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