Anyone Tube Rolling with the Ultravalve??

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rcag_ils

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #20 on: 8 Sep 2011, 12:03 pm »
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Frank himself offered up op-amp rolling a couple of years ago.

I doubt that Frank found this by just rolling some op amps, he probably studied the spec sheet of the device, and determined the compatibility and result of the biasing ckt. Same with his tube upgrade, he probably studied the operating point and characteristic curves and all that stuff, instead of just pluging in tubes. Also I suspect a little tone control action would have accomplished the same thing.

What "rolling" mean is blindly plug in and unplug something into the exsiting socket just because it fits, without knowing what the hell he's doing. Then justify the result of the sound (if it didn't blow up) by using terms from the Stereophile magazine, calling it liquid, relaxing, tube like, buttery, syrupy and so on. Furthermore, have a log book going, and document the result of sound of the device that they have "rolled.

Brett Buck

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #21 on: 8 Sep 2011, 12:22 pm »
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We all know that there are "capacitor rolling", swapping out the capacitor and replace them with ultra expensive oil in paper cap with grounding copper foil.

     I can supply almost as many of those as they want. I remove them in old radios by the bucketful. Occasionally I will test them and so far not a single one of them was within a country mile of the marked value. Frequently they will initially test 5x the supposed value which seems odd until you check the DC resistance - which is most definitely not infinity. A goodly number of them on the power supply side have blown up and spewed their little guts all over the place like confetti.

   At one time I was keeping the old ones in a box on my workbench, I probably had something like 5 pounds of them before I tossed it.

 It's actually pretty amazing that a lot of these old radios still actually work, after a fashion, with dozens of leaky and grossly out-of-tolerance wax/paper capacitors in them. But to get almost any of them working "right", you have to get rid of them.

      I also note that NOS Sprague "black beauties" or "bumblebee" caps (paper/foil caps in  molded bakelite) are favored for "good sound" by some guitar players. That is probably a legitimate use since they are shooting to generate a sound they like. But I guarantee whatever you like about it today, it won't be sounding the same 6 months from now.

       Brett
     

rcag_ils

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #22 on: 8 Sep 2011, 01:29 pm »
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Wow, so basically, if your transistor count is under a zillion (and growing), then Silicon Valley will not return your phone calls? Surely the Bay Area audiophools must be able to do something about this?!

Audiophiles generally don't like to compare sound by de-solder, and resolder transistors, it may be too hard, or too time consuming for them. Also their general believes are tube sound better than transistor, so they don't bother with rolling the transistors.


simon wagstaff

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #23 on: 14 Sep 2011, 02:17 pm »
With the EL34 tube it seems that the "bubble" of sound is projected out into the room. Very  nice. with the KT77 it seems that the bubble is inverted and one looks "into" it.

Both perspectives are nice, depends upon what you like. I seem to prefer the EL34 sound but when the tubes finally blow up (i have been running them for a while now) I think I will be perfectly happy with the KT77.

Hydro

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #24 on: 19 Sep 2011, 01:35 am »
I tried some matched old stock Mullard El34's and the sound was ok but not great, East German El34's were horrible. The big bottle Cryo EH's sounded much better. The Mullard rectifier tube was the most solid sounding compared to a Japan made tube or Russian. The most difference for the better was the use of GE 6GH8A's. They seemed much more alive in their sound. Almost brought the Ultravalve up to the level of the Ultra350 I have hooked up to use in the same system. Then I got the Cryo Genalex Gold Lion 12AT7's for the Ultra350 and I now listen to the Ultra350 about 75% of the time. The Ultravalve has more natural vocals but the Ultra350 does everything else better. At least in my system. I am running them through a set of DIY Elsinore speakers and both amps are quite seductive.

Dynakitguy

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #25 on: 19 Sep 2011, 10:48 pm »
Hi all,
         There are not many tube rolling choices for the 6GH8A
 tube except one which I found and tried recently. This is the
 7687 tube which was used in a number of Scott amplifier as
 an upgrade replacement for the 6U8 and/or 6GH8A. Same 9AE
 pinout as the 6GH8A......Expect to pay upwards of $50 per tube
 if you can find them. Quite rare...Most are Sylvania branded.

 Kevin @ Dynakit

trackball02

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #26 on: 25 Sep 2011, 03:38 pm »
I swapped out the stock rectifier with a NOS Mullard. Wow, huge difference. I like the direction of the change. More body, three dimensional and velvety (not sure the best way to describe). I'll let this burn in. This is my first tube rolling experience, and a lot of fun. :lol:

I may try the GE 6GH8As, do you have a good source for purchase?

JerryM

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #27 on: 25 Sep 2011, 04:44 pm »
I swapped out the stock rectifier with a NOS Mullard. Wow, huge difference. I like the direction of the change. More body, three dimensional and velvety (not sure the best way to describe). I'll let this burn in. This is my first tube rolling experience, and a lot of fun. :lol:

I may try the GE 6GH8As, do you have a good source for purchase?

If it starts to sound crappy, or fatiguing, ride it out. Somtimes, that's break in.  :thumb:

Have fun,

Jerry

Hydro

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #28 on: 26 Sep 2011, 03:15 pm »
Trackball02, I got mine on the Bay. I also bought a spare pair since they were so "reasonable", about $10 each if I remember right. The GE's made more of a difference than the Rectifier. If you want to try out my spare pair you are welcome to, but I think you will end up getting some of your own. I did some tweeking on my crossover and raised the impeadence a little over the entire spectrum and the Ultravalve now sounds as good or better than the Ultra350. These amps really need to be matched with the speakers they drive to sound their best. Cheers TPate

trackball02

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #29 on: 27 Sep 2011, 02:52 am »
Hydro,
How did you choose the GE's? Did you try several brands?
I'm curious how you tweaked the crossover and impedance, was that through your preamp?
I'm running 16 ohm Zu Soul Superflys with my Ultravalve, and it seems that is is a great match.
Jay

Hydro

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #30 on: 27 Sep 2011, 03:12 pm »
From what I can tell, only three manufactures made this tube in the US. GE, Sylvania and Tung Sol. I haven't found a Tung Sol to try but did try the Sylvania's. The Sylvania's were better than the "stock" tubes, but not much. The sound with the GE's fit my taste so I quit looking.

Hydro

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #31 on: 27 Sep 2011, 03:25 pm »
Jay, Concerning tweeking the crossovers, the Elsinores are a DIY speaker that is really made to be run by a tube amp. Very flat impeadence and very little phase shift. I have a friend in the speaker business and we ran tests on the speakers parameters. He suggested some changes in the published crossover that made them an easier load for the amps. I don't run a preamp, CD based system only, no phono. I use a DIY 100k stepped attenuator from Glassware.

simon wagstaff

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #32 on: 27 Sep 2011, 11:20 pm »
I swapped out the stock rectifier with a NOS Mullard. Wow, huge difference. I like the direction of the change. More body, three dimensional and velvety (not sure the best way to describe). I'll let this burn in. This is my first tube rolling experience, and a lot of fun. :lol:

I may try the GE 6GH8As, do you have a good source for purchase?

Did you put in the diodes? I am thinking they make the rectifier tube less critical.

trackball02

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #33 on: 28 Sep 2011, 12:07 am »
I believe that my speakers do not have crossovers due to the full range driver so any crossover adjustments would not apply to my system.

No, I did not put in any diodes. My Ultravalve was built this January. Can I assume that no diode modifications are needed, since this is a newer version?

Lefty052347

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Re: Anyone Tube Rolling with the Ultravalve??
« Reply #34 on: 28 Sep 2011, 12:34 am »
Your Ultravalve has the diodes.

Regards,
Dean

rlee8394

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #35 on: 1 Oct 2011, 04:06 am »
I've been using these and like 'em!!  :thumb:

http://www.vacuumtubes.com/6BG6.html


At $48/quad you can't go wrong.

Ron

trackball02

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #36 on: 9 Oct 2011, 05:51 pm »
Ron,
Interesting. Are you running this conversion on the Ultravalve?
How did this change the sound?
Are there any bias issues or changes in the power output?
Thanks, Jay

rlee8394

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #37 on: 10 Oct 2011, 08:54 pm »
I'm using these in my two Ultimate 70's that I built from Frank's kit. They bias up just fine, have a greater plate dissipation than el34s, and sound great. I am using them with the adapter sockets right now. You can see them on my gallery. I want to try some Shuguang KT-66's for comparison. If I think it's too close to call, I'm going to rewire the sockets to use the 6BG6GAs. I've written instructions on rewiring the sockets. If anyone is interested I'll post them.

I think that the sound is much more immediate if you know what I mean. Plenty of bass, great separation, etc. I don't notice any power differences, but then again no one would unless measured on a o'scope. Of course only your ears can decide for you. If cost of the tubes are of any concern, then I don't see how you can beat these.

Ron

trackball02

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #38 on: 11 Oct 2011, 04:51 am »
Ron,
Sounds like a cost effective upgrade.
Right now, I have a pair of GE NOS 6GH8As on order, I'm going to try them out first, see how it sounds, then play around with the power tubes. I was thinking of trying the JJ 6CA7s which seem to have some nice reviews. Not that expensive. Might be fun to compare with your suggested 6BG6GAs. Aren't tubes fun?
Jay

rlee8394

Re: Anyone Tube Rolling with the Ultravalve??
« Reply #39 on: 11 Oct 2011, 07:30 am »
Yeah, that's a new tube that they just released. I would like to know how they compare to the EH 6CA7s. Since Frank uses JJ tubes for some of his products, I wonder if he'll get some in to try and report back. Would be nice. But you gotta love the look of the KT-66s!! :thumb:

Ron