Message started by grinnell on 03/15/13 at 02:52:14

Title: Rolling tubes
Post by grinnell on 03/15/13 at 02:52:14

Damn so far i have switched a bunch of tubes around in this thing and nothing sounds bad, different maybe.

Just dropped in a pair of RCA 6v6g st circa 1946, looks sweet with that coke bottle shape.  Sound seems to be a bigger soundstage with more depth then the reflektor 6v6gt.  

next the elusive blue glow of the OB3.  

Title: Re: Rolling tubes
Post by Fireblade on 03/15/13 at 13:24:17

Interesting ... How an output tube sounds in the Mini will of course depend mostly on the accompanying driver and output voltage regulator combination.

Title: Re: Rolling tubes
Post by grinnell on 03/15/13 at 13:34:52

Keep them the same, E180CC – Philips and GE OB3.  Found little to no difference btw an OA3 and the GE OB3.

Title: Re: Rolling tubes
Post by Fireblade on 03/16/13 at 02:52:01

Thanks for the tip, Grinnell. I'm planning on trying some Russian OA3's and an OB3 also.

Quote from NOS Electron Tubes:

"E180CC is very close to ECC81 / 12AT7 familly, especialy similar to E81CC / ECC801S premium types, a bit lower gain, long life tube with expected life of 10000 hours, made in Holland, three ribs plates. Very musical tube, great for audio use!"

I believe 'Gotog' from this forum had suggested this driver (also called 7062) in the past. My only concern with this well rated driver is the higher plate current, but since Steve has apparently approved its application in the Mini, there should not be a problem with it.

Re the RCA 6V6, where did you find it?

Title: Re: Rolling tubes
Post by grinnell on 03/16/13 at 06:48:26

I bought Gotog's mini so it his phillips 7062's in there.

I got the RCA 6v6g's off ebay from a tube guys with good ratings and sells lots of tubes  pm for name.

I bought the OB3's for the purple glow lol  

Title: Re: Rolling tubes
Post by Gotog on 03/16/13 at 17:26:06

Just wanted to add that I really enjoyed the 7062 in the Mini Torii with 6v6s tubes.  Needing a little more gain than the 12au7 and not being a fan of 12at7's, in general,  I gave the 7062 a try based on reading Tybee's post back in 2011...  his finding are noted below, and I had the same experience...  I found that there were no issues with amp heating up with these tubes...  I miss having the mini torii around..

From Tybee's post

"...I have been tube rolling input tubes with the Mini Torii, and I have found a favorite tube for now, the Amperex 7062.  My tube rolling of 12AU7s, 12AT7s, etc, were frustrating as I felt that the best from the MT had not occurred when compared to my other SE amps.  I discovered in my tube stash the Amperex 7062s and decided to give them a try and wham!  The MT came alive.  The sound became more dynamic, with more inner detail starting to reveal itself. On good recordings, the soundstaging and instrument/performer was much clearer and identifiable. My Tonian TL-D1 speakers are known for their excellent reproduction of percussion and the addition of the Amperex 7062 has provided the best percussion that I have experienced. almost live..."

Title: Re: Rolling tubes
Post by Fireblade on 03/16/13 at 19:54:43

Love this topic!

Well, my experience with the sometimes edgy but otherwise efficient detail-retrieving and sound opener Brimar 12AT7, has been very good.

The important thing with this driver is being able to couple it with the right 6V6, which in my particular conditions, has to be a tad warmer than neutral to work out the synergy.

If the 7062 is not as aggressive, then I suppose the 6V6 could be on the neutral side, like the current production Tung-Sol 6V6, which is very fast & transparent, but may go overboard in high-pitch passages with the 12AT7.  The 7062 profile may thus offer several other potentially synergistic 6V6 alternatives.

Les Lammers has suggested replacing in this same configuration the OA2 input VR (replacing the ubiquitous OC2), keeps the Tung-Sol 6V6 under control and thus at its best. He's probably right, I'll check that option.

I still think the 6V6 has to be a tad warmer with plenty of detail for my own tastes, but that's only because of my 12AT7 driver's profile. It could well be the 7062 is a set changer in my rig, and now I really need to try it.

Title: Re: Rolling tubes
Post by grinnell on 03/17/13 at 16:08:10

" configuration the OA2 input VR (replacing the ubiquitous OC2), keeps the Tung-Sol 6V6 "

Which VR tube regulates the output tubes?   Do the Ox3's or the Ox2's?

I thought the OA2's regulate the drivers.  

But i can't read a schematic  lol

I have changed VR and output tubes and have heard minor changes, the biggest asi mentioned is the older 1940's RCA 6v6G ST having a deeper soundstage.

I have the stock JJ 12au but a number of 12au NOS tubes I may try swapping in and out to play with.

Title: Re: Rolling tubes
Post by Fireblade on 03/18/13 at 00:25:30

The OC2 and OA2, are indeed input stage VR's, but they can also affect the entire tube set. All tubes have, to a larger or lesser extent, an impact upon the rest, as do ancillary equipment.

The suggestion that came from Less, after he tried it, is that replacing the OC2 (75 mV, stock) with an OA2 (150 mV), he experienced better behavior from what I consider a borderline bright Tung-Sol 6V6 (neutral and transparent, fast, but tends to be too bright when pushed into higher frequencies).

Now, Less's configuration is very different from mine, but since we both have Mini's and these have relatively few tubes, chances are his findings may be applicable in my configuration also.

The OA3, OB3, ... , OD3 are output stage VR's, and although they work more closely with the output tube, they typically impact the entire tube set, so finding VR synergies, in particular with the driver and especially the output tube, is very important.

These are just my own opinions, based on my recent, long, tube-rolling experience with the Mini, in my particular setting.

I hope this clarifies the issue for you.

Title: Re: Rolling tubes
Post by grinnell on 03/18/13 at 16:57:40


the fact that there are 5 x2 different tubes to play with and some of them are pretty inexpensive make this a fun amp to play with.

Title: Re: Rolling tubes
Post by Lon on 03/18/13 at 17:01:02

The Torii Mk III is fun to tube roll for the same reason. ;)

Title: Re: Rolling tubes
Post by Fireblade on 03/18/13 at 21:19:08


The main advantage with the Mini is that it is a SEP amp, and each tube has a unique (not shared) role within the configuration. This makes each tube a fine-tuning instrument.

The fact that it is also quite robust (accepting many possible alternatives per tube position and still sounding good), makes it a nice tube-rolling platform. Like you have pointed out, since it is a 6V6-based amp, rolling costs are moderate.

Title: Re: Rolling tubes
Post by Lon on 03/25/13 at 12:32:02

I'm enjoying two RCA OB2 in my Torii right now, nice balance for me and my current tube complement. I have OA2 to try as well but wasn't initially impressed, but these are all unused tubes, I'll burn them in in the second system soon.

I think every tube in these amps matter (just conjecture with the MT but I wouldn't be surprised if that were true as it's true of every Decware amp I've had). Fascinating, maddening, wonderful.

Title: Re: Rolling tubes
Post by hifitubes on 01/12/14 at 09:57:58

Anyone try the re-issue Gold Lion 6V6GT?

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