LIO Tube Stage

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BrentG

LIO Tube Stage
« on: 10 Nov 2014, 05:17 pm »
Vinnie,

I have a question on the LIO tube stage…

The LIO tube stage uses a pair of tubes - one tube per channel. How closely matched should the tubes be?

Thanks,
-Brent

Vinnie R.

Re: LIO Tube Stage
« Reply #1 on: 11 Nov 2014, 05:24 am »
Hi Brent,

Quote
The LIO tube stage uses a pair of tubes - one tube per channel.

Correct - and both sections of each tube (6922 dual triode) are used in this circuit.

Quote
How closely matched should the tubes be?

As close as you want them to be.  :green:   Seriously, it won't hurt anything if they are not closely
matched, but you could end up with audible channel imbalance.

For the stock tubes, I test them in the circuit and make sure output voltages of each channel do not vary more
than 0.5dB.   For example, if the output of one channel is 1V, the output of the other should be > 0.94V and < 1.06V. 

- Vinnie

roscoeiii

Re: LIO Tube Stage
« Reply #2 on: 11 Nov 2014, 07:39 pm »
Plus any of your volume control options also have balance control right? Which could compensate for tube differences...

Vinnie R.

Re: LIO Tube Stage
« Reply #3 on: 11 Nov 2014, 09:42 pm »
Plus any of your volume control options also have balance control right? Which could compensate for tube differences...

Yes - excellent point!  :thumb:

BrentG

Re: LIO Tube Stage
« Reply #4 on: 14 Nov 2014, 04:05 pm »
Hi Brent,

Correct - and both sections of each tube (6922 dual triode) are used in this circuit.

As close as you want them to be.  :green:   Seriously, it won't hurt anything if they are not closely
matched, but you could end up with audible channel imbalance.

For the stock tubes, I test them in the circuit and make sure output voltages of each channel do not vary more
than 0.5dB.   For example, if the output of one channel is 1V, the output of the other should be > 0.94V and < 1.06V. 

- Vinnie

Thanks, Vinnie. That's what I needed to know. I'll order a matched pair of tubes for my LIO.

-Brent

christopher3393

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Re: LIO Tube Stage
« Reply #5 on: 26 Nov 2014, 08:31 pm »
Hi folks, I've ordered a LIO with tube stage. I'm new to tubes. I've read the Red Wine tube thread and 2 tubes stand out as likely best for my taste:

Miniwatt Dario 7308

Amperex 6922 Pinch Waist

I'm having trouble finding the Dario except on Ebay. The Ebay sellers are all European, mostly eastern Europe. I"m feeling cautious about this. Brent Jessee does have a pair of Mazda 7308s, some of which are labeled Dario (http://www.audiotubes.com/6dj8.htm, scroll down to Mazda).

As for the pinch waist, Brent Jesse also has a pair of these. Really spendy, but if this is what it takes to sound best, I'm ok with it. HOWEVER, when I checked Upscale Audio I found the following comment:

" The very first 6922's made by Amperex had a pinched waist and they're horrible quality.  90% of them are microphonic, and if they aren't now they will be in a few months." ( http://www.upscaleaudio.com/amperex-6922-tall-bottle-1960s-vintage-made-in-usa/). Yikes!

There may be related tubes that I'm missing, so any help with this is appreciated.

The reason I want to move relatively quickly to something upscale from the stock JJ is that I want give the LIO the best opportunity to shine in my system during the first 30 days. I would certainly not want to return it because I hadn't tried an expensive/excellent pair of NOS tubes suited to my taste.

Thanks in advance,

Christopher

HPDJ

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  • Posts: 44
Re: LIO Tube Stage
« Reply #6 on: 30 Nov 2014, 06:39 am »
LIO is a new kind of beast, but I know that with my RWA Signature 16 the stock tube works wonderfully for me....and I tried a fancy NOS tube...and it just didn't do it for me in my system. I think Vinnie's products are different than some other manufacturers products where practically everyone does away with the stock tubes to upgrade the sound. Plenty of folks have reported upgrading the stock tube of RWA gear, and loving the results....and there are some (like me) who love the stock tube. I will explore other tubes eventually but I'm not in a hurry because the amp sounds great in my system as is.  This may all be different with LIO, I don't know...and I do get the logic of trying to get "the best" tube for your system within the 30 day trial period. But it's not necessarily a guarantee that a NOS tube will improve the amps performance. That's all I'm saying :)

Should you want to move forward with purchasing some tubes from Brent Jesse to try with your incoming unit, I'll vouch for his excellent service and say that he is very trustworthy and is very clear and honest via email/phone if you have questions. Great person to deal with, and he has one of the best return policy's in the tube world period. Meaning, you can return a tube within a certain period (I forget how long exactly) even if you just don't like the sound that tube is imparting to your system! Most others will let you return a tube...only if there is something wrong with it, or it just dies within a specified period of time. I've returned some tubes to him that I just wasn't feeling in my set-up and they took them back, no questions asked. (Check his site for more details, I think there is a reasonable restocking fee with returns.) Because of this I always check and see if he carry's any tube I'm interested in. [I've no affiliation with Brent Jesse btw]..

Can't wait to start reading some impressions of the LIO, it looks very promising and the prototype I saw/heard at the NY Audio Show worked really well with the Harbeth speakers they had in the room :)

ralpheburns

  • Jr. Member
  • Posts: 39
Re: LIO Tube Stage
« Reply #7 on: 1 Dec 2014, 02:18 pm »
Christopher,

I feel the same way as you, and enjoy doing business with Brent Jessee.  I'm not a fan of the JJ tubes, and Vinnie suggested three tubes to try in the LIO, and he suggested to start with the Telefunken, but all three are tempting.

http://www.upscaleaudio.com/telefunken-e88cc-6922/
 
http://www.upscaleaudio.com/amperex-7308-vintage-gold-pin/
 
http://www.ebay.com/itm/E88CC-CV2492-MULLARD-MILITARY-NOS-BOXED-/260577827114?pt=UK_Sound_Vision_Valves_Vacuum_Tubes&hash=item3caba6192a

Hope that helps - Ralph


brh

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  • Posts: 102
Re: LIO Tube Stage
« Reply #8 on: 1 Dec 2014, 02:31 pm »
I'm planning to give the Telefunkens a whirl in mine first, and probably try out a set of Siemens 6922s as well. In my experience (with my Sig 16 and others) JJ tubes are quite a feat - they perform quite admirably for the price. But some of the more exotic tubes out there do kick it up a notch, in my opinion.

christopher3393

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Re: LIO Tube Stage
« Reply #9 on: 1 Dec 2014, 03:22 pm »
Thanks for the replies. Much appreciated and helpful. Looking forward to learning more.

HPDJ

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Re: LIO Tube Stage
« Reply #10 on: 1 Dec 2014, 05:27 pm »
brh,

What other tubes have you tried in your signature 16 so far?

I can't wait to read your impressions of the LIO since you have a S16 right now and will be able to compare the two :)

Vinnie R.

Re: LIO Tube Stage
« Reply #11 on: 1 Dec 2014, 07:58 pm »
All,

I highly recommend that you start off with the stock JJ E88CC tubes in your LIO.  Allow for at least 100 hours of burn-in if you can, and then decided if you want to play with tube rolling.  Even if you already *know* that you want to play with tube rolling, it is good to have a starting point.  Then you can share your findings here!

I'd say that over the years , at least 50% of my RWA customers never had the urge to tube roll - they were very content with the stock tubes.  For those who like to experiment (I'm definitely in this camp!), there are a lot of options out there.

The Upscale Audio Telefunken E88CC's are very good for the price (and I do expect the price to only rise over the months) and take the performance of a notch over the stock JJ's in regards to top-end extension and openness to the sound.  To me, they are closer to neutral sounding - not a very warm / rich (but they do have some of this!) and not bright either.  They walk that fine line in the middle and do it well.

The MiniWatt Dario E188CCs, Amperex 7308 "PQ"'s, and Mullard CV2492's are richer in the midrange, and more seductive.  I love these tubes, but I do need to spend more time listening to them all in the LIO.  I will need to start a new "LIO Tube Rolling" thread in this forum soon enough, and we can all contribute our findings there with tube rolling with the LIO. 

Down the road, I do plan to experiment with other tube families besides the E88CC/6922 family, and hope to offer different versions of the LIO Tubestage.  LIO customers could try the module (with 30-day refund policy) and see how they like it compared to the 6922 version.  This is what the LIO is all about - our customers being able to quickly try our latest offerings without having to ship their LIO to us for upgrade.  You just plug-n-play.  2015 is going to be a lot of fun!  8)

Thanks for all your posts!

Vinnie

brh

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Re: LIO Tube Stage
« Reply #12 on: 14 Dec 2014, 06:19 am »
brh,

What other tubes have you tried in your signature 16 so far?

I can't wait to read your impressions of the LIO since you have a S16 right now and will be able to compare the two :)

Sorry I haven't responded sooner, just been busy. I gave the stock JJ a fair bit of time in the Sig 16, of course, as well as a 12v (5751) JJ… both performed similarly, fine, safe… I'm glad JJ tubes exist. But, on to the fun stuff!

I actually ran a Yugoslavian RCA 12AX7A in the Sig 16 for quite some time. I pulled it from an old shortwave kit radio, and that tested shockingly well given the condition of said radio (which, to be fair, worked beautifully despite looking like I'd pulled it out of the ground). But, fun reminiscence aside, that's neither here nor there since (for the time being?) the LIO only gets 6v tubes.

In the relatively-affodable category, I was incredibly impressed with the performance of the Philips JAN USA 6922. $30 tube, and I left it in the Sig 16 for a while, felt like the bass may have been a bit lean, which is an issue with my Audience speakers. But it was very listenable, and as I said, listen I did, for quite some time. I might get a second one (matching, be damned!) for LIO just for kicks.

I've also run the Telefunken E88CC, which is just… an awesome tube no matter what you're putting it in.

Currently I have the comparably awesome Siemens CCa inside Sig 16, and have (as one would expect) no complaints.

So what goes in LIO when she (she's a she, right? she's name after three ladies after all…) arrives? Well, the CCa has a cute twin, and my Telefunkens are a twosome as well. I also have a set of National (MiJ) 7DJ8s that I have yet to try in Sig 16 for whatever reason, but which will certainly make their way into LIO. And, as I said, I may very well get a friend for the Philips JAN. Should tide me over for a while.

I'll definitely contribute to the inevitable LIO tube rolling thread, so… check back in January, I guess! :)

Stercom

Re: LIO Tube Stage
« Reply #13 on: 14 Dec 2014, 01:26 pm »
I recommend a pair of Amperex 8416 PQ (it's like their 7308, but with a 12V heater).  This is the tube Vinnie recommended for my Signature 57 and its excellent.

Vinnie R.

Re: LIO Tube Stage
« Reply #14 on: 15 Dec 2014, 08:20 pm »
Quote
So what goes in LIO when she (she's a she, right? she's name after three ladies after all…) arrives?

Hi brh,

YES  :wink:

Quote
I recommend a pair of Amperex 8416 PQ (it's like their 7308, but with a 12V heater).  This is the tube Vinnie recommended for my Signature 57 and its excellent.

Hi Stercom,

The 8416PQ is indeed an excellent tube, but this first iteration of the LIO Tubestage is only compatible with the 6922 family (6.3V heaters).  So these will work:

6922/E88CC, 6DJ8/ECC88, 7308/E188CC, 7DJ8/PCC88, 6N23, 6H23, 6N11, and 6GM8

NO 6H30, and no tubes with 12V heaters. 

But always a possibility with future LIO Tubestage designs (along with different tube families)... we'll see.

Vinnie

Blu99Zoomer

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  • Posts: 204
Re: LIO Tube Stage
« Reply #15 on: 21 Dec 2014, 06:51 pm »
Hi Vinnie,

I am enjoying reading the comments from everyone regarding their experiences with tube rolling in their LIO tube stage and  LFP-V Edition equipment.  I have a newbee question.  I have a Signature 15 LFP-V Edition amplifier that I got from you last fall.  It is not the integrated version.  This still has a tube stage?  I thought that the tube stage was located in the preamplifier section of the integrated versions.  Since this is a "tube" question, I didn't know where else to post it.   Thanks.

Blu99Zoomer

Vinnie R.

Re: LIO Tube Stage
« Reply #16 on: 22 Dec 2014, 04:49 pm »
Hi Vinnie,

I am enjoying reading the comments from everyone regarding their experiences with tube rolling in their LIO tube stage and  LFP-V Edition equipment.  I have a newbee question.  I have a Signature 15 LFP-V Edition amplifier that I got from you last fall.  It is not the integrated version.  This still has a tube stage?  I thought that the tube stage was located in the preamplifier section of the integrated versions.  Since this is a "tube" question, I didn't know where else to post it.   Thanks.

Blu99Zoomer

Hi Blu,

Yes, your Sig 15 power amp still has a tube stage (there is still a tube buffer, but no volume control or input select before it on the Sig 15 power amp version).

Your post is sort of related to a LIO Tubestage question I received a few times, so I'll post it here:

Q: "What is the difference between the LIO Tubestage module, and the tube stage in my RWA component?"

A: For Red Wine Audio components, there is the Isabella LFP-V / Isabella Renaissance Edition (preamp) topology, which uses 1 tube per channel.  The other RWA components (LFP-V and R.E.) used a tube buffer, with 1 tube for both channels.  No voltage gain with the buffer - only current gain.

LIO's Tubestage is more similar to the Isabella in that it also uses one dual-triode tube (E88CC / 6922 family) per channel, with both sections of the dual-triode used per channel.  But the circuit topology is even more advanced with things like constant-current sources, ultra-low noise linear voltage regulation (instead of standard 317 adj. regs), current regulators of tube heaters, and a few other refinements.

LIO's Tubestage is my best sounding tubestage offering to date!  So simple (pure Class A, low parts count, shortest signal path lengths), yet so complex in what it offers the listener.  Down the road, it will be very hard to top it - but you know that won't stop me from trying.  8)
And later on, I do plan to look into offering other tube stage modules (different tube families and designs).

Also note that LIO's Tubestage is ONLY compatible with tubes in the 6922 family (no 6H30 - as they are too tall to fit and the tube heater current regulators are not set for the 6H30's higher tube heater current requirement.  And no 12AX7).

- Vinnie
« Last Edit: 21 Feb 2015, 04:46 pm by Vinnie R. »

radarnyc

Re: LIO Tube Stage
« Reply #17 on: 21 Feb 2015, 12:14 am »
Is the tube stage for the mosfet amp only or also the headphone amp?

Vinnie R.

Re: LIO Tube Stage
« Reply #18 on: 21 Feb 2015, 04:33 pm »
Hi radarnyc,

LIO Tubestage follows the volume control, so it is used for both headphone and speaker outputs, as well as
the variable line outputs ("preamp outs").

Vinnie

OzarkTom

Re: LIO Tube Stage
« Reply #19 on: 21 Feb 2015, 05:23 pm »
Hi radarnyc,

LIO Tubestage follows the volume control, so it is used for both headphone and speaker outputs, as well as
the variable line outputs ("preamp outs").

Vinnie

Vinnie, do you any sonic comparisons of the tube stage and the autoformer stage?