[nodiak]

Ashok brought up the Tubalizer in another discussion ("What Octal tubed preamp..."). Thanks Ashok for the idea.
AFAIK he is away for a few more days and has not tried his Tubalizer yet. I was going to wait for him to start a thread but because of some problems I had hooking mine up I thought I better get out a warning about using the 92-009 switching power supply that Autocostruire recommends and sells to use with the Tubalizer in the USA.

Using the 92-009 ps produces a HUGE amount of 60hz hum making it the wrong choice for using it in the USA, IN MY EXPERIENCE. I have no idea if it could be otherwise for anyone else in the usa (can't see how), but this is how it went for me.
So I went down to Radio Shack and picked up a 12V 1000mA power adapter (273-1776) and it still has some hum, but only audible during pauses in the music. Still even this amount of hum can be heard lightly  at 15 feet during playback silences! Just a bit too much. My other pre's don't have this problem. A tube problem? The Sovtek 6SL7 they included is poorly assembled. The glass is actually set at an angle, resembling the leaning Tower of Pisa!
If not just the tube I do suspect that a better ps ,or a mod by someone with electrical abilities, could take care of this problem. I did try it plugged in straight to the wall outlet as well as through a Tripp Lite Isolation Transformer, there was no difference.
I will email Autocostruire about my experience to see what they think is a good solution.

Ignoring the hum, it sound very good. More on that later.

http://www.autocostruire.com/catalog/product_info.php?products_id=304&osCsid=060f0d3b015b495637563bd385b49267



Don

[nodiak]

I got the Tubalizer as a cheap way to get some experience with Octal tubes in the mix. I know all Octal units will sound different so I don't expect this to represent anything but itself in the end. But what the hell, it cost ~ 110usd delivered (in 4 days!). The Rad Shack wall wart was $20.
 
I have an upgraded MinMax pre to compare it to. I have only a little tube gear experience and to me the Minimax is more on the expansive and open end of the spectrum, and as it is famous for, responds to tube rolling well. It is an obviously very good pre amp.
The Tubalizer has only played for 3 hours, just warmed up, not broken in at all, and has a possibly pos tube. Possibly meaningless as it's too soon to say but...it actually doesn't seem to lack any detail, it is more on the solid presentation end of the spectrum, but still very open, and instruments are spread out well. It has some gravity but is not at all slow or heavy, not at all. You can get inside the music, but it isn't as much of a Lucy In the Skies With Diamonds kind of ride like the MM can be ("atmospheric"). It's more Earthly, but still 3D. Is this a common Octal trait? I need a GOOD 6SL7 tube to see what it is capable of, and several days of break in.
I'll compare the two as I go. Guys, I'll try to give meaningful descriptions/comparisons to aid the audio cause, but you're gonna have to read between the lines as "That's not my area" (as Michael would say).

It is obviously a good, maybe great deal. The hum problem needs to be resolved. Hopefully just a tube.
It may be a great part of ~ $1000 system. Ex: I am using an integrated gainclone ($250 for parts), used Sony 685 cdp ($150) as transport, $350 nos dac, Hawthorne Silver Iris speakers ($325 + $25 wood), and ~ $100 cables, Tubalizer $110. ~ $1300. There's even cheaper components than this that are as good.
So the Tubalizer may end up being in the group of new low cost great gear. Ashok and others will have their own points of view on that soon.

Take care,
Don

[ashok]

Hi everyone,

I finally tried the tubalizer in my system. I introduced it at the output of my CD player.

CDP --> Tubalizer --> Series/Shunt attenuator --> EL84 Amp

The tubalizer is powered by a 12VDC/500mA wall-wart supply.

On the tubalizer is a pot that lets you adjust the operating point of the tube. At one extreme position, I can hear a hum even over the music that is playing. Turning the pot towards the other end will get rid of the hum, but it appears to me that the sound is distorted a little. I wrote to autocostruire about a week ago, and am awaiting their response. Don, did you see this kind of behavior too?

With a little patience, one can find a spot with the pot where there is no distortion and the hum is not noticeable.

How does it sound? I am afraid I am not very good with audio jargon. But it does seem to me that there is very slight loss of detail with the tubalizer in place. I do not know yet if I like it or not. More listening is needed. Apart from that, there does not appear to be any great difference in the sound, with or without the tubalizer. The tubalizer might show its presence more if applied in front of a T-amp. That will be tried in the next few weeks.

Regards,

Ashok

[nodiak]

Ashok, I did find the same behavior when adjusting the bias control, and I settled about 2/3 to the right. Also I burned mine up and they are sending me a new one. The RS wall wart has seperate input tips that can be inserted either neg or pos, of course RS person nor me knew which. First guess was wrong...It goes positive.
I will try a battery next in hopes of eliminating hum. Obviously not an electrician here, maybe it is board components with usa power that are incompatible?
So I liked the sound with my gainclone. It does soften the sound some, but at the same time gives some atmosphere I liked and congealed the music somewhat too. Maybe if you already have tubes in the mix it is less effective. They did seem to develop it for T amps and could work well with them as you say.
If this doesn't work out I may seek a different tube buffer, or a simple octal pre.
Will be good to hear your experience with a T amp, which one?
Don

[ashok]

Don,

The T-amp I bought is the Charlize. I have had it since December '05. I am hoping to put it together in the next few weeks. A single 12V/7.5Ah battery will power both the Monica and Charlize. There should be enough juice to power the tubalizer also. I really hope that the tubalizer works out. My system would then be CDP - Monica - attenuator - tubalizer - Charlize. Very simple.

Ashok

[Wind Chaser]

No speakers?

[ashok]

No speakers?

I have a telepathic connection with my amps   . When that connection does not work, I use Omega TS-1s.

Ashok

[Brad]

Wind Chaser - he said he's trying to keep it simple  

Next, you're going to want him to use cables of some sort to connect everything - and that'll open a whole new can o' worms.....

[BrassEar]

I will try a battery next in hopes of eliminating hum.

Please report back. I would be interested in trying this powered by a large 12V battery and using a decent tube. I have played with various DIY tube stages and when they work they can add just a touch of depth and SET-like vividness.  This could be a bargain solution if you are after this kind of sound.

[kbuzz3]

I know this is slightly off topic(and that i once osted previously on this) but who is going to try their integrated. Seems like the best of both worlds. Id like to but the red wine signature and potential of a channel island integrated
is making me hold back. Of course neither of these options have the tube built in.  I think is a  really ingenious idea, just curious how it sounds.

http://www.autocostruire.com/catalog/product_info.php?cPath=41&products_id=294&osCsid=060f0d3b015b495637563bd385b49267

[nodiak]

Ashok and BrassEar, I am waiting for the replacement tuba. I gathered several different tubes to try and have the battery ready. I did get to use it for a few days before it fried and enjoyed it. It definitely wasn't bad, but I'm not sure the level of improvement it brings. Anyway, I'll report in when things are tubalizing again. The designers told me what parts to replace on this one so at some point I will have it fixed too.
Don

[Luigi]

Hi Guys

My 2c worth on the Tubalizer. I had a stepped attenuator lying around which sounded really very good, and was too expensive to leave doing nothing (it was reviewed in TNT see here: http://www.tnt-audio.com/accessories/stepped_attn_e.html).

So I ordered in a Tubalizer and put the two into an enclosure with the Octal poking out the top. That way everyone knows it's a tube preamp, and it looks pretty cool, despite the cheezy metal box.

Anyway, given the hum problems reported I decided to use a 12v SLA.

Hooked it up for the first time last night, and whoa, this is good. There's more hum than with my Tribute Audio autoformer-based preamp, but even using the 96dB Hempcones, the hum is low enough in the noise floor that it bothers me not.

Havent done direct comparisons yet with the autoformer (which is as good a preamp as I have ever used) but this too is a cracker. Like the Tribute unit, Im happy to play rubbish quality CDs that I had written off as unlistenable with other preamps in the system. So it has that musicality thing going. Briefly, it seems to image brilliantly and is tonally accurate, with the sort of clarity the Tribute offers. Both appear to have the performers there singing and playing in the room just for you.

I had a brief play with the "tuning" screw but it only really sounded right with non-rolled off treble when turned all the way clockwise. I need to check whether the hum is reduced at all other points of the compass, but given it sounds best turned fully clockwise I probably wont worry about this much.

Looking forward to comparing this with my Tribute soon and checking out how it works with other amps. So far just hooked it up to my AKSA 50 Nirvana. Never heard the amp sound so good with these two preamps.

The point of all this? Here is a great buffered passive preamp which costs about half the price of the autoformer-based preamp and gives it a real run for its money.

[nodiak]

Thanks Luigi, good to hear. Possibly the battery will help, but apparently still sum hum.
Hope to have one going again soon.
Please check in about your comparisons, much appreciated.
Don

[BrassEar]

Thanks Luigi, interesting comments.

Does anyone know what the pot does? Does this starve the tube and increase distortion?

At the price, I should probably just break down and buy one. Then wire it up to a regulated 12V supply and also a battery since I have both laying around.

Thought this was interesting, read the last part of the article where it discusses powering a DAC directly with a battery.

http://diyparadise.com/dacs.html

[Luigi]

Hi Brassears

Actually, as it happens, I have one of these, the Monica 2. This has a low voltage output, so will only work in systems with high sensitivity speakers and a reasonable sized power amp, or else you will run out of volume.

Havent really had a good listen to it as yet. It seems however, no better than my Ah Tjoeb CD player, with tubed output stage and upsampler. But it is early days with Monica.

Meantime, am planning listening sessions to determine strengths and weaknesses of Tribute audio autofomer-based preamp and stepped attenuator plus Tubalizer preamp. Planning on doing this with a few others tonight.

Cheers
Luigi

System: Ah Tjoeb CD with upsampler - magnetic/passive preamp - AKSA 50wpc Nirvana - Hempcone speakers in DIY ported cylindrical cabinets

[Luigi]

As promised, last night me and a tubaholic mate got around to comparing the Tribute Audio autoformer preamp with the other "passive" I've slapped together (Acoustic Dimension stepped attenuator plus Tubalizer).

Er, within about a few minutes, we realised there was a winner here. The preamp with the Tubalizer edged out the magnetic volume control, which was a huge surprise given it cost half as much Better clarity, far better staging, improved more real imaging, a more forward presentation. All good. Just as if a tube preamp had been introduced to a solid state system in terms of staging which, of course, it had.

By the by, there is no hum with the Tubalizer when used with a 12v SLA. All the hum we heard previously was power amp generatied. No hum at all with Charlize, a bit with the AKSA50Nirvana, a bit less with another solid state "meta-class A" amp. Interestingly, the AKSA was the best sounding of these three, despite having the most hum. When I say "most hum", this is with 96dB Hempcone speakers and is still only just audible from the listening seat with CD on pause.

And by the by, I was wrong about Monica. I hadn't listened to it much before because I had gain problems with the little Charlize amp. But with the AKSA back in the system there is now sufficient gain and I managed to get good listening levels with Monica (that is to say loud enough to get the Missus to yell at me from the other end of the house). This is a good wee unit, and surpasses the Ah Tjoeb plus upsampler single box player (tubed output stage). As Sam T would have said, there's just more there there. Guess there is something to this NOS thingy afterall.

Luigi

[BrassEar]

Thanks Luigi, I guess I will have to bite on this one and try it. I already have a battery, switch, charger, etc. that I was using for my Monica so it will be just too easy to try this.

Still using the stock EH tubes?

[Luigi]

Hi Brassear and other tubalizer users

Im using the Siemens gold pin ECC88s. Tried some cryoed Bugleboys as well but couldn't justify the expense. Just using the standard Sovtek Octal in the Tubalizer.  

I am now considering trying the Tubalizer with Monica, and will also try it as a replacement for the analogue output stage in my CD player. I also intend giving it a lash with the Tribute volume control, though in theory impedance mismatches should not be such a problem with an autoformer volume control. Or am I misinformed here?

Has anyone else tried using a Tubalizer in any of these applications? I am most impressed with it as an impedance matching device when used in concert with a straight passive preamp. It's a very cool and cost effective device. The only downside is that the octal doesn't glow much on 12v!

Luigi

[Luigi]

Over the weekend I played around with another Tubalizer.

This I nailed to a piece of wood - my DIY skills know no bounds - and I have hooked it up pretty much everywhere in the system.

Someone suggested I try it before the passive preamp(s). So I hooked it up after the Ah Tjoeb CD player, before the passive preamp (a Tribute Audio autoformer). And then after a Monica DAC and before the same preamp.

In both positions the Tubalizer had no effect that I could discern.

But after the passive preamp (in this case the Tribute Audio autoformer) and before the power amp, a quite dramatic difference, all for the positive. In fact, much the same kind of effect as I noticed with the other stepped attenuator- more transparency, improved staging etc.

And this is what I would have expected.

The analogue output section of the CD player is essentially a tube buffer stage anyway. What the passive needs is help driving the cables and power amp, and this is clearly where the buffer stage works a treat.

Having said that, the people who make Tubalizer reckon it can be used INSTEAD of the analogue output stage in a CD player. This I have yet to try.

Has anyone else had any experience with Tubalizer replacing analogue output stage of a CD player??

Luigi