[Freo-1]

Based on feedback from Tom and Jan Plummer, decided to try a second TBI amp in mono.  Since I didn't have a second battery, connected the two TBI amps via the AC power supply.

In short, the sound improved remarkably.  There was a concussive presence and 3D presentation improvement that was not evident with a single amp in stereo.   There was a noticeable improvement in low level detail,  along with better dynamics.   I suspect that since my speakers are 88db/w efficient, the extra power was indeed welcome, and improved the overall performance.  I would think that any speaker setup would benefit from a mono setup. 

I would encourage anyone using a TBI amp setup to audition with a second amp in mono. 
 
 

[rodge827]

I would encourage anyone using a TBI amp setup to audition with a second amp in mono.

Freo-1

I have enjoyed your writings of the MG3 all are very through, even handed, and conclusive. 
I believe I'm next on the tour after it is all tricked out and ready to dazzle  .

I have a couple of questions regarding the quote above:

When you reffer to the MG3 as a mono amp, are you using (2) stereo MG3's, but use only one input per side?

Does or can the MG3 be bridged or reconfigured into a true single channel mono amp?

My speakers (Shelby + Kroll) are a 2.2 set up. The monitors are 86db and bottom out at 100hz with a 6db slope.
A pair of the TBI mono amps would be the way to go in my system.

Chris

[Audioclyde]

I'm very anxious also to learn how to use the amps in mono; I like the TBI enough just on AC pwr that I will buy another if I can use them in true mono for a noticeable improvement.

Thanks for any insight!

Randy

[Freo-1]

Cheers, mates!  Happy to help out.
 
I have each TBI connected to the left channel input.  This is Jan's response to my question regarding mono usage:"

" On your questions below the use of two amplifiers would increase your available power by at least 30% as thermal limiting determines the max power. You would also increase your channel separation to near infinity or at least to that limited by your source equipment. An additional benefit is the ability to adjust the channel levels independently if balance was an issue not addressed elsewhere in the system."
 
Based on the above advice, went ahead and got a second amp.  I figured that if it didn't work out, would simply sell it.  Happily, the improvement was very noticeable.  I would think speakers that are 86/88db/w would benefit a lot form mono usage. Again, the AC source in mono actually sounds better than the battery in stereo.  I will eventually upgrade the power supply section, as the folks at TBI are looking into this. 
 
I do not think the amp can be bridged safely.   
 
 
 
 
 

[rodge827]

Thanks Freo-1

I thought that was the way to use two MG3's as mono's. 

I just sent Tom my mailing address and the amp will go out soon, hope to have it early next week. 

Itching to hear how they will mate with my Dspeaker Antimode Dual Core 2.0 and Shelby + Krolls. 

Chris

[Freo-1]

Thanks Freo-1

I thought that was the way to use two MG3's as mono's. 

I just sent Tom my mailing address and the amp will go out soon, hope to have it early next week. 

Itching to hear how they will mate with my Dspeaker Antimode Dual Core 2.0 and Shelby + Krolls. 

Chris

No worries!  My guess is that you will love it!   

[OzarkTom]

I'm jealous, I guess I need to get me a second one. I still might have to use a battery though, my AC is as bad as you know what.

The tour amp is shipping tomorrow with fresh batteries and the new RCA connector mods. Have fun Chris.

[rodge827]

Thanks Tom will do   

[Mister Pig]

Rex charge up the tour battery and found that it  would charge only to 22V, so it has seen better days. We are still waiting on those two 12V Amazon batteries that I mentioned earlier. The total with shipping was $26.

Speaking of my buddy Rex, I went to visit him over the Labor Day holiday and we experimented with the different set-ups. We thought that the 24V  battery sounded about 5-10% better than the 12V. Now if you are using 4 ohm speakers, the 12v might be better. Since one battery was 12v and the other was 24v, we did not hook two amps up. But we did hook up two amps with the AC power supplies, and to my surprise, that sounded the best. The way I understand on that, it has to do with thermal limiting on the amps. The sound was smoother and more open. I want to try that on my system, but do not hold your breath. My power here is very dirty in the town I live in, and battery will probably win.

I am hoping we can get the tour amps back on the road later this week.

From my experience the amp has a different presentation on the stock power supply versus running on battery. There may be situations where the stock PS is preferred. I did run my PS after an Audio Magic Mini Reference power conditioner, and that may be a contributing factor to the performance I got from it. With that being said, i would love to hear the amp on a linear power supply as well. The point of my post is that there may be instances where the amp shines with the stock PS.

I don't know if I mentioned this previously. But there is a friend I know who has one of these amps, and he has gotten positive results with filling the battery chamber with ESR paper. Apparently the noise floor drops a degree with this option. Just putting that out there for someone to consider.

Regards
Mister Pig

[Freo-1]

From my experience the amp has a different presentation on the stock power supply versus running on battery. There may be situations where the stock PS is preferred. I did run my PS after an Audio Magic Mini Reference power conditioner, and that may be a contributing factor to the performance I got from it. With that being said, i would love to hear the amp on a linear power supply as well. The point of my post is that there may be instances where the amp shines with the stock PS.

I don't know if I mentioned this previously. But there is a friend I know who has one of these amps, and he has gotten positive results with filling the battery chamber with ESR paper. Apparently the noise floor drops a degree with this option. Just putting that out there for someone to consider.

Regards
Mister Pig

Mister Pig, I can also report that the sonic character of the TBI changes significantly when used as two mono amps.  The AC power source seems to work better when it it only pushing one channel vice two channels.  Since my speakers are only 88db/w (albeit a easy load), they really woke up and became alive when a second amp was inserted in mono.  I think it sounds better on AC with mono than a single amp on the battery.   I do have the AC plugged into a line conditioner, which seems to help a bit as well.
 
Jan is working on a power conditioner to work with either battery or AC, so I'm excited to see where this leads.   For now, holding off on getting a second battery setup. 
 
I also think a linear PS would work well, and perhaps even better in a mono setup.

[rikhav]

Anyone compared 2 monos running on AC supply vs 2 monos running on battery

I think the AC supply running through power conditioning is a very important factor for it working well


Quiet a few posts back I had asked the same thing (running AC PS through power conditioning)  and will it work but i got a negative reply

[Freo-1]

Anyone compared 2 monos running on AC supply vs 2 monos running on battery

I think the AC supply running through power conditioning is a very important factor for it working well


Quiet a few posts back I had asked the same thing (running AC PS through power conditioning)  and will it work but i got a negative reply

I think there was a misunderstanding somewhere.  It surely will work, but there still is AC as the power source, filtered through the UPS.  Not the same as directly off a battery.
I don't think anyone has posted yet about mono usage with batteries at 24 volts.  I would think it would be even better than the AC source, although I would think one hits the laws of diminishing returns.

[OzarkTom]

I will try and get two amps and batteies hooked up ASAP.

I found an interesting discussion tonight on Youtube from Harry Pearson at 2009 RMAF about AC interference. Harry says that Enid Lumley fist complained about AC interference 30 years ago in The Absolute Sound and everyone thought she was crazy, maybe she had lived in my home town

Harry also talks about the advantages of batteries.

http://www.youtube.com/watch?v=SA-5fn0Iu8k

[tabrink]

 
Keep in mind there is single conversion and double conversion circuitry in UPS design. Double conversion albeit much more expensive has the battery in the circuit design full time. Remember AC to DC and DC to AC not AC going away and DC coming on line. Double conversion has power conditioning (battery) in series with load!

[JLM]

I've tried battery amp and source, but could hear no advantage (other AC members said the same about the source).  I've heard power abberations, but fully believe its a local phenom.

Seems like we're drifting from the "Giant Killer" concept to 4 components and twice the money with lots of fuss.

BTW, is there still a tour?  Whats the status?

Has the train left the station or ran off the rails?

[OzarkTom]

The tour has resuned with the new Cardas RCA mods and fresh batteries. Chris should receive the amp tomorrow or the next.

[Freo-1]

For those who have or are auditioning the TBI, I would recommend trying it out with a  tube preamp if you have one available, or can get your hands on one.  My good buddy just got through building a Conrad Johnson clone, and asked me if I would try it out for him.  He makes some outstanding amps and preamps , and uses only the highest quality parts.
 
It needs to break in, but I can report that after a few hours of use with the TBI amps, the sound has taken on a more natural sound character.  If I had one minor quibble (and I do mean minor), it was that the Pass Labs X 2.5 with the TBI was almost too analytical.  The CJ clone with the TBI does not sound overly analytical, but still sounds detailed. There is ever so slight less attention called to the detail, and the tonal presentation is just a bit more natural.  I think there is something to the whole tubes/class D combination.
 
I'll post more once the preamp breaks in a bit, and put up a couple of pics of the unit in the Lab circle.  It looks great, and build quality is first rate.

[OzarkTom]

There is a new cable review at Positive Feedback by John Hoffman, and he uses the TBI Millenia as the test amp. Remember, if you are on tour and wanting to compare cables, this little TBI is a great reference tester.

http://www.positive-feedback.com/Issue63/wireworld.htm

[rodge827]

OK I'm sold!

Now I have to go and explain to "she who must be obeyed" that the fantastic best sounding amp that I now own HAS to be replaced!       
Tom I don't know if I should curse you out or buy you dinner?

All kidding aside this little bugger is one very special piece of musical gear.

The first thing I noticed was pitch perfect tonal quality of acoustic instruments, then dynamics kicked in, and lastly the pace and rhythm is so eloquently portrayed. I'm a big fan of acoustic guitar, acoustic jazz, piano, and bass. The tonal quality that this amp has is impeccable. I'm not a very good writer and can't stand the standard cliche audio verbage that is so over used and missplaced. But this dinky little $500.00 battery powered amp has almost forced me to think of words like kills, stomps, slayes, crushes, and out performs amps costing 10 times more! Oops I guess I just did write those things .

I've been listening to live studio, closed mic studio, and live concert recordings and can't get enough how good and intoxicating the sound is. I had only gotten through half of the demo tracks cause I just kept listening to the complete disc and thought why change it this stuff sounds good!

This amp picks up where the Altmann amp leaves off. The Altmann was clean and tonal, but after a while sounded kinda flat in the dynamics area. The MG3  adds that next level in dynamics and dare I say a 3D soundstage. Cassandra Wilson's voice on Robert Johnsons' "Come On In My Kitchen" (Blue light Till Dawn) has a sultry, bluesy, and hot sweaty seductive nature to it. By the time the track ended I swear the humidity and temperature was raised in the room and I was in Mississippi about come on in her kitchen. The MG3 does have the ability to connect and bring the listener emotionally into the music. Very engaging!

About a year ago I sold off most of my old system due to a financial need. The gear was custom built Audio Note Kits Dac and Preamp, as well as a highly modified Antique Sound Labs 300b amp. My speakers were Medallion 2 BLH with Lowther DX4 drivers. I kept my 47 Labs Flatfish transport and battery power supply. My system now consists of the Flatfish, Dspeaker Antimode Dual Core 2.0., MSB Digital Director, Virtual Mode SS Amp, DNM HFTN IC's, DNM Stereo Speaker Wire, and Shelby+Kroll Nano Monitors with matching Woofer Monitors.

As you can see I had a very good SET Full Range Horn system and have a pretty good idea of what the SET Tube sound is. With the MG3 in place I feel ,no... know, that I'm back there in that magical sweet SET domain. The amp connected me to the music and brought out the delicate nuances that can take you deep into an artists soul. I hope to someday pick one (or two for mono use) up and have it be the backbone of my system.           

Tom, sharing this little gem with the AC community is an awesome thing.

I can't thank you enough for including me in your tour,

Chris

 
 

[Freo-1]

Very nice review, Chris.   
 
Don't color it, tell us how you really feel!