Teacs for $100 available

lonewolfny42 · « **Reply #60 on:** 9 Jun 2005, 03:03 am »

Quote from: mcgsxr

http://www.audiocircle.com/index.php?topic=11728&highlight=teac is probably what lcrim is talking about... lots of great ideas for DIY in here, and in the end, Vinnie's DC mods are providing lots of folks with a powerful little toy!

Have fun fellow Teac explorers!

Thats it....déjà vu , once again. During that run, the focus was on the JVC models....ES-1, with the Teac getting some good press. I purchased a JVC...didn't knock me out....

Chris[/list:u]

brj · « **Reply #61 on:** 9 Jun 2005, 03:44 am »

Quote from: Dmason

BUT, with the Phat AuriCaps and battery power, even completely UN-broken in, it has the grunt and crunch capabilities of something along the lines of a Bryston 3BST. In other words, the TA2050 done this way completely throws out the book on what "30 watts" means.

Is this a comment on current delivery, or some other aspect of the amp?

If we are talking current draw, then this should be a measurable property of the amps, and we could actually tell if the battery powered, 2 channel version of the 3x30W/6 Ohm Teac A-L700P can supply the same current as the 2x120W/8 Ohm Bryston 3B-ST over some given period of time.

I'm not a EE, but if I recall correctly...

For single phase AC current: Amps = Watts/(Volts * Power Factor)
For DC current: Amps = Watts/Volts

Does the modded Teac convert back to AC, or stay DC? Does it bump the voltage out of the battery back to 120V?

The other missing variable is the power factor of the Bryston. The kVa rating of the transformers might get us part way there, but I suspect that any capacitors in the path will alter this answer anyway.

Of course, we are really looking at current draw as specified over a given time, and the equations I stated above are not integrals or functions of time in any way. This is actually kind of an interesting tangent - can anyone shed any light on this?

doug s. · « **Reply #62 on:** 9 Jun 2005, 12:26 pm »

i recall reading somewhere that a stock sharp sd-ex111 was a bit more refined than the teac. vinnie - any comments about the sounds of these two amps after mods?

thanks,

doug s.

Dmason · « **Reply #63 on:** 9 Jun 2005, 02:22 pm »

"Is this a comment on current delivery, or some other aspect of the amp?"

This was more like a casual observation of some other aspect of the amp.

The Musical One.

The Teac has bass weight and driver control which completely belies its output capabilities, to the extent that it has forced me to discard any notions I had referenced by way of its rated 30 wpc output. In other words, it doesnt behave like any 30 watt amp I have ever been around.

I have been using it with the extraordinary MLTL designed by GM, (Greg Monfort, thanks again GM) but this one uses the Jordan JX92S with the Aurum Cantus ribbon, designed by Dr Jim Griffin. (thanks Jim) The amount of bass GM milks out of this design is what makes it the new legend it is. The amount of bass the Teac milks out of the Jordan is completely at odds with its size, 92mm cone diameter/30wpc amp. This is not an efficient speaker by any means, at about 85db, and the Teac is powerful enough to completely take charge, and serve up some wonderful dynamics. which yes, would allude to some pretty damn serious current capabilities.

In ordering the Teac, I had hoped it would be minimally capable of powering the MLTL acceptably, given its 30 watts. 100 or more would have been what I estimated to be required. Wrong

It makes the rated "100wpc" JVC ES-1 sound anemic by comparison, AND, now the JVC has been rendered unacceptable, both sonically, and in its ability to control the Jordan/AC combo.

Vinnie R. · « **Reply #64 on:** 9 Jun 2005, 03:13 pm »

Quote from: doug s.

i recall reading somewhere that a stock sharp sd-ex111 was a bit more refined than the teac. vinnie - any comments about the sounds of these two amps after mods?

thanks,

doug s.

Hi Doug,

After mods, the Teac does pretty much everything better than the modded SD-EX111:

--better speed, attack, control, dynamics, midrange purity, more extened top end, absense of background noise, you name it!

I'm listening Jacqui Naylor's "Shelter" CD using the battery cdp feeding the Puri-T and a freshly modded Teac as I write this, and the amount of control it has over my Super 3's is amazing...the sound is super fast and exciting, and the bass has a nice amount of weight and body to it (yes, with the 4" Fostex drivers!).

Once I get the time, I will mod my own Teac, which is new in the box and waiting for me

miklorsmith · « **Reply #65 on:** 9 Jun 2005, 04:02 pm »

I'm glad to hear these things, as the stock unit sounds like about a $100 amp. Of course, this is without any time on it and plugged into an old, crappy CDP (break-in special), but man, it's nothing like the amp that preceded it.

On the good side, AC power is GREAT for breaking things in! Maybe Vino should include an AC bypass specifically for breaking in the ornery chips and caps.

nodiak · « **Reply #66 on:** 9 Jun 2005, 06:09 pm »

Dmason, GM shared with me a mltl design for the 12" bass drivers I use. I need to get them built. We were both on a thread somewhere and I asked for someone to run the numbers for me. He offered, I didn't know who he was at the time. Cool. It isn't anything he tested and refined, but should be an improvement over the sealed cabs they're in now. Also, it is a way to get quality bass with out needing $everal drivers for IB, and not cutting into walls. anyway, I'll get to it asap. Wonder how the Teac will drive these bass drivers...Don

brj · « **Reply #67 on:** 9 Jun 2005, 06:09 pm »

Quote from: Dmason

This was more like a casual observation of some other aspect of the amp.

The Musical One.

The Teac has bass weight and driver control which completely belies its output capabilities, to the extent that it has forced me to discard any notions I had referenced by way of its rated 30 wpc output. In other words, it doesnt behave like any 30 watt amp I have ever been around.

I haven't heard the Teac, so I don't have my own reference regarding the more subjective aspects of its sound, i.e. how "musical" is might be. I take you at your word that the Teac is impressively musical.

Based on what I've seen in the past, however, I tend to interpret any comments regarding "bass weight and driver control" to be a reflection of an amp's ability to deliver large amounts of instantaneous current. This is a measurable property and one that I happened to find interesting, because I've never seen a current delivery comparison between a battery (DC) powered amp and a solid state (AC) driven amp. I was hoping that someone more educated than I in the ways of EE might have some informative comments.

Dmason · « **Reply #68 on:** 9 Jun 2005, 06:36 pm »

brj

I agree with you that it is an interesting comparo, but because the hotrodded Teac is so new, I thought it would be helpful, on behalf of the readers, to stick with anecdotes, at least for the moment. I agree that a technical insight could be very helpful.

I think batteries are a near ideal current delivery means, and I am reminded of it every time I start my car, or better yet, my bike. The battery in my bike is about the same size as one of two batteries inside the T-Eac... That would be the most graphic example of battery-borne current delivery [cranking power=bass weight] I can think of. Beyond that, the Teac batTery amp delivers VERY similar bass impact and weight to the Bryston 3BST, an amp with which I am very familiar. And Brystons are bass masters.

Perhaps we can get Vinnie to provide a lay explanation of some of this. He is an electrical engineer.

Vinnie R. · « **Reply #69 on:** 9 Jun 2005, 07:09 pm »

Quote from: Dmason

Perhaps we can get Vinnie to provide a lay explanation of some of this. He is an electrical engineer.

All,

IMO, not all batteries are a good match for power amps. However, Lead Acid batteries have very low internal series resistance and can provide high current. Dmason's example of a car starter is a very good one. You need a lot of current to pass through the starter to generate the torque to crank an engine, and not all types of 12V batteries can make this happen.

That said, my take on Dmason's comments about about the battery Teac having the bass weight similar to a Bryston 3BST also has a lot to do with the fact that he is using high sensitivity, single driver, crossoverless speakers, which are a very good match. If you were to power such speakers with a Bryston, I doubt you'd ever come close to needing the large amout of power that it can provide. I read Dmason's comments as comments about how the Teac sounds like driving his speakers, not how it measures compared to a muscle amp like a high power Bryston. I'm very confident that the Bryston can out-muscle the Teac no matter what size battery I put in there, as the Tripath chip has its power limitations. But when you throw in high-efficiency speakers into the mix, you'd be surprised how much muscle a clean 30-watts can give you.

I clearly remember the 6-watt Lotus amp powering the Omega Hemp speakers at the Montreal show...some people thought we were full of $hit when we told them that the amp was a 6-watt battery amp. We had a demo CD from Triangle Speakers, and one of the tracks was called something like "the garage door test," where the demonstrator was talking behind a metal garage door, and then suddenly banged away at it....quite a few people jumped out of their chairs with that one!

These were lightning-fast transients that the high powered (and much higher-priced) tubed monoblock amps in that room couldn't touch when playing the same track.

Also, the Tripath chips have a really strong grip on speakers (lots of control, speed, and punch). Combine that with the fact that I increase the power supply rail capacitance with low ESR caps, and wire them directly to the power pins of the TK2050. This provides a very short and sweet path between the capacitor's storage of charge and the Tripath chip, which means low ESR and ESL. Still, I can take measurements all day long, but if the modifications don't sound good to me, then they don't mean a thing to me. I prefer this thread not become a technical debate about battery power vs AC power vs. Class-T vs. other amp topologies, etc.

Regards,

Paul_Bui · « **Reply #70 on:** 9 Jun 2005, 08:22 pm »

Yep, I totally agree. Why not let Vinnie do what he does best: mod the Tripath boards and other good stuff such as DAC and transport and make them perform their best, even though he no doubt is quite capable of tech-talking. After all, it's achieving the good sounds - the ultimate goal - that brings us here. For those who have not heard it but wanted to find out, take advantage of the 30 day money back offer. It's that simple.

Owning a FirstWatt F1 amp, a pair of very good sounding minimalist tube monoblocks, and a Shunyata Hydra power conditioner, I could probably have ignored the buzz about Clari-T, feeling that my existing gear should be superior, that technically and theorically the modded Tripath should not be serious thus deserving any audiophile merit. How wrong could I have been if I didn't give it a try?

brj · « **Reply #71 on:** 10 Jun 2005, 12:07 am »

Thanks for the response, Vinnie!

Quote from: Vinnie

I prefer this thread not become a technical debate about battery power vs AC power vs. Class-T vs. other amp topologies, etc.

Through reading and logic, I reduced a perceived audio characteristic down to what I felt was an interesting question: How do the current delivering capabilities of a battery powered amp differ from a traditional solid state (i.e. torroids and capacitors) amp and why. I wasn't looking for a "debate" - connoting argument - and I did not declare that any one product or approach was better than any other. I was looking to learn.

If something sounds better to me, I can accept that for the purposes of enjoying my music. However, I enjoy the "how" and "why" that accompanies virtually everything around me, including the products of science, engineering and technology. You indicated that the use of high-efficency speakers was probably the key to interpreting Dmason's comments regarding driver grip and control, and that makes a great deal of sense to me.

I'm still interested in the learning more regarding the current draw differences between battery amps and SS amps, however. My question originated due to comments posted in this forum, but I have no problems posting a similar question elsewhere if further discussion here makes people uncomfortable.

Thanks for your comments.

Vinnie R. · « **Reply #72 on:** 10 Jun 2005, 02:08 am »

Quote from: brj

I did not declare that any one product or approach was better than any other. I was looking to learn.

I'm still interested in the learning more regarding the current draw differences between battery amps and SS amps, however. My question originated due to comments posted in this forum, but I have no problems posting a similar question elsewhere if further discussion here makes people uncomfortable.
...

Hi brj,

Sorry, I did not mean to cut you off or stop the learning process... I just wasn't sure where this thread was going.

Let's continue:

What do you mean when you say "learning more regarding the current draw differences between battery amps and SS amps?" The current draw on an amplifiers power supply depends on the speaker used ("the load")and the volume level desired. An amplifier is going to have to produce X amount of current (power) to drive the speaker. This power comes from the amplier's power supply, which has a limit on how much power it can provide (RMS and peak). One cannot simply state that battery power or an AC-DC power supply can provide more power than the other...it depends on the design.

There also is a point where having more than a certain amount of power is useless because of the amplifiers design limitation. Once you go past the max power rating of the amplifier, you will get distortion. Sure, the power supply might be able to give the amplifier circuit more juice, but the amp circuit can only handle so much, and that's it. The amplifier's designer need to determine what sized power supply is required for the application. Going above and beyond what is required to operate optimally "within spec" is fine, but adds unnecessary cost.

I like the SLA approach for lower-powerd amps because it is MUCH more simple and cost effective to achieve clean power. Once you start getting into the higher powered amps, the voltage rails become larger and battery power becomes more cumbersome to deal with. My point before is that if you are using high efficiency speakers, you don't need a high power amp.

In therory, an 87dB speaker pushed by a 200 watt amp will play like a 90dB speaker pushed by a 100 watt amp, which will play like a 93dB speaker pushed by a 50 watt amp, which will play like a 96dB speaker pushed by a 25 watt amp (insert Red Wine Teac in this area

), which will play like a 99dB speaker pushed by a 12.5 watt amp, which will play like a 102dB speaker pushed by a...Clari-T!

Again, I cannot state one approach is better than the other, but I can state that I like one approach better than the other, as can everyone.

Regards,

brj · « **Reply #73 on:** 10 Jun 2005, 07:52 am »

Quote from: Vinnie R.

Sorry, I did not mean to cut you off or stop the learning process... I just wasn't sure where this thread was going.

I understand - who would ever think that things might get out of hand on an audio forum?

No problem at all, Vinnie!

Quote from: Vinnie R.

What do you mean when you say "learning more regarding the current draw differences between battery amps and SS amps?" The current draw on an amplifiers power supply depends on the speaker used ("the load")and the volume level desired. An amplifier is going to have to produce X amount of current (power) to drive the speaker. This power comes from the amplier's power supply, which has a limit on how much power it can provide (RMS and peak).

Ok, so the first thing is the realization that most speakers are only occasionly going to draw really significants amounts of power (RMS vs. peak). I.e. We usually care more about the proverbial "first watt" and his friends for RMS loads. The lower the speaker sensitivity (for a given nominal impedance), the more friends that first watt needs. The lower the impedance of the speaker (for a given sensitivity), the more friends that first watt needs. If the amp can meet the peak power requirement, regardless of base technology, then anything else is overkill, right? So do people desire "overhead" in their amps because they simply under-estimate their peak load, or are we back to some current related characteristic that might differ between a battery and SS amp?

Quote from: Vinnie

I like the SLA approach for lower-powerd amps because it is MUCH more simple and cost effective to achieve clean power. Once you start getting into the higher powered amps, the voltage rails become larger and battery power becomes more cumbersome to deal with. My point before is that if you are using high efficiency speakers, you don't need a high power amp.

I think there are two components to what I'm trying to flesh out... how much power is available, and how fast can you deliver it. "power" (watts) is energy per unit time. My understanding of a SS amp is that the torroid provides the bulk of the energy storage while intermediate banks of capacitors provide smaller amounts but faster sources of energy. The simpler battery based system doesn't have these multiple stages of energy storage (to my knowledge). So, raw power availability aside, how fast does an SLA battery delivery energy compared to a torroid/cap system? Presumably, any battery based system will offer far more energy storage in the battery than virtually any capacitor bank in a solid state amp, so if the battery offers its current up at speeds similar to that of the capacitor bank, then this may be part of the answer.

Part of the problem is that I know that there are really integrals with respect to time behind some of this, and I'm not up to speed yet!

Hmmmm... related question... if your power source is a battery, how does that affect your clipping behavior compared to the SS option?

Ok, it is way too late in the evening (morning), and I'm not expressing myself as clearly as I usually do, so I'll take another crack at clarifying my questions tomorrow after some sleep and some more background reading. I think I need to hit "damping factor" as well....

Thanks for your thoughts and explanations so far, Vinnie! (And by all means, split this conversation out to a separate thread if you like.)

dwk · « **Reply #74 on:** 10 Jun 2005, 02:41 pm »

Quote from: brj

I think there are two components to what I'm trying to flesh out... how much power is available, and how fast can you deliver it. "power" (watts) is energy per unit time. My understanding of a SS amp is that the torroid provides the bulk of the energy storage while intermediate banks of capacitors provide smaller amounts but faster sources of energy. The simpler battery based system doesn't have these multiple stages of energy storage (to my knowledge). .

brj - I think you're overthinking this. Conventional power supplies or battery power are simply a means to an end - they aren't inherently right or wrong.

To a first order of accuracy, the bulk charactistic that matters in a power supply is impedance - ultimately this is what determines the current delivery characteristics of the supply. As previously covered, batteries have very low impedance at low frequencies - big SLA batteries are 2-3 milliohms or less which is why they can dump hundreds of amps into a short circuit (or an auto starter). Smaller batteries are higher, but still typically under 10milliohms. The impedance of a battery tends to rise with frequency, but since there is always a parallel capacitor bank of some sort, that doesn't matter much. Above maybe ~1kHz, the cap impedance will become significant if not dominant.

When comparing to a conventional supply, things are complicated by the diodes. The xformer will generally have low impedance (although higher L than a battery, and almost certainly much higher R due to the length of wire in the windings), but it's effectively 'out of the circuit' when the diodes are reversed biased and hence not conducting (ie most of the duration of a single power cycle). The capacitor bank plays a much larger role here, being relied on at low freqs more so than in a battery supply. Now, in a *regulated* supply, the transformer (mostly) goes away and is replaced by an active element, where it's much easier to get very low impedances. Very few power amps use regulated supplies, as it's expensive and inefficient for high current demands.

So, the upshot is that battery power is just a very simple, relatively cheap way to get a power supply that has very low impedance across it's operating range. Low-powered digital amps are about the only things that can run off batteries without major headaches, so why not take advantage of it?

doggie · « **Reply #75 on:** 11 Jun 2005, 02:41 am »

Hi Vinnie,

Does your battery power supply replace the entire stock power supply so that there is no AC going to the chassis, eliminating the power cord, or do the batteries just replace the +28V supply?

Thanks,

Paul

Vinnie R. · « **Reply #76 on:** 11 Jun 2005, 04:04 am »

Quote from: doggie

Hi Vinnie,

Does your battery power supply replace the entire stock power supply so that there is no AC going to the chassis, eliminating the power cord, or do the batteries just replace the +28V supply?

Thanks,

Paul

Hi Paul,

Yes, the entire stock supply is removed and everything is running on SLA battery power.

Regards,

lonewolfny42 · « **Reply #77 on:** 2 Aug 2005, 03:44 pm »

Hello Vinnie,

Thanks....Chris[/list:u]

Vinnie R. · « **Reply #78 on:** 2 Aug 2005, 03:52 pm »

Quote from: lonewolfny42

Hello Vinnie,
Got a question for you. On the R.W. website, concerning the Teac, photo shows the on/off charger switch on the front of the unit.[/list:u]
At the Rave, got to see and hear the R.W.Teac, and the switch was now on the back of the Teac. [/list:u]
Does it make a difference where you put it ? The front location would be easier.....well, in my case. So I was wondering.... [/list:u]
Thanks....Chris[/list:u]

Hi Chris,

Good question, and it is mainly a matter of appearance. I think it looks better on the back, and is still very easy to reach over and flip the switch up or down (the Teac isn't that big). Also, the power lines are a little shorter when the switch is on the back...but I don't think it makes much difference.

I'd be happy to put it on either the front or back, but not the bottom!

Cheers!

lonewolfny42 · « **Reply #79 on:** 2 Aug 2005, 04:03 pm »

Vinnie :

Quote

I'd be happy to put it on either the front or back, but not the bottom!

[/list:u]Well...if you added two more switches to the bottom (three in total)...the Teac would then be spiked....

[/list:u]Chris