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TCC TC-754 - line-level preamp + MM phono stage

Finally...The T-Preamp!

[T-Preamp front view]
[Italian version]

Product: TCC TC 754 - stereo solid-state preamplifier
Manufacturer: TCC/TEC - USA/China-Taiwan
Approx. price: 79.50$ (in the US) or 92.50$ [ ± 80 € ] (worldwide) - shipping included
Reviewer: Lucio Cadeddu - TNT Italy
Reviewed: December, 2005

The T-Amp-mania has definitely spread all over the World and there's no HiFi Forum without a thread related to this little wonder. The T-Amp has definitely generated NEW interest in affordable HiFi and a huge number of "new" audiophiles has started buying HiFi components for the first time in their life.
Sound-wise there are very few complaints to make, the little wonder still sounds STUNNING one year after our original review was released. From the point of view of the "ease of use" the T-Amp isn't exactly your best choice. One single input, just line-level, isn't what a "man of the street" needs.
Indeed, many customers use more than one Music source (CD, tuner, tape recorder, PC and....turntable) so playing with the T-Amp is nearly impossible without the aid of a preamp. The problem is that HiFi preamps are normally BIG and expensive. Furthermore, many of these no longer offer a phono input for playing vinyl, making an external phono preamp a necessity. All the procedure is definitely too expensive and complicated. Till now.

I've discovered this little gem, a stereo preamp the size of a T-Amp, with 3 line level inputs and (hear hear!) a phono MM input, which can share the very same external power supply with the T-Amp!...all at a cost that won't disappoint you (90$ or 80 € if you prefer). If that's not enough for you, the whole package includes a 12 Volts AC/DC converter, some cables with gold plated terminals, electronic switches, gold plated RCA inputs, a metal black-anodized case and even a stepped volume control!
You don't need to use fancy adapters or perform tweaks: the T-Preamp (as we have decided to call it, from now on) is READY TO GO, just plug and play! It can be used as a minimalist preamp with a traditional power amp or partnered to a T-Amp, once you put the volume of the latter to its maximum. This way you can control the volume via the T-Preamp potentiometer.

Tech specs

[T-Preamp inside view]

The unit is fairly simple: made in China/Taiwan by TCC/TEC it makes use of a fully discrete (!!!) MM phono stage and just a couple of chips (Toshiba TC9208N and TC4013RP) to control inputs and switches. The three line level inputs have zero-gain so you can actually think of it as an almost passive line preamp paired with a phono MM preamp. No tape loop is available and no headphones output either. Leds indicate which input has been selected. The preamp has a kind of internal "memory" that allows input setting retention after switch-off. This way, when you power on again the unit, the last input you were using before switch-off gets selected automatically.
In this price range the market offers just pure and simple MM phono preamps, like the NAD PP-1/2 and the ProJect Phonobox (both reviewed here on TNT-Audio). These make use of opamps and cheap passive components. For the same money the T-Preamp offers a fully passive phono stage (much more expensive to build), 3 line-level inputs (for CD, tuner, tape, DVD etc.) and a stepped volume control. Furthermore, if you take a look at the T-Preamp PCB you'll understand this kind of "order" and quality of manufacturing isn't common in this price range.
The unit is supplied with an external 12 V AC/DC adapter (available both for 110 and 230 Volts) but for best results (see below) I strongly recommend using a GOOD AC/DC adapter, for example the same you use with your T-Amp (3 amperes of max power, AT LEAST, for powering both). The components will survive to voltages up to 15 Volts or so but I recommend not exceeding 13.8, exactly like I suggested for the T-Amp.
The volume pot is a stepped 100 kOhm attenuator with a strange feeling: the knob is very small (the whole unit is extremely small!) and the clicks between one step and the other are uncertain. Anyway, it gets the job done.
Finally, a graph on the top cover illustrates the typical phono RIAA response of the unit.
The unit comes with a 60 days warranty that covers manufacturing defects and is also CE certified.
We've friendly called it T-Preamp though it has nothing to share with Class T amplifiers nor with Sonic Impact or Tripath. It uses absolutely traditional technology.
These are the claimed tech specs:

It has been listened with various partners, two solid-state power amps and a tube power amp, plus the ubiquitous T-Amp. It has been working flawlessly (at 13.8 Volts) for months in my main system.

Price and availability

At the moment, the TCC TC-754 (the so-called T-Preamp) can be bought online only at the manufacturer's website (US only) or here (outside US) or even at Amazon.com. Its cost, at the moment, is 79.50$, including shipping in the US (priority mail) and 93.50$ worldwide with airmail. Payments can be made via Paypal, major credit cards, eCheck or via Amazon.com.
I wouldn't be surprised if it will be modified when demand exceeds availability. It happened the same for the T-Amp, once available at 19.95 $!!!
As far as I know the T-Preamp can't be bought at HiFi or high-tech stores, though this situation may change.
The T-Preamp comes in a "all-inclusive" nice package: interconnects with gold plated terminals, mini-jack to gold plated female RCAs adapter and an AC/DC 12 volts power supply.
The manufacturer offers a vast catalog of other phono preamps, this one reviewed is one of their most expensive components.

Finally....The T-Preamp!

[T-Preamp - rear view]

Here I am, almost one year after the T-Amp review hit the market, with a new impressive HiFi component to be reviewed. Not the usual fancy and exotic stuff, just an unobtrusive minimalist preamp that sets new standards in the quality/price evaluations.
As said, for the same money, we're all used to get extremely entry-level phono preamps. Nothing more than that. Here we have much more: a passive phono stage plus a 3 line-level preamplifier with some nice feature, like electronic switches and memory. The features/price ratio is impressive, indeed.
First of all, it is very quiet: no hum, hiss or noises of any kind. Inputs get selected easily without pops or cracks on the speakers. Human feedback is extremely good: it is easy to use and trouble-free. Let's see if it's ear-friendly too.
First of all, the line-level inputs, then phono.
It is a zero-gain preamp, so it doesn't amplify the signal it receives from the source. Hence, the amount of signal degradation (unavoidable) is closely linked to the signal path and the quality of the stepped potentiometer. The first test I performed (after having listened to it for a long while) was to invite a friend and ask him to express his findings about the sound of my system, keeping the small preamp "hidden" behind the big guys. "Very good" was the answer. You can imagine the surprise after the secret was unveiled! So small? So inexpensive? These were his first comments.
Indeed, the TC-754 is a very nice line-level preamp: perhaps not as refined as high-end gear, certainly harsher and less transparent but still on a par with basic preamps of audiophile fame. Considering the price difference (at least a 5x factor!) the results are stunning. It is pacey, dynamic and lively. Not exactly smooth, especially if you are used to tube preamps but it does get the job done and, for sure, it doesn't become that "bottle-neck" one can imagine, even when inserted in a high end system, where just cables cost 20 times its price.
The system remains listenable and enjoyable: less magic, perhaps, but still very musical. I wonder what it could became with a good ALPS or Palazzo volume pot...
Experienced audiophiles, with very good HiFi components, tend to forget how entry-lvel gear sounds like. Hence, if you have a mega-bucks preamplifier, you tend to compare any other preamp with it. And this is not fair, when dealing with such inexpensive gear. One should always keep in mind how's the sound of the basic stuff. The fact that this unit can sound like a good "entry-level" preamp that costs 5 or 10 times its price is already a miracle, to me. Imagine a car that has a performance comparable to a Ferrari, while costing 5 times less. It would cause a stir all over the World.

Now, in order to evaluate its performance as a pure phono preamp, I've hooked up to my system a NAD PP-1 phono stage, already reviewed for TNT-Audio. The nAD PP-1 is a basic unit, which costs more or less the same (± 100$). The comparison is ethically fair, since even the NAD is built in China.
Oh well, the comparison has been of the no game kind. In every audio parameter the T-Preamp phono stage is so vastly superior that it seems a component which belongs to a totally different price league. The bass is punchier, more extendend and articulated (for example, on "Never as good as the first time" by Sade) while the mids are fuller and possess a far better sense of presence. In the high range the difference is even greater. While the PP-1 fails to reproduce the full harmonic content of the signal, the T-Preamp sounds rich and natural.
As for 3D image, though not exactly wide and deep, it is still better than the two-dimensional diminutive picture of its natural competitor. Overall, it is hard to go back to the "smaller" sound of the PP-1 once you get familiar with the T-Preamp.
Of course, comparing the T-Preamp to, say, a Lehmann Black Cube SE + PWX helps putting things in the right perspective. I'd say that the same difference (order of magnitude, that is) between the NAD PP-1 and the T-Preamp can be found when comparing this one to the Black Cube SE + PWX. Furthermore, the differences between the NAD PP-1 and the (better) Project Phonobox are way smaller, with respect to those I've found between the NAD PP-1 and the T-Preamp.

[T-Preamp + T-Amp combo]
T-Amp (above) & T-Preamp (below). Behind, the latest CD by The Prodigy for a "size" comparison. Not a casual choice :-)

Of course, I've tested the TC 754 with its "natural" partner, i.e. the T-Amp. The combo, thanks to the added features of the preamp and to the still crackingly good sound of the T-Amp, can give many good integrated amplifiers of audiophile fame a good run for their money. Who critized the T-Amp because it was just a chip with a pot now has less excuses. Paired with the T-Preamp the combo can accept any kind of source (even phono!) and hence it becomes a real alternative that should be taken into serious consideration when building any budget-oriented (even portable!) system or a minimalist set-up with very good partners (high sensitivity speakers, for example).

Some advice

First, the obvious (note for T-Amp users): the TC 754 is a preamplifier, so it doesn't add "power" to, say, a T-Amp. It just adds inputs. If you need more than 1 line level input and/or you need to connect a turntable with a MM phono pick-up, you may need this preamp. If you just use a CD player or a PC as single source for your music playback, a T-Amp is sufficient. This preamp doesn't add power or sound quality, just "features". If you wish to use the T-Amp as "power amp", connected and volume-controlled by the TC 754, please set the T-Amp volume to its max setting. When powering on, follow this sequence: first the preamp, then the power amp (for ex. the T-Amp). Viceversa for switching off.

As said, the supplied 3.6 VA AC/DC adapter isn't up to its task. It works, but it represents a serious "bottle-neck" to the performance of the T-Preamp. Use a beefy 12 V (or 13.8 v) 3 amperes external power supply, like the one I suggested to use for the T-Amp (HP 143 or 145 from ZG Italy for example). Any reasonable, regulated 12 V power supply of appropriate power (AT LEAST 3 amperes for powering the pair T-Amp and T-Preamp) will suffice. Feel free to try good, switching power supplies or batteries. A good power supply is strongly needed in order to get the best sonic results. DO NOT JUDGE this unit with its stock AC/DC power adapter.
The correct polarity is clearly indicated: central pole = positive (as in the T-Amp). DO NOT use power supplies which exceed 13.8 volts. Electronic components inside the T-Preamp should survive up to 15 volts. Feel free to use high capacity power supplies (even bigger than 5 amperes, if you are using 1 T-Preamp and 2 T-Amp in biamping mode, for example).
Remember that excessive voltage (read: Volts) can kill a component, excessive "power" reserve (read: Amperes) can't. Quite the contrary: the higher, the better.
As for cables, you don't need adapters of any kind, just "plug and play" the unit to your existing system. The supplied interconnect, though not a complete disaster, should be replaced with anything better of audiophile grade.
The T-Preamp, as well as the T-Amp, is a very small and light unit: big cables may flip it upside down. Use few blobs of blue-tac to glue it to the shelf or use something heavy onto its cover (e.g. a big book).
Some warm-up is necessary, I'd say 15 minutes to say the least. The unit can be left on forever, it doesn't get any warm. When the adapter is connected to the mains, the preamp remains permanently in stand-by mode. After you switch it on a couple of seconds are necessary to get the unit playing.
Before judging its sound, take all the time you need: don't underestimate the unit just because is small and inexpensive (many audiophiles made this very mistake with the T-Amp!). Use the same "care" and patience you'd use with an expensive preamplifier.
Then bear in mind its price, a WOW! will easily follow.


Oh well, a better volume pot might help, indeed! Also, a better power supply (see above) and some tweak to make the cabinet less resonant and prone to vibrate (damping sheets under the top cover, for example) might add some sparkle to the performance of this diminutive preamp. I'd use BrightStar Isonodes as "stock" feet. "Reboxing" isn't strictly necessary, as the cabinet is already good and metallic.
Something that could be done is install the T-Preamp and the T-Amp inside a single sexy cabinet. Consider they use the very same power supply, even the same polarity! Some crazy audiophile might then try to install the small T-Amp board inside the T-Preamp cabinet (there should be enough room). The only problem could be represented by the speakers binding posts, but perhaps these could be placed laterally or on the top cover. Let's the crazy tweaking begin! :-)


Manufacturing and finish. Oh well, it is always tough to criticize something this inexpensive. Anyway, here we go: the stepped volume pot should be replaced with something more precise and possibly without steps: the knob is very small and the pot act as an attenuator: for this reason high output sources may be hard to be finely adjusted: one step below and the listening level is too low, one step above and it gets too loud.
The external 3.6 VA mains adapter is a bottle-neck and it seriously affects sonic performance: it needs to be replaced with something better (read: more powerful), possibly of the switching kind to reduce costs.
The quality of the craftsmanship is good, excellent that of the PCB. Some users may complain because of the absence of a balance control. And, of course, someone may desire a remote control, a phono MC input, a nice headphone output or a tape loop :-)

Sound. Provided you give it a decent power supply, the unit sounds convincing and entertaining and it is very hard to believe this kind of performance can be achieved at such a low price. Anyway, it is NOT a preamp that can rival with serious high-end units. It sounds sometimes cold and dry, for example. And even bass is a bit shy, especially in the first octave.


If the T-Amp bug has already stung you...well, you NEED this T-Preamp to build an impressive pre-power combo that will leave your friends simply speechless. At 130$ (for the T-Preamp + T-Amp combo) it is impossible to buy anything that can come close, even buying second hand.
A real MUST-HAVE for any T-Amper out there. Furthermore, it could be a very clever way to add a good MM stage to your system, even if you don't need the line-level inputs. And, of course, it is something you should seriously consider if you wish to build a secondary system for your kids/wife or holidays house. Considering the money involved you can't go wrong.
Simply exciting!

Read also Geoff Husband's review for more interesting comparisons, here on TNT-Audio.

Copyright © 2005 Lucio Cadeddu - www.tnt-audio.com

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