Initial review: TCC TC-750 phono preamp.

G'day all, well the third and final of my recent overseas online purchases arrived today, a TCC TC-750 phono preamp for moving magnet cartridges and I've just been putting it through its paces and it's not too bad at all, in fact I'm pleasantly surprised.

It arrived complete with a couple of quite high quality looking interconnects and a 'switch mode circuitry' based 12 volt DC plugpack (wallwart). Everything went together very quickly and plugging the plugpack into a 240 VAC output produced a reassuring red glow from the LED on the front panel indicating power on.

There is no power switch and in most situations it is not needed. I don't miss it! The preamp is housed in a small black metal box which feels quite heavy and solid. The back panel has gold plated RCA sockets for the inputs and outputs and are clearly labelled. On the top is a graphic of the RIAA Equalisation curve.

In operation: This is quite interesting as it is very quiet, indicating a very good signal to noise ratio however some slight 'prickle or sizzle' noise is detectable. I attribute this to the supplied switch mode 12 volt DC plugpack (wallwart). I dislike all switch mode based power supplies as they are invariably electrically noisy and also tend to generate considerable broadband radio noise which as an Amateur Radio (Ham Radio) operator I hate! I will make up a fully battery power supply when I can.

On test it's very good. The specifications say 47 k at 220 picofarads which when combined with my low capacitance interconnects, is a good match for my Shure M97xE loaded at 47 k. I played a familiar record and was agreeably surprised at at how well balanced the M97xE sounded with no real treble rolloff. The top cover graphic shows a slight treble lift towards 20 KHz and I wonder if this slight (.5 db) lift was assisting the M97xE. I don't really know, but it sounds fine.

The TC-750 is a fully discrete transistor stage with no op amp circuitry, and it is apparent the discrete transistor circuitry does sound 'different' to op amp based circuitry. One slightly negative thing though, as an inpromptu test I did momentarily fire up my 100 watt Ham Radio transmitter on the 20 metre band (14 Mhz), and a very loud and unpleasant 'screech' was the result from the TC-750.

It was somewhat worse than my usually used phono stage (my DIY ESP P06). Being fully discete transistor based (excellent response at RF frequencies), I would expect possible issues with high level RF breakthrough.

In the end though, to these ears the TC-750 sounds good. I will do some A/B comparisons with my reference DIY ESP P06 phono stage, however at first listen this little TC-750 delivers the goods! :thmbsp: :yes: Regards, Felix aka catman.

Against the ESP P06.

G'day all, well a most interesting comparison. :yes: I compared it against my ESP P06 set for 62 k. This may seem unfair, however it confirms that the TC-750 at 47 k provides a good treble extension with the Shure M97xE. With the ESP P06 at 62 k the treble is more crisp but it is not a massive difference.

Head to head though, the ESP P06 has more overall gain by a couple of db (40 db in 'standard' configuration). In absolute terms the ESP P06 sounds less compressed and more dynamic, however I had anticipated a larger difference, which wasn't the case.

The TC-750 has that easy and slightly 'laidback' sound which seems to be apparent with discrete transistor circuit phono stages as a general sonic characteristic. The next evaluation will be with the AT95E phono cartridge. Stay tuned! Regards, Felix aka catman.

I've had one of these - it's found under a number of different names - and have compared it with the NAD PP1 and the Pro-ject phono box.

I preferred it to the PP1, which did not seem great with dynamics and seemed a little muted. However, the Pro-ject phono box was better than both and showed up both the others in its dynamics, bass and treble extension detail.

My feeling on the TCC and its clones is that they aren't bad for the price, but, to be honest, moving up to the Pro-jects or the Cambridge Audio phono stages lifts the quality markedly for not a dramatic increase in cost. I'd think something like the Pro-ject or Cambridge Audio phono preamps are about the minimum for decent quality, given they're not hugely expensive.

G'day mate, I was quite keen to try it for it's fully discrete transistor circuitry as all of my other DIY phono stages have been op amp based.

It's certainly much better than entry level. It is surprisingly good. :yes: Regards, Felix aka catman.

Also you should make comparison after feeding PS through well regulated linear PS using LM317. It makes lot of difference.

G'day mate, yes I'm going to upgrade the power supply to either a large 12 volt gel cell or a linear power supply. I really hate switch mode power supplies. Regards, Felix aka catman.

Interesting...

I've read your posts about running the M97xE and stock stylus at 62 k. I never had a phono stage with that option, but I also found setting the capacitance around 220pF had a similar result as far as opening up the highs a bit. Seems like the TC-750 is a great budget match for the M97xE.

I did try a TC-750 and added a 100pF / 200pF (probably around the original 220pF with the wiring) capacitance switch because the 220pF made my Audio Technica cart sound too bright. It's a very decent sounding phono preamp for sure, but I still prefer my humble ART DJ II. It did take me quite awhile to choose between the two. The ART has a hint of warmth some may not care for, but I just like it. Perhaps with another cartridge besides the Audio Technica, I'd prefer the TC-750. I did like it a lot and I am holding onto it.

In the end I thought it, and the PP1 for that matter, were the bottleneck in my system. Replaced the lot with a Rega Fono Mini (£50 here at the time) and learnt what a difference a good phono stage can make.

Incidentally, the phono stage in the amp I was then using for the comparison, a Creek 4040, was better than the lot and the equal of the Fono Mini.

By the way, don't get me wrong, I think it's pretty good for what you pay, it's just that a little more gets you something much better.

I'm also hesitant about the power supply upgrade. By the time you've added on the cost of that then you're moving towards the price of units which are the next level up. Something tells me you have plenty in your shed, though, Felix!

Thanks for taking the time for writing your review, Felix!

Thanks Felix, I was interested in what type of circuit these were using.

Any chance of an internal pic?

Nice review. I have the TC-750LC mated with the Shure M97xE. I use a Pioneer timer to switch my unit on/off.

datafone said:

Thanks Felix, I was interested in what type of circuit these were using.

Any chance of an internal pic?

Click to expand...

It's OK, found one on the net

datafone said:

Any chance of an internal pic?

Click to expand...

FWIW



From http://www.vinylengine.com/turntable_forum/viewtopic.php?t=8011

Also https://plus.google.com/photos/115625650536825071322/albums/5459668282627590513?banner=pwa from http://www.audiokarma.org/forums/showthread.php?t=397797

Cheers anyway buddy

That's the shot I found, defiantly room to play with this thing

And with the AT95E!

G'day all, this is very interesting and frankly I'm slightly confiused as I'm not overly sure why this is happening. Anyway the TCC TC-750 works fine with the AT95E except that the 'coolness' that I've often commented upon when mated with my ESP P06 (set at 47 k), simply isn't there with this TCC TC-750.

I suspect, but can't prove that the slightly higher than recommended shunt input capacitance is the reason. While we're on this subject I really have to wonder why Audio Technica recommend the unrealistically low 100 to 200 picofarads input capacitance for the AT95E. Virtually no typical vinyl playback system will have an overall input shunt capacitance of this low value.

The TCC TC-750's default quoted input capacitance value of 220 picofarads is already higher than the recommended shunt input capacitance for the AT95E! In typical cases this will start to roll off the upper treble but other resonance effects at specific 'spot' treble audio frequencies may also occur 'depending'. Rather weird actually. :yes:

However this may actually work out well as some upper treble roll off may 'balance out' the slight bass roll off of the AT95E, giving the 'impression' of 'well balanced' sound and that's exactly the way it sounds on this playback system! Very strange! :scratch2:

In practice though despite these curious 'incorrect' loading aspects it sounds fine! Don't you love the the whole vinyl analog thing? Confusing but endearing. :yes: Regards, Felix aka catman.

Thanks for posting your observations, Felix.

In the end, for my ears and my budget, after reading the many threads on phono pres, my choice will more than likely be the Cambridge 640P or its new inception the 651P. It seems that for the bang to buck ratio, it is widely superior.

Your posts are always interesting.

Sky

G'day mate, thanks for that. it is all rather interesting if somewhat infuriating as it shows that very small and subtle things like capacitance loading can indeed have a marked impact on any cartridges' 'perceived' sound. :yes: That kind of reminds me of something else as well.

Interesting on the prospective phono stage purchases too. Interestingly enough, I have heard a friends' Cambridge 640P on his system and I thought that it sounded good, at least until he plugged in his newly completed DIY ESP P06 phono that positively blew the Cambridge 640P into the weeds. Frankly, I was shocked.
Regards, Felix aka catman.

catman said:

it is all rather interesting if somewhat infuriating as it shows that very small and subtle things like capacitance loading can indeed have a marked impact on any cartridges' 'perceived' sound. :yes: .

Click to expand...

Yes indeed.

Right now I'm enjoying some Miles Davis on a '70s Technics SL-1200 through an ART DJ PRO-II preamp on the living room hifi (@ 47k loading) and I'm not hearing any of the treble roll-off that I hear on the main rig in the man cave. In fact, it sound freakin' great! Must be a capacitance difference... all I know is it WORKS.

I have not directly compared the P-06 to the mod'ed CA-640P but I can say they sound good in their respective systems. The P-06 in particular continues to impress mightily in the experimental system with both a DL-110 HOMC/ Mitz LT-30 loaded to 8.3k and a Digitrac 200 NE/ ReVoX TT loaded to 47k since what-ever happened and it blossomed into a remarkably transparent, clean, and neutral stage.

I just bought a TCC TC-750, just for the fun of it. And yes, it do have that classic transistor sound, but with some harshness to it. The transistors and resistors are okay, but the cheap caps and the ceramics needs replacement. I think it will do a lot for the sound quality.