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    Topping TP60 Class T amp vs. VTA ST-70

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    Bob Latino
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    Topping TP60 Class T amp vs. VTA ST-70

    Post by Bob Latino on Sat Jan 05, 2013 9:26 pm







    Now I am a "dyed in the wool" tube amp user - BUT - last summer my south facing workshop (which is actually a spare bedroom) would get really hot when I played background music using a spare preamp and a custom Dynaco ST-35 tube amp. I decided late in the summer that I would try one of the new T-amps before the summer of 2013 heat came upon us. T-amps are very efficient and give off only a small amount of heat. T-amps are like Class D amps but include some signal processing and have a much higher frequency switch rate and supposedly have noticeably less artifacts in the audible range than Class D amps.

    In checking out the (many times inflated) specs of some T-amps, I settled on the Topping TP60 (which uses a Tripath 2022 chip) because the actual power output specs were in the range of a Dynaco ST-70 (about 35 WPC into 8 ohms). The T-amps, like solid state amps, will put out more power into a 4 ohm load - maybe 60 watts per channel on this amp.

    I've had the amp for about a week now and it is breaking in nicely. The other day I ran it head to head with my Dynaco VTA ST-70 ...

    Some observations in no paricular order ..

    1. The Topping TP60 is fairly hefty at about 11 pounds. It also has an IEC connector rather than a "wal-wart" power pack like some less expensive Class T amps. It also has TWO power transformers - one for each channel ...
    2. This amp generates very little heat. After being on all day (about 12 hours) my infrared thermometer registered from 78 to 81 degrees F from various places on the outer case of this amp.
    3. It has plenty of power for its intended use as a background music amp in my workshop.
    4. It is totally dead quiet. I can't hear anything with my ear on the grille cloth of each speaker and the volume control all the way to the right.
    5. The soundstage is wide but maybe not as deep as the VTA ST-70. Very good placement of instruments within the sound stage but not quite as pinpoint as the VTA ST-70
    6. Low distortion and good detail for a solid state amp.
    7. Very deep and tight bass
    8. The top end is good but not as smooth and detailed as the VTA ST-70
    9. The general sound quality of the amp is warmer than most "solid state" amps but not as warm as most tube amps.
    10. The amp has slightly less gain than the VTA ST-70 and perhaps just a bit less power than the VTA ST-70. The Topping TP60 amp is rated at 27 WPC (from 20 Hz to 20 KHz) at less than .1% distortion. The VTA ST-70 sounded better at higher volume levels
    11. This amp would be a good and relatively inexpensive "bass amp" to biamp with the VTA ST-70 doing the top end. You could use the (Alps) volume to adjust the amount of bass in relation to the amount top end on the ST-70. If your VTA ST-70 also had the optional stepped attenuator, you could probably dial in a perfect match from the top to the bottom of the audio range.

    Bob

    bcinnamon

    Posts : 26
    Join date : 2011-05-07

    Re: Topping TP60 Class T amp vs. VTA ST-70

    Post by bcinnamon on Sun Jan 06, 2013 9:54 pm

    Here's another option, something called the Griffin Twenty (http://online.wsj.com/article/SB10001424127887323820104578213554169792508.html?KEYWORDS=wireless+amplifier).

    Basically a small Class D amp, 20 watts/side, designed to be connected to an Airport Express -- good if you just want to run some old speakers remotely. Only $99.

    Will try it if I can find my old Advent speakers. In the mean time, I'm delighted with the Airport Express as a pre-amp connected to my ST-120.

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Topping TP60 Class T amp vs. VTA ST-70

    Post by Bob Latino on Fri Jan 11, 2013 3:32 pm



    An update to this post. I bought a power meter off Ebay and connected the meter between the Topping TP60 and the outlet it was plugged into to measure the amp's power usage. At idle it consumed just 9.1 watts. When I turned the volume up to a normal playing level the meter still read below 10 watts. If I really cranked it up pretty loud, the meter still read below 15 watts. Compare that to a Dynaco ST-70 which uses about 170 watts at idle and this little amp is about 18 times more efficient than the ST-70. There are reports online of some of the lower powered T amps using less than 3 watts at idle. That's less power than some night lights use ...

    Bob

    peterh

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    Location : gothenburg, sweden

    Re: Topping TP60 Class T amp vs. VTA ST-70

    Post by peterh on Fri Jan 11, 2013 3:37 pm

    Bob Latino wrote:

    An update to this post. I bought a power meter off Ebay and connected the meter between the Topping TP60 and the outlet it was plugged into to measure the amp's power usage. At idle it consumed just 9.1 watts. When I turned the volume up to a normal playing level the meter still read below 10 watts. If I really cranked it up pretty loud, the meter still read below 15 watts. Compare that to a Dynaco ST-70 which uses about 170 watts at idle and this little amp is about 18 times more efficient than the ST-70. There are reports online of some of the lower powered T amps using less than 3 watts at idle. That's less power than some night lights use ...

    Bob
    Bob, are you proposing that we replace out vta-70 ?? What do you offer as trade-in ?

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Topping TP60 Class T amp vs. VTA ST-70

    Post by Bob Latino on Fri Jan 11, 2013 3:45 pm

    No ... Not by any means .. These class T amps are good and very efficient amps for background music and non critical listening. In other words, they have a place in the audio world and possibly in time MAY equal the overall sound quality of tube amps. I play FLAC files off my computer in my workshop while I am working. It's just being used for background music and it is plenty good enough for that ...

    Bob

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