XTZ AP-100 Power Amp Review in HiFi Choice

[audiosanctum]

The recently launched XTZ AP-100 Class A Power Amplifier has been reviewed in the October edition of HiFi Choice magazine.

Here are some comments from the reviewer Richard Black:

"Construction is very solid.. which provides screening between input, power supply and two power amp circuit boards."

"It's lively and full-bodied and it can do some lovely subtle things with quiter tracks."

"There is not much around that we can compare this amp to directly, at least not in the way of power amps, but among integrated models it competes with favourites from Creek, Cambridge Audo, Arcam and so on. That it does so, while retaining it's own character - and it's mode-switching feature too - is admirable."

Overall HiFi Choice gvae the AP-100 4 stars of 5.

The Unit retails for just £515.00.

More information regarding the XTZ AP-100 can be viewed by clicking below:

http://www.audiosanctum.co.uk/Power-Amplifiers.html

[Reid Malenfant]

Sorry but i'd be very interested in some more information on this amp that i can't seem to find?

Specs say it'll do 50W RMS in class A into 8ohm, fine so far...Then it goes on to state that it can produce 110W RMS into 8ohm class AB, all well & good.

The thing that i'm not quite understanding though is the mention of 4 transistors per channel. Here are my reasons for wondering how this is done.

With a 50W Class A amp the power supply will need to be at least +/- 30V if not a tad more due to component losses & voltage sag on the PSU capacitors, so lets say +/- 35V to take these into account as we need 20V RMS or if you like 28.28V peak.

Class A at 50W 8ohms requires a 1.25Amp quiescent current & with +/- 35V that will be a dissipation of 87.5W over the 4 transistors or approximately 22W each. That's not too bad.

However unless the amp is switching between two different rails it starts to look a lot worse. At 110W 8ohm you'll need rails of approximately +/- 49V & with the same 1.25A quiescent these 4 transistors will be dissipating 122.5W or nearly 31W per transistor. 29.66V RMS & 41.94V peak.

That's not so good unless some seriously high power transistors are used in the output stage.

So can i ask exactly what transistors are used on the outputs? I'm also assuming that each side of the amp from front to back will basically be heatsink of the large heavily finned variety

Thanks in advance

[audiosanctum]

Hello Mark,

Thank you for the questions.

The output stage uses a sliding bias arrangment to reach 50 watts of class A output without ending up with fried transistors. They are Toshiba 2SC5200/2SA1943 by the way. This way the quiescent current can be kept lower, still not leaving class A mode because of the sliding bias circuit that ensures the bias current never cuts out completely during the opposite half way.

[audiosanctum]

I forgot to add that there are heatsinks on both sides of the case all the way down each side to aid cooling.

[Reid Malenfant]

Many thanks for the reply Is there anywhere in Cambridgeshire that has these amps in stock or am i asking a daft question

I wouldn't mind getting a listen to one in reality

[audiosanctum]

We are the UK exclusive retailer of XTZ products (XTZ has only one retailer per country and cuts out the distributor to keep the price of the products down).

If you would like to demo one we can send our demo unit out to you which you can try for a few weeks. If you like what you hear we will send you a new unit over. All we ask is a deposit of £250.00. If you like the unit we will ship the demo item back, take the balance from you and ship out a new unit. As the total cost is over £500.00 there is free shipping.

If you decide the amp isn't for you then we will ship the demo unit back and refund you the deposit minus shipping costs which would be £45.00.

This demo facility is used by 50% of our customers and i would say 90% of them decide to go for whatever they have demo'ed.

[Reid Malenfant]

Interesting, i quite like this idea

I'm assuming you'll be on the forum for a while & not run away for at least a few months? I need to get a set of speakers together that will run off of a single stereo power amp before i entertain the idea. That shouldn't be too long i'm hoping in which case i'll then get in touch & get something arranged

[audiosanctum]

We will certainly try our best to maintain contact on here. We will keep the forum updated with any reviews or new products so you can contact us through here or send us PM or you can email us on info@audiosanctum.co.uk.

[captain]

Could you tell me if the D-100 integrated Amplifier has balance control.

Thanks

[Alex_UK]

If you would like to demo one we can send our demo unit out to you which you can try for a few weeks. If you like what you hear we will send you a new unit over. All we ask is a deposit of £250.00. If you like the unit we will ship the demo item back, take the balance from you and ship out a new unit. As the total cost is over £500.00 there is free shipping.

If you decide the amp isn't for you then we will ship the demo unit back and refund you the deposit minus shipping costs which would be £45.00.

Also an excellent idea if you are needing to sell an existing amp to part-pay for the new one - should be able to decide if you like it and sell the old one before you need to pay for the new one.