The Stax Thread III

[SemiAudiophile]

I wonder if Toppings own P50 power supply is compatible or would make any difference?

https://apos.audio/collections/brand-spotlight-topping/products/topping-p50-linear-power-supply

 

[ColSaulTigh]

for those that don't already know, the topping amp is highly similar to the koss amp. opamp front end driving stacked transistors. low power class AB.
good deal for a cheap amp with a stax jack. no way to get those distortion numbers without oodles of open loop gain and lots of feedback.

So you're saying I should get rid of my @kevin gilmore Grounded Grid and replace it with this???

 

[alota]

So you're saying I should get rid of my @kevin gilmore Grounded Grid and replace it with this???

i don´t think so LOL

 

[HifiXMen]

some sources said that topping electrostatic amp were opamp feeding step-up transformers. The official website does not specify the frequency of its maximum output. and we all know that when driving capacitive loads, the performance of most electrostatic amplifiers is suffered from the current limit of VAS at high frequency and very high voltage swing. so I very much hope that there will be more detailed test results from third party to allow those xtreme performance estat enthusiasts to evaluate the design.

 

[kevin gilmore]

srm212,252 etc are 6 volts 1 amp. So 6 watts
koss is 9 volts 1 amp. So 9 watts.
topping is 15 volts 1 amp. So 15 watts
.............
carbon cc is 125 watts
T2 is 225 watts
megatronxxl is 325 watts

no way an opamp driving transformers is going to be able to do .0008% thd

amir (incorrectly) measured koss at .01%
i (correctly) measured koss at .005% which is the limit of my equipment.
(i'm waiting on the new quantasylum qa404)

i do have a problem with the quoted noise figures. Likely they are measured with the attenuator in place.
That is clearly not correct.

 

[ardilla]

Would an upgraded external PSU make a difference in power output /mA on the topping EHA5?

Like the Sbooster 15V dc PSU for instance?

 

[HifiXMen]

srm212,252 etc are 6 volts 1 amp. So 6 watts
koss is 9 volts 1 amp. So 9 watts.
topping is 15 volts 1 amp. So 15 watts
.............
carbon cc is 125 watts
T2 is 225 watts
megatronxxl is 325 watts

no way an opamp driving transformers is going to be able to do .0008% thd

amir (incorrectly) measured koss at .01%
i (correctly) measured koss at .005% which is the limit of my equipment.
(i'm waiting on the new quantasylum qa404)

i do have a problem with the quoted noise figures. Likely they are measured with the attenuator in place.
That is clearly not correct.

From topping's previous amplifier products, the EHA5 normal amplifier section is likely to be a composite amplifier, just like the amplifiers of jds atom and benchmark things. The common practice is to combine a precision opamp1 with a higher idle current opamp2 which has a specified closed-loop gain. opamp2 is placed inside the feedback loop of opamp1, which is the "feed forward technology" claimed by some manufacturers. In fact, it introduces a huge amount of feedback, the distortion test is usually lower than what the manufacturer's specs , but I don't know whether it can drive the transformer to output such low distortion though...never tried before

 

[Chefguru]

srm212,252 etc are 6 volts 1 amp. So 6 watts
koss is 9 volts 1 amp. So 9 watts.
topping is 15 volts 1 amp. So 15 watts
.............
carbon cc is 125 watts
T2 is 225 watts
megatronxxl is 325 watts

no way an opamp driving transformers is going to be able to do .0008% thd

amir (incorrectly) measured koss at .01%
i (correctly) measured koss at .005% which is the limit of my equipment.
(i'm waiting on the new quantasylum qa404)

i do have a problem with the quoted noise figures. Likely they are measured with the attenuator in place.
That is clearly not correct.

Megatron xxl ? Please tell us more …

 

[ufospls2]

Megatron xxl ? Please tell us more …

https://www.head-fi.org/threads/hea...-300b-tube-amps.962932/page-144#post-17475404

 

[Chefguru]

https://www.head-fi.org/threads/hea...-300b-tube-amps.962932/page-144#post-17475404

Ah I see. @kevin gilmore this is a good prank.
I will hold out for the megatronXXXXXXXXXXL^2 where the tubes only last 1 listening session.

 

[kevin gilmore]

nope, not a prank. will post much bigger picture later.

evidently confirmed elsewhere, the topping is the a90d circuit driving transformers.

 

[John Buchanan]

So strange there no SR-2 or the mighty DMA-X2 600watt mono block power amp. Pretty much 2 of the most rarest Stax item I likely will never own.

Didn't see the SRM Monitor either.

 

[alota]

nope, not a prank. will post much bigger picture later.

evidently confirmed elsewhere, the topping is the a90d circuit driving transformers.

just for curiosity: why 8 300b to drive an headphone?

 

[dynavit]

just for curiosity: why 8 300b to drive an headphone?

That's the same with speakers: Add one bass-driver to each side and you can double the price.

 

[kevin gilmore]

each of the 4 channels gets a current source. no different than the original megatron.
very simple circuit.