An externally hosted image should be here but it was not working when we last tested it.
Today I bought two ProJet Power Modules to verify specifications from this advertisment and make stereo power amp later. I hope they'll sound as good as they look. I intend to put them in metal case of the old Technics power amplifier with big VU meters. But first I'll perform measurements with some spare power supply on big heatsink 😀
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
As I promised the testing session has started with 140V rail to rail voltage and clipping was just 3V under supply voltage. The amp module is very stable and has controled, bright sound at powering on. The IC is running at 55°C and the quiescent current is app. 100mA through each power transistor 20 minutes after power is turned on. The sound at that point stays the same only that is much more warm and pleasant. 😀
There is also opened Technics power amp case where the ProJet modules will be installed after more test procedures.
Report follows soon.
Hi,
100mA bias through each output transistor means half an amp of total bias current.
That should avoid crossover distortion at low level listening. 🙂
But 140Vdc * 0.5A = a lot of heat to dissipate from each channel.
Your heatsinks look too small or they will result in a very high Tc, resulting in a much lower SOAR.
100mA bias through each output transistor means half an amp of total bias current.
That should avoid crossover distortion at low level listening. 🙂
But 140Vdc * 0.5A = a lot of heat to dissipate from each channel.
Your heatsinks look too small or they will result in a very high Tc, resulting in a much lower SOAR.
I still don't get it... you want THX levels which as far as I can see is specified in db not Watts... get more efficient speakers then.
Even some creative labs PC speakers are THX certified... i.e. can reach the db levels (is it 105db?), and those are realitvely small and not all that powerfully amplified...
Even some creative labs PC speakers are THX certified... i.e. can reach the db levels (is it 105db?), and those are realitvely small and not all that powerfully amplified...
AndrewT said:
AndrewT, please read carefully my post in which I said: I'll perform test measurements on spare heatsink left from some other project. This heatsink and power supply unit is used only for testing and sound check purposes. For real instalation I'll use big heatsinks with longitudinal fan starting at 70°C for each channel, all built in a big Technics metal case. It will be dual mono configuration with common mains plug and power-on switch only.There are four output power transistors pro rail, not five, delivering together 0,4A quiescent current, that means 56W idle power dissipation per one module and that will be manageable with the cooling I described. Be very precise by pointing out some facts because you may mislead some less experienced reader.
Nordic said:
Dear Nordic I'm shure that there is a reason for strong amplifiers existing in an audio world. Please check the specifications of let say Musical Fidelity kW550, kW750, Krell FBI, Accuphase P-8000, P-7100, Burmester, MBL, Plinius, Bryston, etc. Did you hear sometimes the amp with almost infinite dynamic and headroom nature like amps I count? Only than you'll now what I'm talking about and why the enormous power or better said supply voltage level is desired.
All that big amps are not produced for unbearable loud listening but for dynamics reasons. Period. 😀
Hi Lazy,
looks like I am mistaken.
I thought post21 was telling me that you intended fitting that 5pair output stage with the sink shown into the redundant case.
On that basis, I gave advice.
But you obviously have other plans. Maybe they were stated in an earlier post.
No, I was not trying, inadvertently or otherwise, to mislead you or others, indeed the opposite.
looks like I am mistaken.
I thought post21 was telling me that you intended fitting that 5pair output stage with the sink shown into the redundant case.
On that basis, I gave advice.
But you obviously have other plans. Maybe they were stated in an earlier post.
No, I was not trying, inadvertently or otherwise, to mislead you or others, indeed the opposite.
OK, it looks it was misunderstanding. 
First implementation of the two ProJet Power Modules into Technics case will be like makeing prototype in donor case. This two channel stuff-story is for prolonged testing purposes only.
My real intention is to make multichannel amp for home cinema with eight mono channels at the end. 😉
First implementation of the two ProJet Power Modules into Technics case will be like makeing prototype in donor case. This two channel stuff-story is for prolonged testing purposes only.My real intention is to make multichannel amp for home cinema with eight mono channels at the end. 😉
Anything new? Is it finished?
Sorry, just found this thread and I agree that an amp with plenty of dynamic headroom can sound very good - I do particularly like the MF KW500, KW550 and KW750. I haven't heard too many other amps with serious power except for a few Pass Labs (X350 and X600) both of which are stunning, but then Nelson has a few patent tricks up his sleeve!
Anyway, is it finished and how does it sound?
Sorry, just found this thread and I agree that an amp with plenty of dynamic headroom can sound very good - I do particularly like the MF KW500, KW550 and KW750. I haven't heard too many other amps with serious power except for a few Pass Labs (X350 and X600) both of which are stunning, but then Nelson has a few patent tricks up his sleeve!
Anyway, is it finished and how does it sound?
be nice
to andrew t ...... he is always a very drastic and precise catalyst to our disscusions many of us should talk to him with at least respect.....
no hard feelings just my point of view ....
it would be nice to have schematic or atleast bloc diagarm to see how this board is working ....others might be ineterested to buy too ( inclooding me )
sakis
to andrew t ...... he is always a very drastic and precise catalyst to our disscusions many of us should talk to him with at least respect.....
no hard feelings just my point of view ....
it would be nice to have schematic or atleast bloc diagarm to see how this board is working ....others might be ineterested to buy too ( inclooding me )
sakis
I think the amps being discussed are low dynamic headroom.
High dynamic headroom implies high power on short transients and that power collapses when prolonged high power signals are demanded.
It is my opinion that a high dynamic headroom sounds poor in comparison to a high power amplifier.
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