Hi Riff, Welcome to the thread. 
Do you intend to use SSA as Subwoofer amp? Or multiple speakers in parallel? I believe the version you chose has the ability to drive 1.6ohm if you increase power transistors at the output. It has enough driver power for a lot of power trannies, but how many I cann't tell. Hope LC and others shed some light on this. I'm excited.
Do you intend to use SSA as Subwoofer amp? Or multiple speakers in parallel? I believe the version you chose has the ability to drive 1.6ohm if you increase power transistors at the output. It has enough driver power for a lot of power trannies, but how many I cann't tell. Hope LC and others shed some light on this. I'm excited.
ur wellcome shaan...hope i can learn something from this thread...my plane is multiple speakers in parallel for outdoor.Hi Riff, Welcome to the thread.
Do you intend to use SSA as Subwoofer amp? Or multiple speakers in parallel? I believe the version you chose has the ability to drive 1.6ohm if you increase power transistors at the output. It has enough driver power for a lot of power trannies, but how many I cann't tell. Hope LC and others shed some light on this. I'm excited.
anybody can tell me how rail to get 40vrms output at 1,6R?
7pair of 2SC5200/2SA1943 is enough?
With 7 pairs there will be over 3.5A of peak current through each device with 40VRMS(57VPeak) into 1.6ohm.
With 60VCE the SOA curve of 5200 tells max continuous Ic of just below 2A. So you'll need 13 pairs for driving that load from +-60V.
I hope I calculated it right.
edit: This would put 1Kw into 1.6ohms, so 13 pairs seems okay.
With 60VCE the SOA curve of 5200 tells max continuous Ic of just below 2A. So you'll need 13 pairs for driving that load from +-60V.
I hope I calculated it right.
edit: This would put 1Kw into 1.6ohms, so 13 pairs seems okay.
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I do not understand. this amp is able to deliver around 68V rms. What is your requirement, which usage ?
I believe 1.6R is not a big deal* if it was well calculated and will probably do not require much more power units as long you do not run-it on continuous power. Your main problem will be the power supply and cooling.
* Not sure, i don't designed-it and don't know the safety area of the power Transistors
[edit]Nice Shaan, our messages crossed.
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Yes you are right Christophe, none here has built it with so many output devices. I will wait for LC's input on this matter, as this approach hasn't been tried with SSA before. A successful 1KW SSA build will be a great project for the expansion of this topology into very high power range.
Care has to be taken regard to the driver's charge, not too much disparities between power units, or increase of their emitters resistances, forced air cooling etc...
As it, it looks ok to drive some special home speakers (condensers or magneplan) at good listening level.
> 1KW, for PA, by example, is just affraying. I would prefer Class D, for that kind of usage.
it is out of topic, but PA does not require such subtlety. It require clear, dynamic, and free reproduction, that all about Class D amp. Again, i wonder why Class D has such a bad reputation.
One of my friends, a very clever and passionated hifi and music lover, audiophile, in the good sense of the word, and DIYer had chosen Class D amps between everything else for his high end system to power those enclosures:
Enceintes acoustiques de référence (Look at the bottom of the page at the response curve and the group delay...)
The amps are here:
Mon système (use google translator ?) -> Amplificateur 2x300W classe D and http://www.dcx2496.fr/img/UHT849.jpg
He said it is the most transparent natural and dynamic amp he had never listened to.
Well, i hope he can compare, one day, with a SSA.
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At 1 kW I do not think anybody cares what it sounds like. If you are too close it is too loud, if you are too far then you cannot hear detail anyway.That's right Christophe. Class-D is actually better in this respect, but I doubt any Class-D can do what SSA can, sonically speaking.
If I am on the right track, we definitely need a Class-H SSA.
SSA MosFet
Hello , sorry for my bad english,
with great interest that I have followed this thread. At Home, i have many solid state Power Amplifier. Among others I have Sansui AU919, LC-Audio without feedbag, accuphase clone, Marantz clone with current feedbag. Best sounds the marantz amplifier, with current feedbag. For this reason I want to build an ssa mosfet amplifier. My question: how do I calculate the voltage of the Z-Diodes D3 and D4? Are 10 volts sufficient? With this configuration, i have a current of 14 mA to the cascode Q5 Q11.
Thanks and regards Gerd
Hello , sorry for my bad english,
with great interest that I have followed this thread. At Home, i have many solid state Power Amplifier. Among others I have Sansui AU919, LC-Audio without feedbag, accuphase clone, Marantz clone with current feedbag. Best sounds the marantz amplifier, with current feedbag. For this reason I want to build an ssa mosfet amplifier. My question: how do I calculate the voltage of the Z-Diodes D3 and D4? Are 10 volts sufficient? With this configuration, i have a current of 14 mA to the cascode Q5 Q11.
Thanks and regards Gerd
Attachments
Hi coolewater
Welcome to SSA thread.
It's not about zener voltage, it can be any value higher than feedback voltage drop on 100 ohm to GND resistors. In your case 5,6 V or higher. Important here are the values of current injected resistors R8, R10, who as the name says, inject current to the input stage and to 100 ohm to GND. In your case that sum would be app. 2,5 mA. You can change R8, R10 with CCS any time later, for the start it's just fine.
Since you'll operate with quite high supply voltages, heat dissipation on certain parts will be higher than normal, so good heatsinking required here is necessity.
Regards Andrej
Welcome to SSA thread.
It's not about zener voltage, it can be any value higher than feedback voltage drop on 100 ohm to GND resistors. In your case 5,6 V or higher. Important here are the values of current injected resistors R8, R10, who as the name says, inject current to the input stage and to 100 ohm to GND. In your case that sum would be app. 2,5 mA. You can change R8, R10 with CCS any time later, for the start it's just fine.
Since you'll operate with quite high supply voltages, heat dissipation on certain parts will be higher than normal, so good heatsinking required here is necessity.
Regards Andrej
Thank you :cheers
I bought for little money a broken Crescendo amp. The two transformers are from the Crescendo amp. Each Transformer has 2* 24 Volt AC, 340VA. From china i have bought a big case with heatsinks. Also i have a goldmund telos clone. I want to compare the ssa amp with the crescendo and the Golmund amp. If the SSA the better amp, i will replace one of the transformers, to a transformer with less voltage. I know I'm crazy :smilie
Gerd
I bought for little money a broken Crescendo amp. The two transformers are from the Crescendo amp. Each Transformer has 2* 24 Volt AC, 340VA. From china i have bought a big case with heatsinks. Also i have a goldmund telos clone. I want to compare the ssa amp with the crescendo and the Golmund amp. If the SSA the better amp, i will replace one of the transformers, to a transformer with less voltage. I know I'm crazy :smilie
Gerd
All along the numerous pages of this thread, near everything has been said to demonstrate the advantages of CFB vs VFB topology, on a musical point of view.
But one.
The coherency between small signals and large signals reproduction.
Looking at square waves as well at the frequency response curves, it is obvious.
And no VFB amp i know can reach that point.
I suppose it is significant in regard to the easy, coherent and fluid dynamic that offer SSA .
But one.
The coherency between small signals and large signals reproduction.
Looking at square waves as well at the frequency response curves, it is obvious.
And no VFB amp i know can reach that point.
I suppose it is significant in regard to the easy, coherent and fluid dynamic that offer SSA .
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