Hi Lars,
Sometime back I had asked you how to select optimum value of the
drain resistor of T14 but I think you missed that post , could you please
answer that question now ??
Sometime back I had asked you how to select optimum value of the
drain resistor of T14 but I think you missed that post , could you please
answer that question now ??
Commentable Experienced Thoughts
Hi rajeev
The Quiescent current of our MUSTANG is 75mA per device.
Bhaji , I have seen ur PCB its good but lacks some finishing touches although but a nice attempt.
I will soon post the schematics of our new high slew rate amp on for DIYAUDIO FORUM.
And i will definitely give u PCB's of AMP+Protection free of cost so u can build our creation and feel the difference .
To LUMANAUW , RAHUL
One more thing the Slew Rate of Zeta is Asymmetricl which is not a good thing for yet to become PA amp as Pro World demands Symmetrical phenomena.
Rahul dont ask much illogical questions as they will not be answered by anyone.
Keep ur question to the point and have repect for fellow Indians at least.
Hope this helps to calm down every one's excitement or AXIETY
Hi rajeev
The Quiescent current of our MUSTANG is 75mA per device.
Bhaji , I have seen ur PCB its good but lacks some finishing touches although but a nice attempt.
I will soon post the schematics of our new high slew rate amp on for DIYAUDIO FORUM.
And i will definitely give u PCB's of AMP+Protection free of cost so u can build our creation and feel the difference .
To LUMANAUW , RAHUL
One more thing the Slew Rate of Zeta is Asymmetricl which is not a good thing for yet to become PA amp as Pro World demands Symmetrical phenomena.
Rahul dont ask much illogical questions as they will not be answered by anyone.
Keep ur question to the point and have repect for fellow Indians at least.
Hope this helps to calm down every one's excitement or AXIETY
Ampman
Thanks for the offer , can it be soon so that I can have the amp ready for the newyear bash .
Reg my pcb ..... its a DIY job handpainted and ALL one man job , but very satisfying .
I must meet you some day
cheers
Rajeev
Thanks for the offer , can it be soon so that I can have the amp ready for the newyear bash .
Reg my pcb ..... its a DIY job handpainted and ALL one man job , but very satisfying .
I must meet you some day
cheers
Rajeev
Hi, Ampman,
I will be looking forward for your professional and experienced design. Hope it is not too long until you post it here. 😀
I will be looking forward for your professional and experienced design. Hope it is not too long until you post it here. 😀
I don't know which ISO standard you read. You should give email to QSC, because they use NE5532 (which is not symmetrical design) for the brain of all their amps line
How true and not to put up illogical designs rather spices either.
Great Amp_man. I pray the new design that you intend to post is not on similar lines to many other postings all over the forum by one professional Mosfet amp designer.
Regards
Rahul
Confirmation on Affirmation
Hi Rajeev,
I will give u the PCB's in 2 to 3 weeks time and then u Build the amp and then Post ur experience.
Simuntaneously I will also start a new thread in which u can share the experience of our design.
I also want to meet u not some day but maybe in some....???
Cheerup Rahul and feel Good as India is Shining.
Lumanauw
Have u ever seen the manual of any QSC amp in detail.
They Haven't mentioned any info regarding the Slew rate of their amp at any where.
Regards
WORKHORSE TECHNOLOGIES
rajeev luthra said:
Hi Rajeev,
I will give u the PCB's in 2 to 3 weeks time and then u Build the amp and then Post ur experience.
Simuntaneously I will also start a new thread in which u can share the experience of our design.
I also want to meet u not some day but maybe in some....???
Cheerup Rahul and feel Good as India is Shining.
Lumanauw
Have u ever seen the manual of any QSC amp in detail.
They Haven't mentioned any info regarding the Slew rate of their amp at any where.
Regards
WORKHORSE TECHNOLOGIES
I think it's time this thread goes back to about the zeta.
I have rebuilt mine and mounted everything on a 6" long 1" 90° aluminum bar. that's all the heatsinking I had while testing everything on +/-33V. pushed the amp for about 20mins at 10-15W RMS (with a small fan) and it sounded good. imaging is not that nice (although it's in my workshop with bose speakers and just a listening test. but the zeta did have a good grip on the bass. treble, a bit harsh, not sure if it's the amp, or I have only 20mA bias, or the piezo tweeters or all of those. but the zeta did sound good. no hum, very little hiss (had to stick the tweeter in my ear just to hear a tiny bit of hiss probably coming from my CD player)
I hardwired only a pair of RFH30N15 devices per channel to the aluminum bar. haven't checked the datasheets on these but I think they are 150V 30A devices. DC offset at output is around 70mV and the other channel is around 130mV. probably acceptable to most speakers? lowered the voltage gain to about 20 to match the rail voltages.
I have rebuilt mine and mounted everything on a 6" long 1" 90° aluminum bar. that's all the heatsinking I had while testing everything on +/-33V. pushed the amp for about 20mins at 10-15W RMS (with a small fan) and it sounded good. imaging is not that nice (although it's in my workshop with bose speakers and just a listening test. but the zeta did have a good grip on the bass. treble, a bit harsh, not sure if it's the amp, or I have only 20mA bias, or the piezo tweeters or all of those. but the zeta did sound good. no hum, very little hiss (had to stick the tweeter in my ear just to hear a tiny bit of hiss probably coming from my CD player)
I hardwired only a pair of RFH30N15 devices per channel to the aluminum bar. haven't checked the datasheets on these but I think they are 150V 30A devices. DC offset at output is around 70mV and the other channel is around 130mV. probably acceptable to most speakers? lowered the voltage gain to about 20 to match the rail voltages.
Ampman,
Yes, big pro amps generally (but not all) have symmetrical design, using full complementary discrete differential. They do have symmetrical slew rate. Also have bigger OL gain too. This leads to bigger feedback, can result in higher damping factor.
People usually look in damping factor, slew-rate when they choose pro-amps.
Amp-man, some of members here likes seeing your comments. You kind of having a fans club here. If I were you, I would be very happy.😀 Imagine you have no one responds to your comments, it would be sad.
I tought you should be able to predict is it symmetrical or non symmetrical slewrate by seeing the schematic. So, it must be you have built ZETA and knows that it doesn't have symmetrical slew rate?
Yes, big pro amps generally (but not all) have symmetrical design, using full complementary discrete differential. They do have symmetrical slew rate. Also have bigger OL gain too. This leads to bigger feedback, can result in higher damping factor.
People usually look in damping factor, slew-rate when they choose pro-amps.
Amp-man, some of members here likes seeing your comments. You kind of having a fans club here. If I were you, I would be very happy.😀 Imagine you have no one responds to your comments, it would be sad.
Lars Clausen said:
if that's the case, I don't think the "not being symmetrical" matters with music signals.
Well since both negative and positive slopes have the same slew rate, there is not much unsymmetry to be seen on the scope.
Below you can see the first of the evaluation PCB's for Nexus.
It is equipped with 2 IRF260 on the back side, fastened to the heat sink with the visible screws. Here it runs with a 42V transformer, giving 60V rails and tested to give 180W in 8 Ohms continous power. There are no difference in gain with changing rail voltage in this setup. As you can see the board is quite small (only 48 by 69 mm - smaller than a business card) this can be accomplished through the use of SMD parts. Critical resistors are melf metal film, while less critical ones are normal chip resistors. The sound is quite good!
With bigger MOSFET's (Like APT50M65LLL, which will fit right in) it can produce a lot more power than this.
Below you can see the first of the evaluation PCB's for Nexus.
It is equipped with 2 IRF260 on the back side, fastened to the heat sink with the visible screws. Here it runs with a 42V transformer, giving 60V rails and tested to give 180W in 8 Ohms continous power. There are no difference in gain with changing rail voltage in this setup. As you can see the board is quite small (only 48 by 69 mm - smaller than a business card) this can be accomplished through the use of SMD parts. Critical resistors are melf metal film, while less critical ones are normal chip resistors. The sound is quite good!
With bigger MOSFET's (Like APT50M65LLL, which will fit right in) it can produce a lot more power than this.
An externally hosted image should be here but it was not working when we last tested it.
Member
Joined 2002
Hi, LC,
VERY NICE !!! I never would have guess it will be that small.
Do you have SMD machine in your garage? How come you can make prototype (1pcs) with SMD?
VERY NICE !!! I never would have guess it will be that small.
Do you have SMD machine in your garage? How come you can make prototype (1pcs) with SMD?
Lars
Great Pcb , Now more people can make THE ZETA easily .
Sorry to ask the same question again , but you overlooked it again.....
Sometime back I had asked you how to select optimum value of the drain resistor of T14 but I think you missed that post , could you please answer that question now ??
__________________
Great Pcb , Now more people can make THE ZETA easily .
Sorry to ask the same question again , but you overlooked it again.....
Sometime back I had asked you how to select optimum value of the drain resistor of T14 but I think you missed that post , could you please answer that question now ??
__________________
Confirmation on Affirmation
LumanauW,
I haven't build the Zeta , the slewrate is asymmetrical because there is a delay caused by the insertion of P-channel inverter mosfet for driving the negative rail mosfets whereas positive rail mosfets r driven directly from bipolars.
Secondly have u ever seen the schematic of Crown amps which exclusively use GROUNDED BRIDGE TOPOLOGY and Their Damping Factor is around 2000 to 3000 and that too in Bridge configuration, therefore the slewrate effects the damping factor also.
I dont think People here like my comments but they rather want to play games with us.
Hi Lars
How do u measure the slew rate of ur amp, Secondly a slewrate must be measured both with Negative and positive drive and simply quoting 50V/us is not a viable way rather than u must mention the slew rate in + and - drive terms and then affirmate it , whether it is symmtric or not.
Yours Sincerely
Kanwar Abhishek Singh
lumanauw said:
LumanauW,
I haven't build the Zeta , the slewrate is asymmetrical because there is a delay caused by the insertion of P-channel inverter mosfet for driving the negative rail mosfets whereas positive rail mosfets r driven directly from bipolars.
Secondly have u ever seen the schematic of Crown amps which exclusively use GROUNDED BRIDGE TOPOLOGY and Their Damping Factor is around 2000 to 3000 and that too in Bridge configuration, therefore the slewrate effects the damping factor also.
I dont think People here like my comments but they rather want to play games with us.
Lars Clausen said:
Hi Lars
How do u measure the slew rate of ur amp, Secondly a slewrate must be measured both with Negative and positive drive and simply quoting 50V/us is not a viable way rather than u must mention the slew rate in + and - drive terms and then affirmate it , whether it is symmtric or not.
Yours Sincerely
Kanwar Abhishek Singh
Re: Confirmation on Affirmation
Maybe so, but I'm sure people would prefer you to contribute more in the development. So far you have said mostly that everything is wrong. The amp maybe has rather symmetrical slew rate, not so much difference so it's visible.amp_man_1 said:
Re: Re: Confirmation on Affirmation
P-E-R-A-N-D-E-R-S,
Hi MODERATOR,
i havent said anything wrong or nor i had made any illogical comments , What i said is atruth and nothing else.
whether some people like it or not, but i dont care.
peranders said:
P-E-R-A-N-D-E-R-S,
Hi MODERATOR,
i havent said anything wrong or nor i had made any illogical comments , What i said is atruth and nothing else.
whether some people like it or not, but i dont care.
most of the posts of yours that I saw criticize designs and say that your designs are the best. even in other threads.
it would be nice if you would say something like what components to change or modify so that we could get better performance.