Hi,
there are a range of low power to high power amps from Quasi.
All work well and have designer support.
What is the point in trying to increase the power of the lowest power amp and risking all the problems that go with this type of experimentation?
It will be much easier to simply select a higher power model and know it will work as specified.
there are a range of low power to high power amps from Quasi.
All work well and have designer support.
What is the point in trying to increase the power of the lowest power amp and risking all the problems that go with this type of experimentation?
It will be much easier to simply select a higher power model and know it will work as specified.
hi andrew,
it is for qsa to increase the range,
my concern is bridging even actrk600 or nmos400,
for my sub,outdoor purposes
it is for qsa to increase the range,
my concern is bridging even actrk600 or nmos400,
for my sub,outdoor purposes
Hi,. AndrewT
>What is the point in trying to increase the power of the lowest power amp
Much todays amps dont sounding good, I remember old BGW 750B, stable for 24/7 this amplifiers sounding much more better, deeper in bass, natural in high and mid in my favourite nightclub from 1978 - 2000 with RLA Richard Long Sound System than a lot of todays amplifier
I like tube and mosfet sound, there is a different in sound with good design compare to bjts...its not esoteric !
I think quasis nmos design will be one of best sounding HIGH END PA Amplifier......
I do it for fun, I get from client for free 3 defective heavy 40 kg PA Amplifier from unknown chinese supplier with design faults in amplifier pcb.... good for me, i have no cost for transformer, power supply capacitors. housing
I have remove original BJT amplifier pcbs and will replace with new designed quasi nmos pcb.... the rail is +/-130V for output stage and +/-140 V for driver stage
I did some changes in quasi design for higher rails, additional VI limiter + Clip limiter, Clip, Signal, Protect LED, 2 Speed Fan Control and auto Fan off for Hi-Fi use if Heatsinks < 45 degrees
I hope my design dont blow after first turn on....
This weekend I will finished redesign BGW 750B amplifier pcb, add a little improvements such as NE5534a OP than old LM318, other capacitors and so on,
I send next week pcb layout for nmos and bgw 750b redesign to PCB manufacturer
If somebody want share experience in this forum,... yes
What is happend with quasi ? Long time nothings hear....
@ engel dela pena
> my concern is bridging even actrk600 or nmos400
Do you want share experience ? please email me
>What is the point in trying to increase the power of the lowest power amp
Much todays amps dont sounding good, I remember old BGW 750B, stable for 24/7 this amplifiers sounding much more better, deeper in bass, natural in high and mid in my favourite nightclub from 1978 - 2000 with RLA Richard Long Sound System than a lot of todays amplifier
I like tube and mosfet sound, there is a different in sound with good design compare to bjts...its not esoteric !
I think quasis nmos design will be one of best sounding HIGH END PA Amplifier......
I do it for fun, I get from client for free 3 defective heavy 40 kg PA Amplifier from unknown chinese supplier with design faults in amplifier pcb.... good for me, i have no cost for transformer, power supply capacitors. housing
I have remove original BJT amplifier pcbs and will replace with new designed quasi nmos pcb.... the rail is +/-130V for output stage and +/-140 V for driver stage
I did some changes in quasi design for higher rails, additional VI limiter + Clip limiter, Clip, Signal, Protect LED, 2 Speed Fan Control and auto Fan off for Hi-Fi use if Heatsinks < 45 degrees
I hope my design dont blow after first turn on....
This weekend I will finished redesign BGW 750B amplifier pcb, add a little improvements such as NE5534a OP than old LM318, other capacitors and so on,
I send next week pcb layout for nmos and bgw 750b redesign to PCB manufacturer
If somebody want share experience in this forum,... yes
What is happend with quasi ? Long time nothings hear....
@ engel dela pena
> my concern is bridging even actrk600 or nmos400
Do you want share experience ? please email me
qsa said:
Quasi is still around but busy renovating his house and helping a friend with his Nmos350 project and his transmission line speaker project and taking kids to sports and doing woodwork stuff around the house and trying to finish Nmos MkII and too much stuff without enough time.
Anyway I see no reason for a bridging adaptor to not work although I have personally not tried it. With the right FETs the Actrk600 can deliver around 800 watts into 4 ohms single ended so consider this option also. If you do go bridge remember that the amplifier modules will see half the actual speaker impedance i.e; if you use an 4 ohm speaker the bridged amplifier will see 2 ohms. You need to keep this in mind when you configure the output stage.
Sorry about not answering some emails, I get a lot.
Cheers
Q
i know that soft start,dc detect are included in nmos/actrk hope someday nmos/actrk can be bridged just by a selector switch/slide switch,means diy'er can easily choose both application according to what he need just like those marketed amplifier these days,with stereo or bridge mono selector
here how it works,
from sam electronic circuit,
This is a very useful circuit for those who want to transform a stereo Power Amplifier, to mono, bridging two channels from him , reversing the phase of the one power amplifier [R] and the polarity, with these connections we can have 4X times the output power (double the output voltage ) . For example : if we use the circuit to a stereo amplifier 2X50W, will have 1X200W output , if power supply assent.
How to Work?
In the connector J1, we can connect two type plugs (XLR) Cannon, and input of two channels it's symmetric (electronic balance). With potesometer VR1 and VR2, we regulate the level of each channel separately (stereo), switch S1a-b [place 2]. When bridging two amplifiers, with the switch S1a-b [place 1], then the level him we regulate only with the VR1. The department of channel [ R ] is suppressed and the input is given only in [ L ] channel. Simultaneously inputs in use the inversion department of phase round the IC1c, driving second power amp. [ R ], with reverse polarity, from [ L ] channel. The output now it should him we take from two [+] positive output final amplifiers. In the circuit it appears association the loudspeakers and for the two cases (stereo - bridge). In order to we have results of precision, should the resistances of input differential amplifiers, be metal film 1%, pontesometer, the capacitors and switch S1, good quality. The power supply of circuit is ± 15V, stabilised. If you want to use the inputs, no as symmetrical (balance), but as asymmetrical (unbalance), you can connect in 0V, the negative inputs of signal J1/1 [L/mono] and J1/5[R ]. The asymmetrical signal now enters in the positive inputs, J1/2 and J1/6.
Part List
R1-2= 47Kohms C1-2= 1uF 100V 5% IC1= TL074
R3-4= 47Kohms C3-4= 1uF 100V 5% S1= 2X2 SW.
R5-6= 47Kohms C5-6= 33pF VR1-2= 10Kohms Log. pot.
R7-8= 47Kohms C7-8= 33pF .
R9-10-11=47Kohms C9-11= 100nF 100v .
R12-13= 22 ohms C10-12= 47uF 25V .
Áll metal film 1/4W 1% J1-2= 6pin Connector .
from sam electronic circuit,
This is a very useful circuit for those who want to transform a stereo Power Amplifier, to mono, bridging two channels from him , reversing the phase of the one power amplifier [R] and the polarity, with these connections we can have 4X times the output power (double the output voltage ) . For example : if we use the circuit to a stereo amplifier 2X50W, will have 1X200W output , if power supply assent.
How to Work?
In the connector J1, we can connect two type plugs (XLR) Cannon, and input of two channels it's symmetric (electronic balance). With potesometer VR1 and VR2, we regulate the level of each channel separately (stereo), switch S1a-b [place 2]. When bridging two amplifiers, with the switch S1a-b [place 1], then the level him we regulate only with the VR1. The department of channel [ R ] is suppressed and the input is given only in [ L ] channel. Simultaneously inputs in use the inversion department of phase round the IC1c, driving second power amp. [ R ], with reverse polarity, from [ L ] channel. The output now it should him we take from two [+] positive output final amplifiers. In the circuit it appears association the loudspeakers and for the two cases (stereo - bridge). In order to we have results of precision, should the resistances of input differential amplifiers, be metal film 1%, pontesometer, the capacitors and switch S1, good quality. The power supply of circuit is ± 15V, stabilised. If you want to use the inputs, no as symmetrical (balance), but as asymmetrical (unbalance), you can connect in 0V, the negative inputs of signal J1/1 [L/mono] and J1/5[R ]. The asymmetrical signal now enters in the positive inputs, J1/2 and J1/6.
Part List
R1-2= 47Kohms C1-2= 1uF 100V 5% IC1= TL074
R3-4= 47Kohms C3-4= 1uF 100V 5% S1= 2X2 SW.
R5-6= 47Kohms C5-6= 33pF VR1-2= 10Kohms Log. pot.
R7-8= 47Kohms C7-8= 33pF .
R9-10-11=47Kohms C9-11= 100nF 100v .
R12-13= 22 ohms C10-12= 47uF 25V .
Áll metal film 1/4W 1% J1-2= 6pin Connector .
No,engel dela pena said:
double the power into double the impedance.
From your example 50W+50W into 8r0 becomes 100W into 16r0.
But, you can feed the 50W into two 8ohm speakers and still get a total output of 100W. You have gained nothing by bridging.
The new schematic shows Ic1a & 1b as inverting, but with the feedback to the wrong input terminal.
Can anyone confirm that these two Ics have been labeled incorrectly?
If these are incorrectly labeled then the unbalanced jumpers go from j1 to 0V and from j5 to 0V.
Finally, the inputs to each channel are not balanced. Either use transformers or add in the extra opamps for electronic balancing if that is what is required to match your source.
check this site,
sam electrnic circuit,
http://users.otenet.gr/~athsam/bridge_converter.htm
so what was the benifit of bridging two nmos or two actrk?
sam electrnic circuit,
http://users.otenet.gr/~athsam/bridge_converter.htm
so what was the benifit of bridging two nmos or two actrk?
ask the Car Audio Guys & Gals.engel dela pena said:
It seems to impress the hell out of those that don't know any better.
andrewT,
Those schematic are not mine and its not my axplanation how it works,just downloaded it from the said site,
anyway,maybe i'm just too much into bridging diy people,
its just because when i compare my uncle's pa sound when he change stereo mode into bridge mono,i realy feel the difference much power i can hear,i'm speaking of crown amp,but its not only in crown,sometimes japan made and china made brigable amp i experienced.
so to anyone who can help bridging an nmos or actrk please share to this forum
Those schematic are not mine and its not my axplanation how it works,just downloaded it from the said site,
anyway,maybe i'm just too much into bridging diy people,
its just because when i compare my uncle's pa sound when he change stereo mode into bridge mono,i realy feel the difference much power i can hear,i'm speaking of crown amp,but its not only in crown,sometimes japan made and china made brigable amp i experienced.
so to anyone who can help bridging an nmos or actrk please share to this forum
bridge adaptor
hi
will send bridge adaptor schematic tomorrow have you made actr
600 is it that powerful
have made quasi bipolar very clean circuit can you tell me how much
power output will nmos amplifier designed by qsa givewhich mosfet
is better irf450 or irf460
thanking you
andrew lebon
hi
will send bridge adaptor schematic tomorrow have you made actr
600 is it that powerful
have made quasi bipolar very clean circuit can you tell me how much
power output will nmos amplifier designed by qsa givewhich mosfet
is better irf450 or irf460
thanking you
andrew lebon
andrewlebon,
yes nmos200 i use irfp460
actrk i'm still thingking irfp460 or 2sk578 bec. these two nmos is all i have in my bunch maybe enough to build two module.
1rf450 500v, 12a, 150w TO-3 good for nmos400
irf460 500v, 300w, TO-3 better for nmos 400
n-bip350 good, read thread brother of quasi
yes nmos200 i use irfp460
actrk i'm still thingking irfp460 or 2sk578 bec. these two nmos is all i have in my bunch maybe enough to build two module.
1rf450 500v, 12a, 150w TO-3 good for nmos400
irf460 500v, 300w, TO-3 better for nmos 400
n-bip350 good, read thread brother of quasi
andrewlebon,
qsa 135+/- supply,let us wait till he complete his work,
power amp under development is aged to perfection,
it is a continous development,thanks to quasi & all people sharing
for the spirit of this diy is sharing,long live the diy'er
qsa 135+/- supply,let us wait till he complete his work,
power amp under development is aged to perfection,
it is a continous development,thanks to quasi & all people sharing
for the spirit of this diy is sharing,long live the diy'er
hellow!
Is there any short circuit protection for the amp NMOS350/500 availible?
there is too much transistors to change, if the output of the amp is in short circuit
I would like to do nmos500 amp 2 channels for PA speakers, and i would like to know, if its better to have 2 power supplyes(one for one amp, second for second amp) or it can be done by one power supply(transformator wil have the power of around 1.5kW)
Is there any short circuit protection for the amp NMOS350/500 availible?
there is too much transistors to change, if the output of the amp is in short circuit
I would like to do nmos500 amp 2 channels for PA speakers, and i would like to know, if its better to have 2 power supplyes(one for one amp, second for second amp) or it can be done by one power supply(transformator wil have the power of around 1.5kW)
Yes there is short protection for the amp NMOS350/500
actually im not at home, if you want send me your email adress
for discuss and share experience
actually im not at home, if you want send me your email adress
for discuss and share experience
power amplifier
hi qsa
greetings howis your amp going what is its output power rms
have you completed the pcb will you post picture of it looks very
powerful hexfets are very cheap and no fakes wishing you good luck
on your project i am very excited bye
andew lebon
hi qsa
greetings howis your amp going what is its output power rms
have you completed the pcb will you post picture of it looks very
powerful hexfets are very cheap and no fakes wishing you good luck
on your project i am very excited bye
andew lebon
Hi,
Sorry Guys, I need a little time about 2-4 weeks because so much to do in my job.
I want add Crowbar Speaker Protection for NMOS but its impossibile to get TRIAC 2N6346A and MBS4991 Thyrisistor because obsolete, does somebody have idea for replacement with new devices ?
A lot of professional amplifier manufacturer in the past used TRIAC 2N6346A and MBS4991 Thyrisistor as Crowbar Speaker Protection
NMOS schematic is finished and has Class AB + B Output Stage with Short Circuit protection but not tested until now.....
Mosfets: IRFP460
Voltage: 40 - 130 V +/- without any changes
First time I will order by PCB Supplier small 240 x 100 mm sample PCB with 8 Mosfets (2 x 4) to test Class AB+B NMOS for faults, after this I will order big PCB with 22 Mosfets (2 x 11)
I think about big 130 V NMOS to design as CLASS G because its much more efficient but I need a little assistance...
At least, I have redesign old BGW 750B PA Amplifier with a little improvements like NE5534a OP IC compare to old LM318h and improvement in Short Circuit protection and capacitors, its since today a very good sounding and stable working Professional Amp
The bass on the BGW 750B is deeper & rounder and in fullrange also much more musical than competitors, it`s just very warm & very natural sounding just a better sounding amp all together, you can listen long time music without headache
NMOS and 750B redesign have now identical short Circuit protection, turn on delay is from quasi + additional status LED like..... modulation, protect, overload/Clip
I use TARGET for PCB design, if somebody has target and interested for schematic to share experience I can email
@quasi
and trying to finish Nmos MkII and too much stuff without enough time
please send us more infos about your ideas in improvement....
how do you think about Class G / Class H NMOS design for more efficiency ?
Very good sounding amps are rare in the market......
Sorry Guys, I need a little time about 2-4 weeks because so much to do in my job.
I want add Crowbar Speaker Protection for NMOS but its impossibile to get TRIAC 2N6346A and MBS4991 Thyrisistor because obsolete, does somebody have idea for replacement with new devices ?
A lot of professional amplifier manufacturer in the past used TRIAC 2N6346A and MBS4991 Thyrisistor as Crowbar Speaker Protection
NMOS schematic is finished and has Class AB + B Output Stage with Short Circuit protection but not tested until now.....
Mosfets: IRFP460
Voltage: 40 - 130 V +/- without any changes
First time I will order by PCB Supplier small 240 x 100 mm sample PCB with 8 Mosfets (2 x 4) to test Class AB+B NMOS for faults, after this I will order big PCB with 22 Mosfets (2 x 11)
I think about big 130 V NMOS to design as CLASS G because its much more efficient but I need a little assistance...
At least, I have redesign old BGW 750B PA Amplifier with a little improvements like NE5534a OP IC compare to old LM318h and improvement in Short Circuit protection and capacitors, its since today a very good sounding and stable working Professional Amp
The bass on the BGW 750B is deeper & rounder and in fullrange also much more musical than competitors, it`s just very warm & very natural sounding just a better sounding amp all together, you can listen long time music without headache
NMOS and 750B redesign have now identical short Circuit protection, turn on delay is from quasi + additional status LED like..... modulation, protect, overload/Clip
I use TARGET for PCB design, if somebody has target and interested for schematic to share experience I can email
@quasi
and trying to finish Nmos MkII and too much stuff without enough time
please send us more infos about your ideas in improvement....
how do you think about Class G / Class H NMOS design for more efficiency ?
Very good sounding amps are rare in the market......