Quasi Fuses
A funny thing to be aware of regarding Quasi's (rail) fuses: If they do open, the amp continues to run and it sounds like the output has been destroyed.
At one point during construction I used an open fuse by mistake. It was very disheartening until I realised my error. Who can forget the the sound of an amp with dead outputs?
Shawn.
A funny thing to be aware of regarding Quasi's (rail) fuses: If they do open, the amp continues to run and it sounds like the output has been destroyed.
At one point during construction I used an open fuse by mistake. It was very disheartening until I realised my error. Who can forget the the sound of an amp with dead outputs? Shawn.
pcb size
Hello, I like the forum here. I am building the amp to match my 42-0-42 toroid. I am going for a 2-pair version. One thing doesn't seem to settle right, the size of the board. There doesn't seem to be any reference (a scale) on the image so I am unable to print to exact size.
Somebody help! Keypunch?
Hello, I like the forum here. I am building the amp to match my 42-0-42 toroid. I am going for a 2-pair version. One thing doesn't seem to settle right, the size of the board. There doesn't seem to be any reference (a scale) on the image so I am unable to print to exact size.
Somebody help! Keypunch?
Re: Those pesky capacitors
Quasi, thanks for your explaination. Actually, I still don't understand all of these jow, but I'll try later.
Thanks again for your file, quasi, you're so kind .
Today I'm gonna rewind my xformer, after rewind, I will have a 500VA 57-0-57,0-15,0-15,0-15 xformer for the amp, preamp and Dc detector. More pictures soon.
Regards,
Duong.
quasi said:
Quasi, thanks for your explaination. Actually, I still don't understand all of these jow, but I'll try later.
Thanks again for your file, quasi, you're so kind
.Today I'm gonna rewind my xformer, after rewind, I will have a 500VA 57-0-57,0-15,0-15,0-15 xformer for the amp, preamp and Dc detector. More pictures soon.
Regards,
Duong.
Re: pcb size
Hi davorinjo
If you decide to use Quasi's design, ask him, he's very kind. And if you choose my design, you can download it in post #791.
Regards,
Duong.
Hi davorinjo
All PCBs in this thread are designed using Sprintlayout, so print the design file directly using "Sprintlayout viewer" (free download at http://www.abacom-online.de/uk/html/sprint-layout.html) will help.davorinjo said:
If you decide to use Quasi's design, ask him, he's very kind. And if you choose my design, you can download it in post #791.
Regards,
Duong.
Re: Part 2
Hi Shawn
Now I now why you decide to build that amp, good luck with your solid amp. If there's anything interesting, tell me, I'm curious to see.
regards,
Duong
TomWaits said:
TomWaits said:but I want to explore more of the spectrum that Q put up in his selection table. So I am heading to the other side of the road just to see. I don't have much concern about the small-ish rails at +/-40 VDC. I think it will operate fantastically but I will post the results as I am building it anyway.
I exaggerated the power supply to accommodate Mr. T's and Q's tough Soar performance criteria. I am trying to build an amp with no limitations but itself. Each channel will have it's own 400VA transformer and 60,000uF of cap. power supply. I will be using only the best components I can get my hands on. It will be a solid amp. This is my goal and remember the 10 mosfet version I have is solid. I'm just curious I guess. Furthermore, no one that I know of, has built this amp in either direction I went. I want to explore Q's amp in different ways , I guess. Perhaps I just want to be different
Shawn.
Hi Shawn
Now I now why you decide to build that amp, good luck with your solid amp. If there's anything interesting, tell me, I'm curious to see
.regards,
Duong
Hi davorinjo,
Nive that you brought that up. I have never seen anyone putting scales on their pcb's except me. It makes other users easier to see if they have the iright size for the boards after the board images are transform, convert...., whatever many times. Bad habit or tradition maybe?
Nive that you brought that up. I have never seen anyone putting scales on their pcb's except me. It makes other users easier to see if they have the iright size for the boards after the board images are transform, convert...., whatever many times. Bad habit or tradition maybe?
Re: Headphone amp
The impedance of the 3rd stage is limited only by the 3 resistors.
R21 is there to force a degree of symmetry at clipping. It only offers a partial solution to cater for varying gate drive requirements (i.e. driving into different speaker loads). As mentioned earlier in this thread avoiding the assymetric clipping problem with this circuit is not possible without significant changes. In practical terms this "problem" is irrelevant.
Cheers
Q
TomWaits said:
The impedance of the 3rd stage is limited only by the 3 resistors.
R21 is there to force a degree of symmetry at clipping. It only offers a partial solution to cater for varying gate drive requirements (i.e. driving into different speaker loads). As mentioned earlier in this thread avoiding the assymetric clipping problem with this circuit is not possible without significant changes. In practical terms this "problem" is irrelevant.
Cheers
Q
Questions
Hi quasi, I have another questions:
1. In your softstart circuit, if I want to use 12V relay, what do I have to change?
2. Must I use a seperate xformer for the softstart circuit, or can I use the 0-15VAC line from main xformer?
3. the main line in my country is 220V, what else would be change? i read in ESP that the value of the 5W resistors depends on ac the main line and power rate of main xformer.
Thanks, quasi.
Hi quasi, I have another questions:
1. In your softstart circuit, if I want to use 12V relay, what do I have to change?
2. Must I use a seperate xformer for the softstart circuit, or can I use the 0-15VAC line from main xformer?
3. the main line in my country is 220V, what else would be change? i read in ESP that the value of the 5W resistors depends on ac the main line and power rate of main xformer.
Thanks, quasi.
You can use a relay rated to the voltage you are going to run the soft-start board at. Ie; you can run the board at 12 volts and use a 12 volt relay. Your timing will change though and with a 12 volt supply it will be longer. You can fix this by changing the charging resistor.
Or you can run the board off 24v DC and put a resistor in series with the relay coil. To halve the available voltage the resistor value should be about the same as the relay coil resistance.
You cannot use the secondary of the same transformer for this circuit because the transformer voltage will rise slowly and may never get to the voltage required by the slow start circuit before the resistors burn out (a few seconds). There are other ways of using the transformer secondary and I'll send something tonight (I'm at work now).
The values in the posted circuit will work fine for a 220v AC supply.
Cheers
Q
Umm ...why am I doing all the work here ? ...feel free to contribute anyone .....anyone??? hello...hello...... is this thing on? hello ?
Or you can run the board off 24v DC and put a resistor in series with the relay coil. To halve the available voltage the resistor value should be about the same as the relay coil resistance.
You cannot use the secondary of the same transformer for this circuit because the transformer voltage will rise slowly and may never get to the voltage required by the slow start circuit before the resistors burn out (a few seconds). There are other ways of using the transformer secondary and I'll send something tonight (I'm at work now).
The values in the posted circuit will work fine for a 220v AC supply.
Cheers
Q
Umm ...why am I doing all the work here ? ...feel free to contribute anyone .....anyone??? hello...hello...... is this thing on? hello ?
Quasi, thanks for your help!
Now I'm looking for a small transformer for the softstart circuit, I use 12V relay, so the the transformer should be 12VAC, right? Is it better if I use a bit higher Dc voltage for that circuit, such as 15VDC?
I found that your DC detector is quite identical to the one from Silicon Chip, except some small change, I think it's because SC use 12V relay, I'll post that schematic later.
Now I'm looking for a small transformer for the softstart circuit, I use 12V relay, so the the transformer should be 12VAC, right? Is it better if I use a bit higher Dc voltage for that circuit, such as 15VDC?
I found that your DC detector is quite identical to the one from Silicon Chip, except some small change, I think it's because SC use 12V relay, I'll post that schematic later.
I'm waiting for your work, Quasi
