I looked over the anticlip circuit. I understand how it works... more or less...
Could someone tell me what the 2 arrows in the big schematic, the first one, mean? The arrows pointing up and down, right under the last op-amp.
Better, so i don't do something stupid, can someone implement it in the big schematic?
I know i've been asking a lot from you guys but i really appreciate the effort you are putting for this and i want to sincerely thank you. Once i finish it i promise i'll credit you wherever i go and put my amp to work.
Could someone tell me what the 2 arrows in the big schematic, the first one, mean? The arrows pointing up and down, right under the last op-amp.
Better, so i don't do something stupid, can someone implement it in the big schematic?
I know i've been asking a lot from you guys but i really appreciate the effort you are putting for this and i want to sincerely thank you. Once i finish it i promise i'll credit you wherever i go and put my amp to work.
Hi Guys
Solid arrows pointing up and down are positive and negative supplies, respectively.
These should be +/-15V or so, regulated and clean.
Have fun
Kevin O'Connor
Solid arrows pointing up and down are positive and negative supplies, respectively.
These should be +/-15V or so, regulated and clean.
Have fun
Kevin O'Connor
To my understanding, to connect, say circuit B, i get rid of R22 and just connect it to the left of the circuit above, to the 2 33k resistors, connect the VC points and eliminate r23, r24, c8, c9 and connect it to what i have on the original blameless schematic? Then i supply it with +-15 vdc and it should work? Any chance of doing all of this on the big amp board and also supplying it off the big +-80v rails?
Also, which one is better over all? Circuit a or b? Not necessarily more accurate, but less degrading to the input signal?
Also, which one is better over all? Circuit a or b? Not necessarily more accurate, but less degrading to the input signal?
Hi Guys
Both forms work fine except A can be noisier in practice. A confusing issue might be the basic noisiness of the PV CS-800...
There is a little overlap between the no-clip and PA schematics. Any circuit that accepts signals from the outside world should be bandwidth limited right at the input. As you describe, Brlmat, remove the "usual input filtering" from the no-clip and instead use the identical network on the PA schematic, then break that circuit to insert the no-clip audio path portion, is fine.
There must be a DC path to ground for the PA input. It is preferred to capacitively couple from the no-clip to the PA input to minimise DC disturbance at the diff amp.
Yes, everything can be on one board. How you generate the +/-15V is up to you. Simple passive regulators (zeners) will do, and buffered regulators are better.
Have fun
Kevin O'Connor
Both forms work fine except A can be noisier in practice. A confusing issue might be the basic noisiness of the PV CS-800...
There is a little overlap between the no-clip and PA schematics. Any circuit that accepts signals from the outside world should be bandwidth limited right at the input. As you describe, Brlmat, remove the "usual input filtering" from the no-clip and instead use the identical network on the PA schematic, then break that circuit to insert the no-clip audio path portion, is fine.
There must be a DC path to ground for the PA input. It is preferred to capacitively couple from the no-clip to the PA input to minimise DC disturbance at the diff amp.
Yes, everything can be on one board. How you generate the +/-15V is up to you. Simple passive regulators (zeners) will do, and buffered regulators are better.
Have fun
Kevin O'Connor
Hi Guys
Regarding my comments about the HB in post 110:
Those comments apply to the dx blame project. That one reverts the circuit back to 1970s methods and performance.
The HB is still compromised inasmuch as it should have a predriver stage. and the offset adjust might impair input stage balance. Both of these combine to make distortion twice what it should be. That sounds dramatic but it may be the difference between 0.009% and 0.0045% at mid frequencies. Worry a bit less, Rick.
Have fun
Kevin O'Connor
Regarding my comments about the HB in post 110:
Those comments apply to the dx blame project. That one reverts the circuit back to 1970s methods and performance.
The HB is still compromised inasmuch as it should have a predriver stage. and the offset adjust might impair input stage balance. Both of these combine to make distortion twice what it should be. That sounds dramatic but it may be the difference between 0.009% and 0.0045% at mid frequencies. Worry a bit less, Rick.
Have fun
Kevin O'Connor
Whew! I feel better. 😀 I'm going to proceed with the standard HB build (latest rev) to ensure I get a working amp first. Then I'll consider any mods that will improve performance. I for sure, can't hear the difference between .009 and .0045% THD!
Rick
Btw, the schematic you, Struth, gave me, has it been tested? Did anyone actually build it? Can i be sure that it will work ?
Hi Guys
Yes, the circuit has been built and used thousands of times. Nothing new here. Very conventional and safe.
Have fun
Kevin O'Connor
Yes, the circuit has been built and used thousands of times. Nothing new here. Very conventional and safe.
Have fun
Kevin O'Connor
Great! Now we need a PCB. I almost popped on the DX BlameMKIII but I would really rather build this one. How bout it?
I will ask alex_mm to see if he can do it. I don't know him personally nor have i talked to him what so ever but i'll ask him nicely.
Hi Guys
As I said in post 126:
"A board design really depends on what heat sinks you have available to you. You end up with all the outputs in one line across the width of a low wide heatsink, i.e. one used to form the side of a chassis, or you have two rows of outputs on opposite edges of the board on a more square heat sink like Terry used for his Super amp."
There probably is not a single board that would satisfy everyone.
With all the output devices in one line, one dimension of the heat sink must exceed 195mm (7.7"). The board would stick out from the heat sink by 2-3" depending on how the rest of the circuitry can be distributed without making traces too long. This does not have much if any local filtering on the board.
There must be space between the channels for the PT and main filters. It is best to go with many parallel filters for the best transient response and to improve the power supply frequency response. If everyone is using 80-90V rails, then 100V caps would be the best choice. These would likely be snap-mounts, with the standard 10mm lead pitch. Best to stick with this form rather than go to the 3,4 or 5 pin caps.
Another facet is that an interface plate might be required so that the fin spacing make no difference to the transistor spacing. If you have a known heat sink, you can space the BJTs so they are centered on the flats between the fins, making drilling and bolting easier. Otherwise, you have to drill and tap blind holes. Using a thick piece of flat aluminum as an interface makes the BJT spacing and fin spacing independent.
Where some builders have the board parallel to the flat plane of the heat sink, this can be a bad idea in a high power amp. The heat from this face can damage the solder connections over time, and it certainly heats up the front end of the amp. That can cause THD to rise or for the DC offset to drift. So, even if you were building the board in the other fashion - with two rows of outputs on opposite edges, and thus a power card parallel to the heat sink - it would be advisable to have the front end be on a separate board that plugs into the power card.
As you can see from the above, there are many possible layouts ultimately. A lot is determined by the physical size of the components and the rest by mechanical factors and availability.
I can design a board for whichever shape you deem most popular.
Have fun
Kevin O'Connor
As I said in post 126:
"A board design really depends on what heat sinks you have available to you. You end up with all the outputs in one line across the width of a low wide heatsink, i.e. one used to form the side of a chassis, or you have two rows of outputs on opposite edges of the board on a more square heat sink like Terry used for his Super amp."
There probably is not a single board that would satisfy everyone.
With all the output devices in one line, one dimension of the heat sink must exceed 195mm (7.7"). The board would stick out from the heat sink by 2-3" depending on how the rest of the circuitry can be distributed without making traces too long. This does not have much if any local filtering on the board.
There must be space between the channels for the PT and main filters. It is best to go with many parallel filters for the best transient response and to improve the power supply frequency response. If everyone is using 80-90V rails, then 100V caps would be the best choice. These would likely be snap-mounts, with the standard 10mm lead pitch. Best to stick with this form rather than go to the 3,4 or 5 pin caps.
Another facet is that an interface plate might be required so that the fin spacing make no difference to the transistor spacing. If you have a known heat sink, you can space the BJTs so they are centered on the flats between the fins, making drilling and bolting easier. Otherwise, you have to drill and tap blind holes. Using a thick piece of flat aluminum as an interface makes the BJT spacing and fin spacing independent.
Where some builders have the board parallel to the flat plane of the heat sink, this can be a bad idea in a high power amp. The heat from this face can damage the solder connections over time, and it certainly heats up the front end of the amp. That can cause THD to rise or for the DC offset to drift. So, even if you were building the board in the other fashion - with two rows of outputs on opposite edges, and thus a power card parallel to the heat sink - it would be advisable to have the front end be on a separate board that plugs into the power card.
As you can see from the above, there are many possible layouts ultimately. A lot is determined by the physical size of the components and the rest by mechanical factors and availability.
I can design a board for whichever shape you deem most popular.
Have fun
Kevin O'Connor
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I was actually thinking of having all the output devices in a row. The problem is that i can't get hold of alex's public profile. I simply can't find it.
Also, do you know how this amp sounds like? Detailed and warm? Cold?
Also, do you know how this amp sounds like? Detailed and warm? Cold?
Thank you Vostro. I found it myself eventually.
Struth, i already sent him a pm asking him if he could do it just before reading that you can design it. We'll see if he says yes or no. Also, how does this amp sound like? Detailed and warm?
Struth, i already sent him a pm asking him if he could do it just before reading that you can design it. We'll see if he says yes or no. Also, how does this amp sound like? Detailed and warm?
Hi Guys
As I've stated before in other threads, a properly designed amp has little or no sound of its own.
Many people have never heard accurate sound, and when they do they perceive it as thin or lacking bass. If you need a bass boost, use an EQ,
Have fun
Kevin O'Connor
As I've stated before in other threads, a properly designed amp has little or no sound of its own.
Many people have never heard accurate sound, and when they do they perceive it as thin or lacking bass. If you need a bass boost, use an EQ,
Have fun
Kevin O'Connor
brlmat,
Been following this thread, but can't recall where you are in your project, or if you've decided/selected an amp design yet, but I thought I would throw another idea into the mix for you. 😀 If you truly need 250wpc, then this may not be what you're looking for, but give this amp module a look-see.
It is assembled, so that may take some of the fun out of the project, but it also means it will likely work the first time, provided no problems with the PSU. I guess it comes down to where you would rather start your project - from scratch with PCBs, or a module. Going this route may cut-down on the frustration level of your post build troubleshooting should you decide on a bare-bones approach. 🙂
Rick
Been following this thread, but can't recall where you are in your project, or if you've decided/selected an amp design yet, but I thought I would throw another idea into the mix for you. 😀 If you truly need 250wpc, then this may not be what you're looking for, but give this amp module a look-see.
It is assembled, so that may take some of the fun out of the project, but it also means it will likely work the first time, provided no problems with the PSU. I guess it comes down to where you would rather start your project - from scratch with PCBs, or a module. Going this route may cut-down on the frustration level of your post build troubleshooting should you decide on a bare-bones approach. 🙂
Rick
Hi Guys
That LME module is 100W/ch at 8R. The caps supplied are 63V. It's cool that the heat sink is included.
A reasonable value for someone on a budget who wants to do some wiring, but better performance is available at that power level if you buy the Signal Transfer Co. kits. Yes, more $$ but much lower THD. You could also scratch build a better amp for similar money to the LME.
If you eliminated the passive crossovers in your speaker cabinets and went active and biamped, then the LMEs might be reasonable. Distribute more power over the various bands and only require limiting for the woofers, where noise or any possible distortions won't be an issue.
Have fun
Kevin O'Connor
That LME module is 100W/ch at 8R. The caps supplied are 63V. It's cool that the heat sink is included.
A reasonable value for someone on a budget who wants to do some wiring, but better performance is available at that power level if you buy the Signal Transfer Co. kits. Yes, more $$ but much lower THD. You could also scratch build a better amp for similar money to the LME.
If you eliminated the passive crossovers in your speaker cabinets and went active and biamped, then the LMEs might be reasonable. Distribute more power over the various bands and only require limiting for the woofers, where noise or any possible distortions won't be an issue.
Have fun
Kevin O'Connor
redjr, i appreciate your help. I settled to the blameless schematic our dear Struth posted as i only have to build the amp boards and some protections (such as DC, temp etc).
brimat, are you making your own PCB's? If so, would you mind sharing the artwork once you have it. I am interested in that amp as well.
Thanks, Terry
Thanks, Terry
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