Hi Peter,
A quick question. I've been running my amp in "test mode" for about a week now, meaning I have no lid on the chassis and I'm still waiting on heat sinks to complete the box. I've been operating the unit without heat-sinks but in good ventilation, and it works but if i turn the volume up too high, one or both of the channels cuts out completely. Is this clipping, or overheating? There's no distortion, just a cut-out that returns to normal after a few seconds, usually when I pull back on the volume a few clicks. Will heat sinks resolve this or is this the sharp clipping that I saw on the transformer voltages diagram when reaching a certain volume?
Many thanks
Lucas
A quick question. I've been running my amp in "test mode" for about a week now, meaning I have no lid on the chassis and I'm still waiting on heat sinks to complete the box. I've been operating the unit without heat-sinks but in good ventilation, and it works but if i turn the volume up too high, one or both of the channels cuts out completely. Is this clipping, or overheating? There's no distortion, just a cut-out that returns to normal after a few seconds, usually when I pull back on the volume a few clicks. Will heat sinks resolve this or is this the sharp clipping that I saw on the transformer voltages diagram when reaching a certain volume?
Many thanks
Lucas
Hi Lucas,
this is neither clipping nor overheating.
This is plain and simple operator abuse.
GET THE HEATSINKS FITTED!!!
this is neither clipping nor overheating.
This is plain and simple operator abuse.
GET THE HEATSINKS FITTED!!!
Peter,
Although I'm entirely happy with my current build, I'm curious to know what effects other capacitors might yield. For example, would Elna 1,000uf / 50v Silmics work in place of the Panasonic 1,500uf caps? Are there other substitutions you'd recommend trying? What value ranges are compatible (uf and v)? Or should I leave well-enough alone? (All I need is the slightest reason to order another kit, heh). Thanks!
David Barnett
SW Florida
Although I'm entirely happy with my current build, I'm curious to know what effects other capacitors might yield. For example, would Elna 1,000uf / 50v Silmics work in place of the Panasonic 1,500uf caps? Are there other substitutions you'd recommend trying? What value ranges are compatible (uf and v)? Or should I leave well-enough alone? (All I need is the slightest reason to order another kit, heh). Thanks!
David Barnett
SW Florida
ppapcro said:
Here it is: http://www.diyaudio.com/forums/showthread.php?s=&threadid=76609&highlight=
Vautrin said:
I didn't try Silmics with those amps, and Panasonic FCs were the second choice after BGs:
http://www.diyaudio.com/forums/showthread.php?postid=574431#post574431
http://www.diyaudio.com/forums/showthread.php?postid=581230#post581230
Thanks Peter, that's exactly what I meant. So, separate all the way. In this layout, with no common ground point, is there still a way to tie each board's signal ground to the chassis for shielding
purposes? A separate wire from each amp board OG to same point on chassis?
purposes? A separate wire from each amp board OG to same point on chassis?
A small ceramic cap in parallel to the disconnecting network achieves the HF coupling that is required for interference screening.
A ceramic cap from RCA barrel (return/ground) to the Chassis may achieve the same suppression.
A ceramic cap from RCA barrel (return/ground) to the Chassis may achieve the same suppression.
I've just finished preliminary project with Peter's boards.Everything is still on wooden board with no chassis.I've built dual mono bi-amp amplifier.On bass there's 2200uF Pana FC,on treble 100uF BG standard.I have a couple of questions.
About grounding.Do I have to connect every ground point on boards(SG,PG,OG,CHG...) in one point?I'm trying to built separate PS.
About pot.When I first tried amp with only two boards(simple stereo) 50k pot was ok.But now when i have two boards in parallel(on each channel) it's seems to much.I need to turn pot for about 70% to be very loud.I can turn it to 100% and listen(very,very loud),but I don't think that's 4x55W.For instance I've listened my other amp rated 45W at 8 ohms with 50k pot too,but I can't listen after 70% pot turn.It's too loud for me.What should I do?
Sorry if my English is not so good 🙂
About grounding.Do I have to connect every ground point on boards(SG,PG,OG,CHG...) in one point?I'm trying to built separate PS.
About pot.When I first tried amp with only two boards(simple stereo) 50k pot was ok.But now when i have two boards in parallel(on each channel) it's seems to much.I need to turn pot for about 70% to be very loud.I can turn it to 100% and listen(very,very loud),but I don't think that's 4x55W.For instance I've listened my other amp rated 45W at 8 ohms with 50k pot too,but I can't listen after 70% pot turn.It's too loud for me.What should I do?
Sorry if my English is not so good 🙂
Hi,
is one channel of the 50k pot feeding two parallel amplifiers?
What are the input filter values on each of the amplifiers?
i.e. both the low pass filter and the high pass filter.
Since they are Peter's chipamp implementation, can we assume there is no smoothing in the PSU? It's all done by the 2200uF & 100uF caps on the amp PCB.
is one channel of the 50k pot feeding two parallel amplifiers?
What are the input filter values on each of the amplifiers?
i.e. both the low pass filter and the high pass filter.
Since they are Peter's chipamp implementation, can we assume there is no smoothing in the PSU? It's all done by the 2200uF & 100uF caps on the amp PCB.
Yes,one channel of the pot is feeding two board of amps connected in parallel.
It's original Peter's amp(from his site).There's 10uF Pana FC on rect. boards.100uF and 2200uF is by the chip.
It's original Peter's amp(from his site).There's 10uF Pana FC on rect. boards.100uF and 2200uF is by the chip.
kele1975 said:
I assume it's only bi-amping, not active filtering?
The input impedance of the amp is set by R2=22k . If you connect two channels in parallel those resistors are also in parallel with combined impedance of 11K and that interacts with your pot in a different way than a single 22k; that's why different position on a volume for a given output level. However, as long as you have enough range, I wouldn't worry about that.
It's a common mistake that people asociate power output with position of a volume knob, it has nothing to do with it though. A potentiometer is simply an attenuator that adjust signal level fed to the amp, it does not affect the power of the amp.
Don't connect all grounds together. SG is connected with OG already on the board, CHG is optional ground point and normally does not need to ber used at all. If building separate PS (for each channel) simply connect boards as in picture here: http://www.diyaudio.com/forums/showthread.php?postid=1508956#post1508956
If using common supply for two channels, use grounding method explained here: http://www.diyaudio.com/forums/showthread.php?postid=1518369#post1518369
Thank you very much!
That was very fast reply.
Yes I'm using it in bi-amp configuration.I do realize that pot don't have anything with power of amp,but does it have anything with impurity of signal,for example between 10k and 50k pot?If I choose 10k,will it be too low value?
I don't follow first link.Amp boards are detached from rect boards.I want to build separate PS but in one box for both channels.That means two chassis.One for PS and another for amp.Connected with 4way XLR's.
Another thing,I'm using 25V toroids,but in real life that's 26V,so in finals I have 36V+36V on boards.Chips are running on cca 65-68 degrees Celsius.Is that to much?Will the voltage be lower if I don't use 10uF caps?
That was very fast reply.
Yes I'm using it in bi-amp configuration.I do realize that pot don't have anything with power of amp,but does it have anything with impurity of signal,for example between 10k and 50k pot?If I choose 10k,will it be too low value?
I don't follow first link.Amp boards are detached from rect boards.I want to build separate PS but in one box for both channels.That means two chassis.One for PS and another for amp.Connected with 4way XLR's.
Another thing,I'm using 25V toroids,but in real life that's 26V,so in finals I have 36V+36V on boards.Chips are running on cca 65-68 degrees Celsius.Is that to much?Will the voltage be lower if I don't use 10uF caps?
So you have 11K combined input shunt resistance, and by adding 50K pot it is still approx 8.5K. When you combine 11k with 10K pot, the impedance becomes approx 5K. It's up to your source if it can drive it, but 10K pot would be probably better.
When having PS in a separate box use the grounding method from a second link, you can check those pics for more info, as this is exactly what I do in Patek: http://www.audiosector.com/chassis_patek2_amp.shtml
The chips should not heat up that much, if they do, your heatsinks are probably not big enough (36V rails are perfectly fine)
When having PS in a separate box use the grounding method from a second link, you can check those pics for more info, as this is exactly what I do in Patek: http://www.audiosector.com/chassis_patek2_amp.shtml
The chips should not heat up that much, if they do, your heatsinks are probably not big enough (36V rails are perfectly fine)
Just to be clear.In that picture,one red is V+,the other one is V-,and two blacks is ground wire?
Heatsink is 125x10x40 mm copper bar for one channel,and I now it's not enough,but I'm planning to bond it to 10 mm Alu profile on chassis side.I hope that would be enough.
Heatsink is 125x10x40 mm copper bar for one channel,and I now it's not enough,but I'm planning to bond it to 10 mm Alu profile on chassis side.I hope that would be enough.
Yes, you are correct about wires.
Copper bar by itself is not good for heat dissipation: it will collect heat, but not release well. You need additional aluminum panels for that purpose.
Copper bar by itself is not good for heat dissipation: it will collect heat, but not release well. You need additional aluminum panels for that purpose.
Colin said:
Hi colin,
I about to start my first project. For my first project i am going to be using my current speakers that came with my Pioneer system. They are 6 Ohm. What secondary winding to you advise? and would the transformer you have detailed above be suitable?
Thanks
Dan
Thanks for the reply. I have been looking on your website reading up on the installation. you mention a good quality El transformer? are these better quality than the Torroid?