When you set the bias, rember that you need to set it using the actual power supply that will be utilized. If you set it for lower rails using the variac, it will be too high when you finally connect the real PS. I mention this in case you are familiar with the bias setting procedure on a BJT amp.
Thanks so much both of you.
I think I understand it well now. I will try and test it this week. My heatsinks won't be here for a while. I do have some others that I could probably use to set the bias. I won't have to run them hard for that.
The heatsinks are going to determine how big my case is so I can't really build it until they are here.
I had to order the little PCB fuse clips again. The first two ltime I ordered them I got it wrong. I thinks I ordered them right this time. The shipping on my mistakes is killing me. I can see why folks like to buy complete kits.
Ah well, I learning a lot and enjoying getting to know you folks so it's all good.🙂
Blessings, Terry
I think I understand it well now. I will try and test it this week. My heatsinks won't be here for a while. I do have some others that I could probably use to set the bias. I won't have to run them hard for that.
The heatsinks are going to determine how big my case is so I can't really build it until they are here.
I had to order the little PCB fuse clips again. The first two ltime I ordered them I got it wrong. I thinks I ordered them right this time. The shipping on my mistakes is killing me. I can see why folks like to buy complete kits.
Ah well, I learning a lot and enjoying getting to know you folks so it's all good.🙂
Blessings, Terry
np Terry
Just an update on my project, i took it round to a friends place and hooked it up to his JAMO D590s , 4 ohm
quite difficult speakers to drive with 2x 5" midbass +tweeter, and an 8|" woofer int he base, totalling 4ohm nom
it ran them with ease, he was quite impressed and wanted to know how much for one hehe , especially after having heard them run on a 2grand amp (dont know what sort exactly)
i did notice driving these speakers at quite high volumes the amp ran pretty hot with these sinks, thankfully the rest of the enclosure started doing some heatsinking and the whole thing got warm,
about the only thing I have issues with so far is the amps noise level , hiss is more than i would like, noticably more than the very quiet Gainclone i have here.
this is not a real issue as i can't hear any hiss from listening position but i am fussy with such things.
very eager to know how u get on terry, if u have highish levels of noise aswell we may be able to work out a way around it. im throwing in some more BG caps but i doubt they will help.
cheers.
Just an update on my project, i took it round to a friends place and hooked it up to his JAMO D590s , 4 ohm
quite difficult speakers to drive with 2x 5" midbass +tweeter, and an 8|" woofer int he base, totalling 4ohm nom
it ran them with ease, he was quite impressed and wanted to know how much for one hehe , especially after having heard them run on a 2grand amp (dont know what sort exactly)
i did notice driving these speakers at quite high volumes the amp ran pretty hot with these sinks, thankfully the rest of the enclosure started doing some heatsinking and the whole thing got warm,
about the only thing I have issues with so far is the amps noise level , hiss is more than i would like, noticably more than the very quiet Gainclone i have here.
this is not a real issue as i can't hear any hiss from listening position but i am fussy with such things.
very eager to know how u get on terry, if u have highish levels of noise aswell we may be able to work out a way around it. im throwing in some more BG caps but i doubt they will help.
cheers.
Terry,
This is why DIY'ers have a stock of thingies around, and try to explain our spouses, that these odd bits are handy for future projects. I don't know anyone who hasn't ordered the wrong parts, and tried to cut corners (build- and money-wise), ending up with bigger investments in the end. Oh, well... it's all part of the fun (or so they say... 😀 ).
Jennice
This is why DIY'ers have a stock of thingies around, and try to explain our spouses, that these odd bits are handy for future projects. I don't know anyone who hasn't ordered the wrong parts, and tried to cut corners (build- and money-wise), ending up with bigger investments in the end. Oh, well... it's all part of the fun (or so they say... 😀 ).
Jennice
Hi mAJORD,
Yes i'm looking forward to hearing what mine will sound like. Hoping for no hiss of course.
Hi Jens,
Yes, it seems I'm well on my way to future projects. 😀
As can be seen by the other thread I started looking for an amp design that can utilize the too big transformer I bought for this project.
My wife bought me a drawered cabinet to store all the stuff I've bought that can't be used yet.
Blessings, Terry
Yes i'm looking forward to hearing what mine will sound like. Hoping for no hiss of course.
Hi Jens,
Yes, it seems I'm well on my way to future projects.
😀 As can be seen by the other thread I started looking for an amp design that can utilize the too big transformer I bought for this project.
My wife bought me a drawered cabinet to store all the stuff I've bought that can't be used yet.
Blessings, Terry
Hi terry,
Is your wife understanding or tired of you? 😀
I haven't noticed your new thread. What's it?
Jennice
Is your wife understanding or tired of you? 😀
I haven't noticed your new thread. What's it?
Jennice
Well I hope she's not tired of me. 😱
No, it was a Christmas present. One of those little cabinets with the plastic see through drawers.
The other thread is here.
I received my heatsinks last night so I will be building my chassis this week.
I did some testing lastnight. I used the 5watt 100ohm "safety" resistors that Rod suggests and my variac to set the PSU at +/-15v rails. I'm supposed to measure 2V across the resistors but I only read between .225v and .255v across them on each of the three boards. Any ideas why and what to look for?
Any help will be greatly appreciated.
Thanks Terry
No, it was a Christmas present. One of those little cabinets with the plastic see through drawers.
The other thread is here.
I received my heatsinks last night so I will be building my chassis this week.
I did some testing lastnight. I used the 5watt 100ohm "safety" resistors that Rod suggests and my variac to set the PSU at +/-15v rails. I'm supposed to measure 2V across the resistors but I only read between .225v and .255v across them on each of the three boards. Any ideas why and what to look for?
Any help will be greatly appreciated.
Thanks Terry
Terry:
i was getting similar voltages (more like 0.5) across my boards on 15v supply, i wouldnt be to concerned yet, better lower than higher.
see if u can make the voltage increase as u wind up the pots slowly.
check for 0v on the output , and then ur set to try it out for any glaringly obvious distortion, with a source
dont forget to check the input temrinals for unwanted voltage too just incase.
I found when i later applied the full rail voltage, on min bias setting i got closer to the 2v across the resistors , tho 1 side IS still different, i dont know why (i think it was 1v at min setting)
i was getting similar voltages (more like 0.5) across my boards on 15v supply, i wouldnt be to concerned yet, better lower than higher.
see if u can make the voltage increase as u wind up the pots slowly.
check for 0v on the output , and then ur set to try it out for any glaringly obvious distortion, with a source
dont forget to check the input temrinals for unwanted voltage too just incase.
I found when i later applied the full rail voltage, on min bias setting i got closer to the 2v across the resistors , tho 1 side IS still different, i dont know why (i think it was 1v at min setting)
mAJORD said:
Thanks, I'll check those things when I get home, especially the output and input voltage. I don't have them mounted to the heatsinks yet. Hopefully tonight.
Thanks again, Terry
Ok, at full voltage they measured .650v so I set it to 2.65v. All three were about the same, but the - rail and the + rails read a little differently. Something like .650v and .730v.
All three board had this same differential. Hope that's OK.
Still waiting on a few parts so I will have to wait to hear it until next week.
Blessings, Terry
All three board had this same differential. Hope that's OK.
Still waiting on a few parts so I will have to wait to hear it until next week.
Blessings, Terry
Terry,
I wouldn't set the bias while working on the limited supply. I suggest you turn it down to minimum, and wait with this final adjustment until you're at full operational voltage.
Speaking of parts...
I've been working on my own project during this holiday (my understanding g/f is happy when I pop out from my electronics room for a meal ), and have (hopefully) only the last wire-work to do before it's done. (the first of two identical ones).
I'll upload a progress image when I get around to actually take one...
The wire work has taken much longer than I ever imagined it to. *sigh* With any luck it'll be completed in the early hours of the 31st, so it'll play for new years eve. We'll be at my parents, near by, so we don't have any preparations to do ourselves. *horay*
Contrary to the recent one, these will have fuses between the PSU and the power stage. Ideally these should never blow, so I mounted them a little aside, as access to them isn't first priority for user friendliness. However, now that it's all (-most) wired up, I have a hard time fiddeling my fingers into the corners to actually mount the fuses in their clamps. *DOH!*
Oh, well.. only wasted about half an hour and a fingernail to get them into position.
Jennice
I wouldn't set the bias while working on the limited supply. I suggest you turn it down to minimum, and wait with this final adjustment until you're at full operational voltage.
Speaking of parts...
I've been working on my own project during this holiday (my understanding g/f is happy when I pop out from my electronics room for a meal
), and have (hopefully) only the last wire-work to do before it's done. (the first of two identical ones).I'll upload a progress image when I get around to actually take one...
The wire work has taken much longer than I ever imagined it to. *sigh* With any luck it'll be completed in the early hours of the 31st, so it'll play for new years eve. We'll be at my parents, near by, so we don't have any preparations to do ourselves. *horay*
Contrary to the recent one, these will have fuses between the PSU and the power stage. Ideally these should never blow, so I mounted them a little aside, as access to them isn't first priority for user friendliness. However, now that it's all (-most) wired up, I have a hard time fiddeling my fingers into the corners to actually mount the fuses in their clamps. *DOH!*
Oh, well.. only wasted about half an hour and a fingernail to get them into position.
Jennice
Actually, I did run it up to full operational voltage before I set the bias. I believe that I have to have the resistors in place to set the bias so this seemed like the best time to do that.
Anyway, I suppose I can do it again once everything is put together if I need to.
Looking forward to the pics of your stuff too.
I guess I should take some pics of my stuff before I get it all together. Might help someone else some day.
I hope your system sounds great on New Years Eve.
Blessings, Terry
Jennice, took me longer to do the wiring than loading both boards , goodluck getting it making noises for NYE 😀
Terry, sounds promising!
, goodluck getting it making noises for NYE 😀Terry, sounds promising!
Dummy load
Jennice,
"Personally I haven't found high power dummy loads I'd wanted to invest in, so I've used a couple of wire-wound 7W resistors in parallel, which I put into a glass of water."
I've seen this resistors in water quoted before.
How do you actualy do it.
My consern would be shorting the resitors out and blowing the amp!
Jennice,
"Personally I haven't found high power dummy loads I'd wanted to invest in, so I've used a couple of wire-wound 7W resistors in parallel, which I put into a glass of water."
I've seen this resistors in water quoted before.
How do you actualy do it.
My consern would be shorting the resitors out and blowing the amp!
Distortion
Hi all,
There seem to be a number of people who have built and understand the ESP 3A amp.
I have just completed building the 3A amp but have problems with distortion at low volume levels the distortion seem much less at high volume this could be due to masking of the louder notes.
The amp has great potential.
The amp passed all the set-up tests and is running in the class AB set-up eg 94mv bias setting.
35v + and – rails.
Let me say there is no fault with the amp design or board supplied, any error is down to me somewhere in my construction.
The board is a beautiful piece of work and the construction notes cover all aspects that a novice needs.
I just wondered if any of you had a similar problem caused by some construction error.
Hi all,
There seem to be a number of people who have built and understand the ESP 3A amp.
I have just completed building the 3A amp but have problems with distortion at low volume levels the distortion seem much less at high volume this could be due to masking of the louder notes.
The amp has great potential.
The amp passed all the set-up tests and is running in the class AB set-up eg 94mv bias setting.
35v + and – rails.
Let me say there is no fault with the amp design or board supplied, any error is down to me somewhere in my construction.
The board is a beautiful piece of work and the construction notes cover all aspects that a novice needs.
I just wondered if any of you had a similar problem caused by some construction error.
thehuntshunt:
the resiters cant blow up , they are wirewound, and when dunked in the water are cooled sufficiently to withstand the power without melting the wire inside.
u do get nasty buildups on the immersed wires from the current flowing thru the water cuasing electrolysis , eventually cuasing them to break. thats all tho.
sorryt ot hear about ur problems with the p3, i dont have any ideas not having a good understanding of indepth symptoms. but first things first do u have 1 or 2 amp boards? if 2 , are they both giving the same problem?
the resiters cant blow up , they are wirewound, and when dunked in the water are cooled sufficiently to withstand the power without melting the wire inside.
u do get nasty buildups on the immersed wires from the current flowing thru the water cuasing electrolysis , eventually cuasing them to break. thats all tho.
sorryt ot hear about ur problems with the p3, i dont have any ideas not having a good understanding of indepth symptoms. but first things first do u have 1 or 2 amp boards? if 2 , are they both giving the same problem?
Hitsware,
What's the schematic for???
HuntTheShunt,
Nice name you found there. Not overwhelmingly optimistic on yourself, but nice nonetheless.
The resistor thing is really totally simple. Just take the resistors, and put them into normal water. You can lower the ammunt of build-up bu using de-mineralized water, but the mis-colouration from extensive heat on the resistors is not likely to be avoided. Especially not if you - like me - forget how fast the water boils away if testing a high power amplifier, and get reminded when you start to smell the laquer coating on the resiators.
As long as you don't work with really high voltages, or really dirty water, you should have no problems with short-circuiting in the water.
H.T.S. and mAJORD,
I am not likely to belive the buildup to be electrolytically related, as it's (hopefully) AC signal sources you're testing with. Thus, the elevctrolytic process should be reversed with the phase of the input signal, and hence there should be no problem. I'm more likely to belive it to be minerals from the water, like the residues when boiling water in a kettle (the normal way 😉 ).
As for tracking errors on your amp, I am afraid that I cannot help, as I haven't build that project. What does Rod Elliot (the ESP guy) have to say to it?
Jennice
What's the schematic for???
HuntTheShunt,
Nice name you found there. Not overwhelmingly optimistic on yourself, but nice nonetheless.
The resistor thing is really totally simple. Just take the resistors, and put them into normal water. You can lower the ammunt of build-up bu using de-mineralized water, but the mis-colouration from extensive heat on the resistors is not likely to be avoided. Especially not if you - like me - forget how fast the water boils away if testing a high power amplifier, and get reminded when you start to smell the laquer coating on the resiators.
As long as you don't work with really high voltages, or really dirty water, you should have no problems with short-circuiting in the water.
H.T.S. and mAJORD,
I am not likely to belive the buildup to be electrolytically related, as it's (hopefully) AC signal sources you're testing with. Thus, the elevctrolytic process should be reversed with the phase of the input signal, and hence there should be no problem. I'm more likely to belive it to be minerals from the water, like the residues when boiling water in a kettle (the normal way 😉 ).
As for tracking errors on your amp, I am afraid that I cannot help, as I haven't build that project. What does Rod Elliot (the ESP guy) have to say to it?
Jennice
Jennice,
So as long as the insulation on the wires attached to the end of a bunch resistors is ok and does not melt at boiling point it is there is no short circuit.
“What does Rod Elliot (the ESP guy) have to say to it?”
Rod is very helpful and is helping me resolve the problem.
I just wondered if there was any one who had similar issues due to a dumb move on the constructor’s part.
Hitsware,
Looks like a long tailed pair of mosfets and a pair of mosfet drivers.
Have you built it?
If so what does it sound like?
What kind of mosfets are they?
What voltage?
What is the only caps value 10uF, pF ,nF
Where is the output connected?
And on and on… 😉
So as long as the insulation on the wires attached to the end of a bunch resistors is ok and does not melt at boiling point it is there is no short circuit.
“What does Rod Elliot (the ESP guy) have to say to it?”
Rod is very helpful and is helping me resolve the problem.
I just wondered if there was any one who had similar issues due to a dumb move on the constructor’s part.
Hitsware,
Looks like a long tailed pair of mosfets and a pair of mosfet drivers.
Have you built it?
If so what does it sound like?
What kind of mosfets are they?
What voltage?
What is the only caps value 10uF, pF ,nF
Where is the output connected?
And on and on… 😉
Ok, folks... *drum roll, please...*
The first stereo amp actually got finished to play on Dec.31st, in the early afternoon!
One channel runs a little warmer than the other (haven't managed to get the bias identical), but I'm very pleased with the sound.
New pic's can be seen on my ftp server. The heat sinks (2 per ch. at 0.6 K/W each aren't exactly overkill) but it seems ok. With the original bias setting, one channel had a slowly, but (seemingly) never-ending idle current, but lowering the set-point for the bias solved this. (Or so it seems from my tests until now.) Strange, as the bias transistor should do the job regardless of set-point. 😕
The voltage amplifier stage runs kinda hot (60 deg. delcius) with TO220 housing transistors, but it drives the driver/output transistors with a slam.
Even better, it seems very quiet (when it's supposed to), and jumps to life even scarier than the old 80W/h I made. (The new one is standing on top of the old 4-channel one on the pics).
I'll watch it some time for potential thermal runaway, but that's my only concern right now.
However, it's all takem MUCH longer than expected, so I guess I better be a little social in the start of 2005, and not isolate myself from the real world for a while. I'm starting to wonder when I'll get around to build the second set of these new "twins". Oh, well... time will tell.
Jennice
The first stereo amp actually got finished to play on Dec.31st, in the early afternoon!
One channel runs a little warmer than the other (haven't managed to get the bias identical), but I'm very pleased with the sound.
New pic's can be seen on my ftp server. The heat sinks (2 per ch. at 0.6 K/W each aren't exactly overkill) but it seems ok. With the original bias setting, one channel had a slowly, but (seemingly) never-ending idle current, but lowering the set-point for the bias solved this. (Or so it seems from my tests until now.) Strange, as the bias transistor should do the job regardless of set-point. 😕
The voltage amplifier stage runs kinda hot (60 deg. delcius) with TO220 housing transistors, but it drives the driver/output transistors with a slam.
Even better, it seems very quiet (when it's supposed to), and jumps to life even scarier than the old 80W/h I made. (The new one is standing on top of the old 4-channel one on the pics).
I'll watch it some time for potential thermal runaway, but that's my only concern right now.
However, it's all takem MUCH longer than expected, so I guess I better be a little social in the start of 2005, and not isolate myself from the real world for a while. I'm starting to wonder when I'll get around to build the second set of these new "twins". Oh, well... time will tell.
Jennice
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