keantoken said:Thank you for being helpful Daniel.
However I'm sure those amps Ostripper posted still simulate quite well without any additions. As far as lower distortion at high power levels, I might say that it is worth using this new current mirror.
It all depends on whether you think this discussion will help you reach your goal. We could move the discussion to a new thread, if you want.
I just don't want to be wasting your time.
- keantoken
There's no waste of time. This discussion has been very helpful indeed.
ostripper said:
Two buckets of 63v electrolytic caps, many varieties of rectifier, two boxes of polyester caps, two boxes of ceramic caps and about 1.5 cubic feet of resistors.
The antek 5236 looks good to me, with two of 36vac. I believe that I'll use it with some nifty options and come out with 51vdc rails or slightly lower.
That is within tolerances for the 63v caps I have on hand if/when they are used pin-to-pin with the 0v at centerpoint. I shouldn't use higher voltage rails unless I purchase higher voltage caps. The same caveats apply as when batteries are connected in series. . . and then recharged. Some go slightly over, some go slightly under. So, it takes a bit of extra tolerances in order to have the caps last.
The cost of the power supply is approximately $8. This, I think is good for a frugal amp. In my case, yes I already have the parts.
keantoken said:Well, it's 12:30 in my part of the 'states so I must be getting to bed.
Don't y'all go too far without me.
- keantoken
. . . off to bed, while visions of transistors danced in his head. . .
Up on the rooftop Reindeer charge,
Yes, they've got your Mastercard,
Filling the chimney with lots of toys,
All for the little one's Christmas noise. . .
Okay, I better go to bed before I post something really nuts.
Fig60 looks like an active load that is driven in anti-phase to the current passing Tr1.
The effect is similar to a mirror. But I would never call that a mirror.
The characteristics of the diode and transistor are probably too different to be well matched and the two resistors in figure13 show that some level of adjustment has been used to try to get a match at the operating current.
If a pair of matched transistors were in place as the loads on the collectors and one of the transistors is diode connected, then adding the matched resistors to the emitters does create a mirror. This real mirror operates as an active load and increases the effective gain of the LTP input stage. The outcome is very similar.
One circuit uses a mirror, fig13 does not.
The effect is similar to a mirror. But I would never call that a mirror.
The characteristics of the diode and transistor are probably too different to be well matched and the two resistors in figure13 show that some level of adjustment has been used to try to get a match at the operating current.
If a pair of matched transistors were in place as the loads on the collectors and one of the transistors is diode connected, then adding the matched resistors to the emitters does create a mirror. This real mirror operates as an active load and increases the effective gain of the LTP input stage. The outcome is very similar.
One circuit uses a mirror, fig13 does not.
Andrew, you should look again its definetly a current mirror.
Simmed my amp at high power, and confirm MJL21193 s results, the distortion is lower although I dont get as great distortion decrease, about same as at low power.
I dug up my notes of when I designed this amp and noted down that that one gets thd reduction due to higher output impedance of the circuit and bonus was that currents when used in a ltp vas could be exactly matched by manupulating the resistor after the diode. So I simmed this, and can confirm the matching, this brings about another small reduction in distortion.
Yikes Im getting old, did things back then which Im forgetting exactly why I did them. The module I have with me was made in 1995 and I can see Ive been slipping up with the newer modules, although the difference is very small. Adjustment of just 4 ohms did the matching although this is dependant on transistor parameteres. I have kept using the exact trannies as of back then.
Clipping performance I find exactly the same as the mirror, but this Ill have to look at through a scope as I ve found discripencies between simulator and real world circuits before.
Keantoken, the polarity of your cfp is reversed, guess its the reason you are having problems.
Simmed my amp at high power, and confirm MJL21193 s results, the distortion is lower although I dont get as great distortion decrease, about same as at low power.
I dug up my notes of when I designed this amp and noted down that that one gets thd reduction due to higher output impedance of the circuit and bonus was that currents when used in a ltp vas could be exactly matched by manupulating the resistor after the diode. So I simmed this, and can confirm the matching, this brings about another small reduction in distortion.
Yikes Im getting old,
did things back then which Im forgetting exactly why I did them. The module I have with me was made in 1995 and I can see Ive been slipping up with the newer modules, although the difference is very small. Adjustment of just 4 ohms did the matching although this is dependant on transistor parameteres. I have kept using the exact trannies as of back then.Clipping performance I find exactly the same as the mirror, but this Ill have to look at through a scope as I ve found discripencies between simulator and real world circuits before.
Keantoken, the polarity of your cfp is reversed, guess its the reason you are having problems.
My story with On-Semi. . .
If I had a scope and the knowledge to use it, I would have found out that the MUR860 does indeed make noise, but rather up at a far higher pitch than a regular diode. The reason for my failure in applying this diode is that I couldn't snub the noise, having not realized its higher pitch. A scope would have shown this. The On-Semi part was working exactly as documented, and they were not at fault.
Ah, the power circuit study in relation to chip amps has been fascinating. And, speaking of noise, I've just received a pair of NTE's 1516 reproduction NEC uPC1212C tubefake op amp chips. I got one for the radio project, leaving an extra to play with. Clear output is about 1/4 watt although it will do 1.3 watts. So, what's a nice way to give one of these a boost from its 1/4w rating, up to 3 to 5 watts per an 8 ohm speaker? I'd like to try that with transistors just to study and experience a few more concepts.
If I had a scope and the knowledge to use it, I would have found out that the MUR860 does indeed make noise, but rather up at a far higher pitch than a regular diode. The reason for my failure in applying this diode is that I couldn't snub the noise, having not realized its higher pitch. A scope would have shown this. The On-Semi part was working exactly as documented, and they were not at fault.
Ah, the power circuit study in relation to chip amps has been fascinating. And, speaking of noise, I've just received a pair of NTE's 1516 reproduction NEC uPC1212C tubefake op amp chips. I got one for the radio project, leaving an extra to play with. Clear output is about 1/4 watt although it will do 1.3 watts. So, what's a nice way to give one of these a boost from its 1/4w rating, up to 3 to 5 watts per an 8 ohm speaker? I'd like to try that with transistors just to study and experience a few more concepts.
Hi keantoken, Ill get back to you soon, just having a small net problem at the moment. I have wireless system connected with my businesses and get continuously hacked, as soon as the cops leave Ill get the email out to you as well as answer about the vas, it was late last night when I looked at it.
homemodder said:
Hi HomeModder!
For that hacking business, select WPA + AES at your wireless. Delete favored access points from windows. Click your wireless from the list and enter the new password to reconnect, now securely.
EDIT: You might also wish to activate the "preferred access points only" selection in Windows.
While most wireless routers do have a the AES encryption option, some different language is used for WPA. It could be WPA Personal or WPA+WPA2.
If your wireless is not capable of WPA + AES, then WPA + TKIP + Un-Spell-Able password is an option. Choose a password that cannot pass the approval of a spell checker.
That can cover connectivity security decently and the wireless router's firewall probably catches most ingress, a major concern for business isn't covered. What about information exiting your network? I use Zone Alarm version 5.5 for my egress firewall. That turns the PC into the electronic version of a roach motel--they might get in, but they can't get out.
EDIT: This is great for the laptop as well. I hope this info helps.
The problem is not in my network, they get in from my connection from ISP, ISP provides high speed private wireless connection.
Ive used zone alarm, I have also seen some hacks go right through it. I have a special friend that seems to be able to go wherever he wants, the only way to stop him is by not being connected. He told me its actually easier through wire. With his help the cops have tracted this one too, he will be getting a big surprise in a couple of minutes when the cops knock on his door. Signal triangulators are nice tools to track someone down.
Ive used zone alarm, I have also seen some hacks go right through it
. I have a special friend that seems to be able to go wherever he wants, the only way to stop him is by not being connected. He told me its actually easier through wire. With his help the cops have tracted this one too, he will be getting a big surprise in a couple of minutes when the cops knock on his door. Signal triangulators are nice tools to track someone down.
homemodder said:The problem is not in my network, they get in from my connection from ISP, ISP provides high speed private wireless connection.
Ive used zone alarm, I have also seen some hacks go right through it
Unfortunately, that ISP is using such lousy security, its almost as bad as broadcasting your information in the clear. The ISP is at fault for negligence. If you can find an advertisement where the service is marketed as either private or secure, then the ISP is also at fault for fraud.
This might help encourage them spare the pocket change to update to a more modern security encryption algorithm.
Now this is more my territory
An ISP providing a high speed wireless connection is.. well IMO misadvertising. Wireless is not reliable in my experience. WPA2 + AES is the most secure but there are vectors of attack on the WPA2 protocol being worked on.
Best solution - get a wired connection and do your own wireless access point, and only if you must. If security is critical, you should stick to CAT5e with a good gateway between your LAN and the internet connection. Forget programs like ZoneAlarm. Personally, I use an old Pentium 3 with two network cards, and FreeBSD 7 configured to act as a firewall + router.
An ISP providing a high speed wireless connection is.. well IMO misadvertising. Wireless is not reliable in my experience. WPA2 + AES is the most secure but there are vectors of attack on the WPA2 protocol being worked on.
Best solution - get a wired connection and do your own wireless access point, and only if you must. If security is critical, you should stick to CAT5e with a good gateway between your LAN and the internet connection. Forget programs like ZoneAlarm. Personally, I use an old Pentium 3 with two network cards, and FreeBSD 7 configured to act as a firewall + router.
Well, you never know what I'll be thinking of, but right now its. . .
How do I do this sort of thing (in the photo) when the IC (in the photo) is limited to 9v?
The deal is, the ic output is 1w, but the best quality of that is the first 1/4w; however, I need 5w (half that would suffice). So. . . how to?
I've been studying this for quite a while, and it seems to be brilliantly simple to do if the IC were something like 10w BTL, but that is not the IC in question. Its a sound processor IC that is for driving a speaker. Its remarkable except that the output is insufficient. Um. . . help?
How do I do this sort of thing (in the photo) when the IC (in the photo) is limited to 9v?
The deal is, the ic output is 1w, but the best quality of that is the first 1/4w; however, I need 5w (half that would suffice). So. . . how to?
I've been studying this for quite a while, and it seems to be brilliantly simple to do if the IC were something like 10w BTL, but that is not the IC in question. Its a sound processor IC that is for driving a speaker. Its remarkable except that the output is insufficient. Um. . . help?
Attachments
You would have to have voltage gain in the output stage, ie a CFP, but that is just asking for trouble really.
For an example, see http://www.wnaudio.com/amos100.pdf - even though this shows MOSFETs the principle is the same. Be warned that when I tried to simulate this, I could not get it stable.
For an example, see http://www.wnaudio.com/amos100.pdf - even though this shows MOSFETs the principle is the same. Be warned that when I tried to simulate this, I could not get it stable.
Jaycee, its not misadvertising, I get download speeds of around 700kbs on average, during the night when there is less users Ive seen 1mbs. Very reliable, Im about 4 km from the antenna. Security is a problem though, the friend explained to me this morning how hackers go through WPA2 + AES, these people have nothing better to do. While browsing the net I found videos at some sites even explaining and showing how to do this. Anyway cops didnt catch anyone, signal coming from a park about km away from me.
ostripper said:
Hi OS!
This thread was wandering a bit, while awaiting some answers (and while I've been studying).
I do like the moderator's suggestion of building several amplifiers to see what I like. With a discrete amplifier comes the opportunity to also find out why exactly (quite the difference from a chipamp). That's exciting!!!!
One good option doesn't lead to that particular study, but two or more good options can do it.
For this, I'd love to build two of your amplifiers and one of John's amplifiers (the new one having the circuits like the original purpose of this thread).
Its not about who did a better amp.
Its is about studying what I hear versus the simulator. That's a tall order for me, but such a motivation will help me learn how to operate simulation software. And, its also a pretty good adventure.
The simulator will teach you a LOT about discrete design of you're clever enough to consider all possibilities for a given output. With an open mind, a lot can be gained. Beware, however, don't go putting 300W through a 2N3904.
I have very little real-world experience, as most of my experimenting has been done on the simulator. I've never had the money to do anything. In this case DIYAudio has provided a way for me to reality check my circuits, and to make sure I'm being practical while designing them. But on the side I have also received some criticism for this. Whatever you do, try not to annoy people TOO much.
I would say go for it, as working on the simulator can be a very worthwhile experience.
I would recommend LTSpice, from Linear Technologies. It's free, in the Design support section. There is also an active Yahoo Egroup for it where you can ask questions.
You can also write the output of your simulated circuit onto a .wav file for listening. Go to the help file and search for ".wav".
I can help you understand the sim, if you are interested in my assistance I can Email you so you'll have my Email address.
- keantoken
I have very little real-world experience, as most of my experimenting has been done on the simulator. I've never had the money to do anything. In this case DIYAudio has provided a way for me to reality check my circuits, and to make sure I'm being practical while designing them. But on the side I have also received some criticism for this. Whatever you do, try not to annoy people TOO much.
I would say go for it, as working on the simulator can be a very worthwhile experience.
I would recommend LTSpice, from Linear Technologies. It's free, in the Design support section. There is also an active Yahoo Egroup for it where you can ask questions.
You can also write the output of your simulated circuit onto a .wav file for listening.
Go to the help file and search for ".wav".I can help you understand the sim, if you are interested in my assistance I can Email you so you'll have my Email address.
- keantoken
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