True Complementary TO220 MOSFETs
Fairchild appears to have a true complementary pair :
http://www.diyaudio.com/forums/pass-labs/271926-f5-headamp-4.html#post4363293
Patrick
Fairchild appears to have a true complementary pair :
http://www.diyaudio.com/forums/pass-labs/271926-f5-headamp-4.html#post4363293
Patrick
Vacuphile, I never said each and every one, I meant the whole. Make the whole work as a coherent whole, not a sum of bits and parts.
This also assumes that the designer has the power of choice, of selecting each device for its optimal perfomance in doing the job it's supposed to do. Like using a specific part where he knows it will do well through experience. This is obviously a matter of engineering. he won't be choosing parts according to their case colour.
The same goes in selecting best bias for the job, one circuit at a time, polishing it as it were. I have been in situations where the math said a bias of say 2 mA should be just fine, yet it sounds better if the bias is say 4 mA. Since you can't just double something without consequence, this also means making it work well with the rest. Personally, I like to run power amps "hot", using more bias than is usual, I try not to go overboard, but in my experience, "hot" running amps tend to sound better, more effortless.
This choice also extends to being able to use some more exotic schemes, such as doubling the VAS transostors, i.e. using two in parallel instead of just one. I find this tends to widen the opan loop bandwidth, nosting spectacular, but it is there. Ditto for cascoding. So, piece by piece, you have much room to choose from, unless your accountant is standing right behind you and is having a heart attack every time you add a device, and/or choose a more expensive device.
Hi Jan,
I just split one long thread into two pieces to keep the size down. But, I noticed that John talks about far more than this one product. It would seem fitting to allow John and company to discuss these things in a free atmosphere that remains more on point than this one did. The moderating team could then cover the new thread more diligently to keep the grass cut as it were.
There should be a place where more experienced designers can exchange ideas freely without being bogged down in off topic rants and disagreements. Keeping the discussion on a more professional level might be far more satisfying to the professional and gifted.
Just an idea after watching this thread rumble along. Any other suggestions from anyone?
-Chris
I just split one long thread into two pieces to keep the size down. But, I noticed that John talks about far more than this one product. It would seem fitting to allow John and company to discuss these things in a free atmosphere that remains more on point than this one did. The moderating team could then cover the new thread more diligently to keep the grass cut as it were.
There should be a place where more experienced designers can exchange ideas freely without being bogged down in off topic rants and disagreements. Keeping the discussion on a more professional level might be far more satisfying to the professional and gifted.
Just an idea after watching this thread rumble along. Any other suggestions from anyone?
-Chris
Chris,
What's wrong with this thread?? And why do you think any other tread with the same subjects and suspects would be different??
I suggest you try to re-close this can of worms very quickly ;-)
Jan
All three article issues are downloadable from linearaudio.nl. They are even in English ;-
Hi dvv,
The Marantz 170DC / 300DC were very close. The 300DC used separate regulated power supplies for the voltage amplification stage, per channel as well. That makes 4 completely separate supplies. This shows up as an improvement when you have higher AC mains noise, or running at high power. I have rebuilt a few 170DC amplifiers, as well as the larger 300DC. I am lucky enough to own a 300DC, and it does sound better than the 170DC after both have been gone over.
These all share a diamond buffer output stage. Nakamichi made a 620 amp that shared that overall type of circuit. Many other amplifiers out there did the same, and they all have those qualities that you like in your 170DC. If I stumbled onto a 170DC, I would rebuild it and use it in my bedroom system. They are really effortless sounding with extremely clear high notes.
-Chris
The Marantz 170DC / 300DC were very close. The 300DC used separate regulated power supplies for the voltage amplification stage, per channel as well. That makes 4 completely separate supplies. This shows up as an improvement when you have higher AC mains noise, or running at high power. I have rebuilt a few 170DC amplifiers, as well as the larger 300DC. I am lucky enough to own a 300DC, and it does sound better than the 170DC after both have been gone over.
These all share a diamond buffer output stage. Nakamichi made a 620 amp that shared that overall type of circuit. Many other amplifiers out there did the same, and they all have those qualities that you like in your 170DC. If I stumbled onto a 170DC, I would rebuild it and use it in my bedroom system. They are really effortless sounding with extremely clear high notes.
-Chris
Thanks for the pointer, Chris.
I probably never missed the regulated stages because I run all my audio gear by default through a mains filter of my own construction, and that does take much of the muck out before it even enters the amp's PSU.
Given the relatively high sensitivuty of my main speakers, 92 dB/2.83V/1m in smallish rooms (none bigger than 13.2*11.6 ft, I rarely use a lot of power, mostly when I'm alone and go for some thunder and brimstone. Even so, my 'scope says I rarely peak above 78W/8 Ohms worst case, and this is well within the 170DC's grasp, especially with the new big electrolytics.
Also, I have had no more than a brush with the 300DC, so I don't know it well and therefore cannot compare the two. I'll just take your word for it.
I probably never missed the regulated stages because I run all my audio gear by default through a mains filter of my own construction, and that does take much of the muck out before it even enters the amp's PSU.
Given the relatively high sensitivuty of my main speakers, 92 dB/2.83V/1m in smallish rooms (none bigger than 13.2*11.6 ft, I rarely use a lot of power, mostly when I'm alone and go for some thunder and brimstone. Even so, my 'scope says I rarely peak above 78W/8 Ohms worst case, and this is well within the 170DC's grasp, especially with the new big electrolytics.
Also, I have had no more than a brush with the 300DC, so I don't know it well and therefore cannot compare the two. I'll just take your word for it.
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Yes. Create a thread, or even a separate forum, and give Mr. Curl moderation powers. Make sure everybody is aware of this. Mr. Curl could then root out anything he considers as off topic, offending, or simply inconvenient.
Hi everybody, nice of you to think of me. I am not in a position to really argue with anyone here. However, that does not mean that I find it useful to attempt to contribute either.
It's true, most of my best efforts and design breakthroughs happened 40 or so years ago. Now, I have only the added wisdom of making many different designs and their acceptance in the audio marketplace to the equation. Unfortunately, many disagree with me as to what is important in audio circuit design, so we get nowhere. I'll just sit back and collect the links that I do find really valuable. If I can answer a question, then I will have something to respond to.
I haven't retired, I am working on new audio products for 3 different companies. Wait till next year for them.
It's true, most of my best efforts and design breakthroughs happened 40 or so years ago. Now, I have only the added wisdom of making many different designs and their acceptance in the audio marketplace to the equation. Unfortunately, many disagree with me as to what is important in audio circuit design, so we get nowhere. I'll just sit back and collect the links that I do find really valuable. If I can answer a question, then I will have something to respond to.
I haven't retired, I am working on new audio products for 3 different companies. Wait till next year for them.
Hi John,
I was reflecting over the last number of years with this thread. I think it comes down to you being free to express yourself without being bullied. I really do think that allowing you to discuss these things in an abstract sense avoids calls for disclosure. You would probably have an easier time with things.
John, if you think this might work, I am willing to try and maintain order. I'm sure other moderators would also be on board with this. You might enjoy a change in how discussions go if disruptive posts are reduced or eliminated.
-Chris
I was reflecting over the last number of years with this thread. I think it comes down to you being free to express yourself without being bullied. I really do think that allowing you to discuss these things in an abstract sense avoids calls for disclosure. You would probably have an easier time with things.
John, if you think this might work, I am willing to try and maintain order. I'm sure other moderators would also be on board with this. You might enjoy a change in how discussions go if disruptive posts are reduced or eliminated.
-Chris
Hi dvv,
The 170DC comes very, very close to the 300DC sonically. I perform the same work to either amplifier, plus looking after the extra power supply circuitry in the 300DC. They are the same circuit otherwise. Both are very enjoyable to listen to once parts are matched and some changed to other types. So far, the best amplifiers I have heard.
-Chris
The 170DC comes very, very close to the 300DC sonically. I perform the same work to either amplifier, plus looking after the extra power supply circuitry in the 300DC. They are the same circuit otherwise. Both are very enjoyable to listen to once parts are matched and some changed to other types. So far, the best amplifiers I have heard.
-Chris
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These look remarkably good for first-order matching, if the datasheets are accurate. As remarked in the referenced thread, I think the key is the P channel's lower breakdown voltage compared to the N device's.
FQP3N30, FQP3P20. Fairly small chips in TO-220 packages.
+1000
anatech, I also have a suggestion for the new thread (if you decide to create it) - please dissalow certain unproductive type of posts/ words used there, i.e. the ones that create endless pointless back and forth arguments, flame wars, trolling and drives away readers/contributors. 'Double blind' and 'bybee' comes to mind..
Anyone mentions these - off you go to the sin bin.
Best,
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John,
In the past you have talked about using particular devices for your designs that are based on devices that you have collected large amounts of that are no longer available to most. How does this affect your designs when a company wants to use what is currently available commodity components, do you find you have to change your thinking when you can't use your favorite devices or is this just a simple inconvenience to your design thoughts?
In the past you have talked about using particular devices for your designs that are based on devices that you have collected large amounts of that are no longer available to most. How does this affect your designs when a company wants to use what is currently available commodity components, do you find you have to change your thinking when you can't use your favorite devices or is this just a simple inconvenience to your design thoughts?
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