Hello diyers,
I wish to build a class A amp, and do not wish to buy/make PCBs. So I am contemplating making the Complementary Zen (zen v5), which can easily be point to point wired. Now the question:
I have 6 ohm speakers which I do not wish to replace. How well will this amp work with 6 ohm speakers? Will I need to lower the output impedence? How can I do this? Can I parallel output devices? How (details please)? Or do I really have to bridge two amplifiers?
Looking at the schematic included with this post, it seems I can easily parallel more output devices. However, I'm not sure which parts of the circuit need to be "doubled". I guessing I need to add another set of R9 & R10 and R11 & R12, but what else? It also seems I could get more power this way. What do you think. I'm pretty new to this so require answers in english not ampish
Your help is most appreciated.
Cheers.
The pic was removed. This is a link to the Complementary Zen article at the PassDIY site. See Figure 3.
I wish to build a class A amp, and do not wish to buy/make PCBs. So I am contemplating making the Complementary Zen (zen v5), which can easily be point to point wired. Now the question:
I have 6 ohm speakers which I do not wish to replace. How well will this amp work with 6 ohm speakers? Will I need to lower the output impedence? How can I do this? Can I parallel output devices? How (details please)? Or do I really have to bridge two amplifiers?
Looking at the schematic included with this post, it seems I can easily parallel more output devices. However, I'm not sure which parts of the circuit need to be "doubled". I guessing I need to add another set of R9 & R10 and R11 & R12, but what else? It also seems I could get more power this way. What do you think. I'm pretty new to this so require answers in english not ampish
Your help is most appreciated.
Cheers.
The pic was removed. This is a link to the Complementary Zen article at the PassDIY site. See Figure 3.
I think the Zen v5 is sufficient for 6 ohm load as it is, but if You want to add output devices the "doubbling" of mentioned resistors R7-12 is right, should be close tollerances (matched).
If You change Yor mind about PCB this layout works good:
Note that R numbers are not consistent with schematic, but easy enogh to see what´s what. R1 equals R9+R10
If You change Yor mind about PCB this layout works good:
Note that R numbers are not consistent with schematic, but easy enogh to see what´s what. R1 equals R9+R10
Attachments
More Qs + thanks
Thanks for the replies. Just wondering:
1. Do I need to halve R5 and R6 to provide more current to feed the additional fet gates?
2. So, does "doubling up" on the output devices halve the output impedence (and double the power if rail voltage and bias is the same - per device, but doubled in total, right)?
3. I assume I will need twice the power supply as well, assuming I use the same rail voltages and bias per device (but total bias current would be near 4 amps, or double original value). Seems it would be good to lower the rail voltage with the same bias value (per mosfet) to reduce the power dissipation of each device while still maintaining a decent output.
4. How do these amps sound anyway? Pretty good? (Just been reading about the DOZ amp, and heard some harsh words about them).
Thanks alot guys. Most helpful. Will post my proposed schematic in my next post.
Thanks for the replies. Just wondering:
1. Do I need to halve R5 and R6 to provide more current to feed the additional fet gates?
2. So, does "doubling up" on the output devices halve the output impedence (and double the power if rail voltage and bias is the same - per device, but doubled in total, right)?
3. I assume I will need twice the power supply as well, assuming I use the same rail voltages and bias per device (but total bias current would be near 4 amps, or double original value). Seems it would be good to lower the rail voltage with the same bias value (per mosfet) to reduce the power dissipation of each device while still maintaining a decent output.
4. How do these amps sound anyway? Pretty good? (Just been reading about the DOZ amp, and heard some harsh words about them).
Thanks alot guys. Most helpful. Will post my proposed schematic in my next post.
Re: Is this OK?
Only if your FETS are perfectly matched. Instead. connect 2 source resistors to each device's source pin, with no connection between the source pins. This will reduce the effects of transistor mismatching, but they still ought to be closely matched in pairs (IRFP240 to IRFP240, etc.)
You could use higher value source resistors for even better mismatch protection. Four parallel 1 ohm resistors gives you roughly the same resistance as the original.
gregjpeters said:
Only if your FETS are perfectly matched. Instead. connect 2 source resistors to each device's source pin, with no connection between the source pins. This will reduce the effects of transistor mismatching, but they still ought to be closely matched in pairs (IRFP240 to IRFP240, etc.)
You could use higher value source resistors for even better mismatch protection. Four parallel 1 ohm resistors gives you roughly the same resistance as the original.
That wont work, You have to use separate source resistor for each transistor as Bob says. Paralleling output devices has nothing to do with output power, thats purely a product of rail voltage divided by load, You can connect any number of transistors in parallel, +/- 35V rails still produce the same output power but with lower output impedance and of course a lighter dissipation task on each transistor.
Say guys, I just finished *****ing about DIYZONE posting
exactly the same schematics without permission.
I officially give you this permission here and now, but I think
we need to consider how this is to be done in the future,
otherwise other sites can point to DIYAudio as an example
of why it's OK.
exactly the same schematics without permission.
I officially give you this permission here and now, but I think
we need to consider how this is to be done in the future,
otherwise other sites can point to DIYAudio as an example
of why it's OK.
An example?
For reference, in the following, I only linked to a picture of a pile of stuff in my garage, but this could be substituted for copyrighted info as well. But, at this time, I hereby release the image of my messy garage to the public domain. . .)
The typically accepted, most honest way of doing this is to post a link to the source site directly, correct?
Such as:
http://www.tshouston.net/shop/spares2.jpg
instead of using the IMG tag (unless it is an embedded picture of your own without copyright from your own site to save on DIYAudio's bandwidth), such as:
Is it typically proper to alias the link such as:
Pile of junk
or is this also in bad taste, even though it goes to the source site?
Questioning the proper etiquette.
Best Regards to all,
Sandy.
*edit: Resized the picture to reduce wasted bandwidth. Sorry.
For reference, in the following, I only linked to a picture of a pile of stuff in my garage, but this could be substituted for copyrighted info as well. But, at this time, I hereby release the image of my messy garage to the public domain. . .)
The typically accepted, most honest way of doing this is to post a link to the source site directly, correct?
Such as:
http://www.tshouston.net/shop/spares2.jpg
instead of using the IMG tag (unless it is an embedded picture of your own without copyright from your own site to save on DIYAudio's bandwidth), such as:
An externally hosted image should be here but it was not working when we last tested it.
.
Is it typically proper to alias the link such as:
Pile of junk
or is this also in bad taste, even though it goes to the source site?
Questioning the proper etiquette.
Best Regards to all,
Sandy.
*edit: Resized the picture to reduce wasted bandwidth. Sorry.
IMHO
The method which most appropriately denotes the source of your reference and drives traffic to the intended site accordingly is:
See Nelson Pass Complimentary Zen Amp
Many websites have very specific policies about linking to their material and PassDIY may need to adopt same.
The method which most appropriately denotes the source of your reference and drives traffic to the intended site accordingly is:
See Nelson Pass Complimentary Zen Amp
Many websites have very specific policies about linking to their material and PassDIY may need to adopt same.
Sorry guys
Sorry to all who took offence to my posting of the schematics, particularly you Nelson. I have requested permission to modify the posts so I can remove them from the thread.
Unfortunately, now the thread has gone off topic, and I'm guessing my questions won't be answered, but now I am reluctant to ask again and waste bandwidth. Guess I'll just go buy a book.
Cheers.
Greg.
Sorry to all who took offence to my posting of the schematics, particularly you Nelson. I have requested permission to modify the posts so I can remove them from the thread.
Unfortunately, now the thread has gone off topic, and I'm guessing my questions won't be answered, but now I am reluctant to ask again and waste bandwidth. Guess I'll just go buy a book.
Cheers.
Greg.
In Paralleling devices you could probably stay with the same value
for the power resistors .5 ohm or so. The thing to do would be to
check it out in a working circuit.
Check out the Zen Variations Part 3 article. There's some info on
paralleling devices (they're in a PSU, but should still be some good info)
for the power resistors .5 ohm or so. The thing to do would be to
check it out in a working circuit.
Check out the Zen Variations Part 3 article. There's some info on
paralleling devices (they're in a PSU, but should still be some good info)
That would be great!!
Ingvar,
That would be most useful! The thing I don't understand is how you can increase the rail voltage while using the same bias (I really want to use 2 amps, at least) without exceeding the dissipation rating of the FETS (within reason - I don't want to be dissipating 100 watts per device!). Three more quick questions:
1. Will lowering the output impedence by using parallel FETS significantly reduce distortion?
2. Would it be possible to make a complementary, balanced amplifier - say a complementary son of zen? Seems this would be a good idea if it were possible (shows how little I know about this stuff). A schematic would be great!
3. How do these amps really sound?
Your help is most appreciated. Please don't hesitate to tell me to shut up if I begin to bother you.
Cheers.
P.S. A little story:
Currently, my amp is a home theatre A$1000 pioneer amplifer, with digital theatre sound, 5.1 channels (apparently 120w each), incredibly versatile user interface and remote control. While it will be snuffed at by true audiophiles, most "ordinary" people would say it sounds good. Anyway, I've never been able to say why, but I've never liked the sound, too sterile and sharp and cold. I find I can't listen to it for extended periods.
I was walking through DS electronics the other day (an Australian electronics chain - kind of like radioshack) and I saw a little 80w + 80w amp for A$140. I thought it was another one of those crappy cheap mass produced amps made it a sweatshop for $10. This amp has ventilation slots on the top and I casually looked inside and saw a very targe toroidal transformer and electrolytic capacitors (the amp weighs nearly 10 kg). I immediately changed my approach to the amp, and figured "if they have a power supply that decent, the rest can't be TOO bad" (Even my pioneer amp has a square tranny). The amp has no remote, no digital display, only balance, bass and treble controls (which can be switched out of the circuit by another button). Anyway, I figured "what the heck" and bought it.
Needless to say, for the cost, it sounds very nice, far better than the pioneer theatre amp. It sounds much warmer and lifelike, and according to the manual, has pretty much identical distortion characteristics to the pioneer amp, though hasn't got quite the same power. The bass is just delicious! Clearly, all you audiophiles would say it sounds like crap, and it probably does compared to an aleph or something. But it just shows how you can spend $140 on just an amplifier, or $1000 on a lower grade amplifier with lots of little digital add-ons and a remote, and get a nicer sound from the former. I really like this amp and am going to sell my old amp despite the greater power and adjustability.
Ingvar,
That would be most useful! The thing I don't understand is how you can increase the rail voltage while using the same bias (I really want to use 2 amps, at least) without exceeding the dissipation rating of the FETS (within reason - I don't want to be dissipating 100 watts per device!). Three more quick questions:
1. Will lowering the output impedence by using parallel FETS significantly reduce distortion?
2. Would it be possible to make a complementary, balanced amplifier - say a complementary son of zen? Seems this would be a good idea if it were possible (shows how little I know about this stuff). A schematic would be great!
3. How do these amps really sound?
Your help is most appreciated. Please don't hesitate to tell me to shut up if I begin to bother you.
Cheers.
P.S. A little story:
Currently, my amp is a home theatre A$1000 pioneer amplifer, with digital theatre sound, 5.1 channels (apparently 120w each), incredibly versatile user interface and remote control. While it will be snuffed at by true audiophiles, most "ordinary" people would say it sounds good. Anyway, I've never been able to say why, but I've never liked the sound, too sterile and sharp and cold. I find I can't listen to it for extended periods.
I was walking through DS electronics the other day (an Australian electronics chain - kind of like radioshack) and I saw a little 80w + 80w amp for A$140. I thought it was another one of those crappy cheap mass produced amps made it a sweatshop for $10. This amp has ventilation slots on the top and I casually looked inside and saw a very targe toroidal transformer and electrolytic capacitors (the amp weighs nearly 10 kg). I immediately changed my approach to the amp, and figured "if they have a power supply that decent, the rest can't be TOO bad" (Even my pioneer amp has a square tranny). The amp has no remote, no digital display, only balance, bass and treble controls (which can be switched out of the circuit by another button). Anyway, I figured "what the heck" and bought it.
Needless to say, for the cost, it sounds very nice, far better than the pioneer theatre amp. It sounds much warmer and lifelike, and according to the manual, has pretty much identical distortion characteristics to the pioneer amp, though hasn't got quite the same power. The bass is just delicious! Clearly, all you audiophiles would say it sounds like crap, and it probably does compared to an aleph or something. But it just shows how you can spend $140 on just an amplifier, or $1000 on a lower grade amplifier with lots of little digital add-ons and a remote, and get a nicer sound from the former. I really like this amp and am going to sell my old amp despite the greater power and adjustability.
Hi again Greg, just got home from the workshop.
Excuse me if i ramble a bit now and tell what You already know, but i think it´s a good idea to sort things out to know what You want and what to build.
Output power is a product of voltage drop through load, so the Zen v5, for instance, ( we keep this basic, no concern for forward voltage drop in output devices etc ) at +/- 30v rails has a voltage swing of 60v across the load, say load is 8 ohms, then output power is 60x60 / 8x8 = 56,25W RMS, 6 ohm load would give 100W providing the amp can deliver the current.
A look at Your story tells that You regard a seemingly smaller but quality oriented amp as superior to a massmarket large 5.1 featureloaded well known amp. I´ve looked into and repaired lots of amps of home cinema type, (actually i think Pioneers are often well built ) 5 x120W would need a powertransformer of at least 800W so the power rating of that amp seems to be nothing but a lie. The output power difference between 80 and 120W is about 2dB.
If You feel that power from the Pioneer is adequate a Zen v5 will sound a lot more powerful and will certainly be able to supply the current under heavy load.
Your questions: 1: paralleling will teoreticaly reduce distorsions as unlinearitys tend to be irregular, we should ask mr Pass, current capability will be improved and with 6 ohm load You would get a better bottom end.
2: If You want to go the differential (balanced) way i think it should stay as it is, but again, mr Pass teritory.
3: My only experience of Pass diy designs are the original Zen and Zen v5 ( and the MF Citation which i´ll never stop blabbing about) So my view is they sound detailed, fast almost like single end tube amps, produce a good soundstage, extremely dynamic and very powerfull but whit some speakers a bit "soft" in the bottom end. The cat also loves to sleep on top of those nice warm cabinets.
Excuse me if i ramble a bit now and tell what You already know, but i think it´s a good idea to sort things out to know what You want and what to build.
Output power is a product of voltage drop through load, so the Zen v5, for instance, ( we keep this basic, no concern for forward voltage drop in output devices etc ) at +/- 30v rails has a voltage swing of 60v across the load, say load is 8 ohms, then output power is 60x60 / 8x8 = 56,25W RMS, 6 ohm load would give 100W providing the amp can deliver the current.
A look at Your story tells that You regard a seemingly smaller but quality oriented amp as superior to a massmarket large 5.1 featureloaded well known amp. I´ve looked into and repaired lots of amps of home cinema type, (actually i think Pioneers are often well built ) 5 x120W would need a powertransformer of at least 800W so the power rating of that amp seems to be nothing but a lie. The output power difference between 80 and 120W is about 2dB.
If You feel that power from the Pioneer is adequate a Zen v5 will sound a lot more powerful and will certainly be able to supply the current under heavy load.
Your questions: 1: paralleling will teoreticaly reduce distorsions as unlinearitys tend to be irregular, we should ask mr Pass, current capability will be improved and with 6 ohm load You would get a better bottom end.
2: If You want to go the differential (balanced) way i think it should stay as it is, but again, mr Pass teritory.
3: My only experience of Pass diy designs are the original Zen and Zen v5 ( and the MF Citation which i´ll never stop blabbing about) So my view is they sound detailed, fast almost like single end tube amps, produce a good soundstage, extremely dynamic and very powerfull but whit some speakers a bit "soft" in the bottom end. The cat also loves to sleep on top of those nice warm cabinets.
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