Chris I sent you an email with the content of these power supplys. they are SMPS they offer sevral configs which apear to meet the needs I have. Could it reall y be as simple as wiring these up ? I am aware I would have to run 3 seperate power supplys which to me is no big deal.
as for the hackticular reapirs yeah thats pretty much it.
http://www.connexelectronic.com/
These guys have a 50 and 80v and a preamp power supply setup for 50v. I can step that circut down easily enough.
Does these look like quality parts ? The specs are right at the outer limits of the transistors.
as for the hackticular reapirs yeah thats pretty much it.
http://www.connexelectronic.com/
These guys have a 50 and 80v and a preamp power supply setup for 50v. I can step that circut down easily enough.
Does these look like quality parts ? The specs are right at the outer limits of the transistors.
Hi Kramerguy,
I'll have a look.
I think your primary power supply should be a big 'ole transformer, EI core type. These are simple and reliable.
From your DC secondaries of +/- 80 VDC, you can step these down to supply your +/- 50 V supply and still further down to your +/- supplies for the op amps in your preamp section.
-Chris
I'll have a look.
I think your primary power supply should be a big 'ole transformer, EI core type. These are simple and reliable.
From your DC secondaries of +/- 80 VDC, you can step these down to supply your +/- 50 V supply and still further down to your +/- supplies for the op amps in your preamp section.
-Chris
Thank you very much. these have a very heavily filtered output as far as can see and I should assume " could be a stupid assumption however" that this should perform at least as good as the original transformer if not slightly better thanx to the enhanced specs. it is roughly 2x the power supply replacing the transformer with 3 new power supplys and thats at RMS ratings.
That is if I am not underestimating the capability of the OE power supply.
That is if I am not underestimating the capability of the OE power supply.
anatech said:
Hi Kramerguy,
These look as though they need a power transformer as well. That would be the same thing you need anyway.
My original thought was for you to supply your high voltage transformer with higher current ratings to cover the other supply requirements. Then use a switching power supply to drop the voltages to your other required supplies. The side benefit would be that your lower voltage supplies are now regulated.
-Chris
These look as though they need a power transformer as well. That would be the same thing you need anyway.
My original thought was for you to supply your high voltage transformer with higher current ratings to cover the other supply requirements. Then use a switching power supply to drop the voltages to your other required supplies. The side benefit would be that your lower voltage supplies are now regulated.
-Chris
I have been comming up empty on that one. most I seem to find is 56volt and I really would like to not loose the 4 and 2 ohm performance of the amplifier.
I may goto a switching power supply. I am getting detials from connex Electronics about what I would need to use with the peices they offer. The only thing I like about it is the weight reduction. If I get it to work I will post up schematics and parts info for the diy guys. Those SMPS supplies look pretty reasonable for cost.
I may goto a switching power supply. I am getting detials from connex Electronics about what I would need to use with the peices they offer. The only thing I like about it is the weight reduction. If I get it to work I will post up schematics and parts info for the diy guys. Those SMPS supplies look pretty reasonable for cost.
anatech said:
I would stack one of each of these, and wire for 57-31.6-0-31.6-57 at 600VA. A few turns could be added for the low power ±12V supply.
http://www.antekinc.com/AN-3230.pdf
http://www.antekinc.com/AN-3225.pdf
You might go to a 400VA on the lower tier if you have the space.
http://www.antekinc.com/AN-3230.pdf
http://www.antekinc.com/AN-3225.pdf
You might go to a 400VA on the lower tier if you have the space.
This one is a bit more then stock but I think this may work better.
Thanx for the link by the way.
http://www.antekinc.com/PS-15D80R.pdf
PS-15D80R12
the Transistors the 15003 have high thermal disaption ratings the then 15024 so they should be ok with higher voltage. Worst that happens is that I get a good output boost at high impedences.
Or I could integrate this monster right into my existing power supply ??
http://www.antekinc.com/AN-15475.pdf
How much do you think it would effect the transistor bias ? Would I need to rebais the gain side of the circut for more drive current to sink the extra voltage or do you think it would be ok ?
My thinking may be upside down here It is early and I have family driving me crazy so I could wrong about this.
Thanx for the link by the way.
http://www.antekinc.com/PS-15D80R.pdf
PS-15D80R12
the Transistors the 15003 have high thermal disaption ratings the then 15024 so they should be ok with higher voltage. Worst that happens is that I get a good output boost at high impedences.
Or I could integrate this monster right into my existing power supply ??
http://www.antekinc.com/AN-15475.pdf
How much do you think it would effect the transistor bias ? Would I need to rebais the gain side of the circut for more drive current to sink the extra voltage or do you think it would be ok ?
My thinking may be upside down here It is early and I have family driving me crazy so I could wrong about this.
Hi Kramerguy,
You are basically buying a power transformer. So, why not simply buy the correct one? You should be able to find unmounted power transformers where you are looking, but I would recommend an EI over a toroid transformer.
A lower supply voltage will affect your 8 ohm performance more than your low impedance performance. This is because most amplifiers do not actually double their output as the load resistance is halved. Your current limiting circuit has the final word down at 2 ohms.
If you are all hot and bothered to start swapping output transistors, why not go with MJ21196? The SOA is roughly the same as the MJ15003, but you gain the high voltage ratings of 250 VDC with these. Mind you, the MJ15024 are excellent power transistors. I wouldn't bother changing them unless some are blown. Then I would buy the least expensive of the two types.
-Chris
You are basically buying a power transformer. So, why not simply buy the correct one? You should be able to find unmounted power transformers where you are looking, but I would recommend an EI over a toroid transformer.
I don't see this. Toroid transformers are wide band devices and will pass more line garbage into your equipment. The emitted flux from a good EI transformer is not that hard to deal with either. I suspect you have an EI type in there originally. Is it an open frame or are there end bells?
56 V * 1.414 = 79.184 VDC (Call it 79 VDC, close enough?). Does that look like a familiar voltage? That is 80 VDC for all intents and purposes.
A lower supply voltage will affect your 8 ohm performance more than your low impedance performance. This is because most amplifiers do not actually double their output as the load resistance is halved. Your current limiting circuit has the final word down at 2 ohms.
Say what??! The maximum C-E voltage for an MJ15003 is 140 VDC, your MJ15024 are rated at 250 VDC. With your original supply voltages of +/- 80 VDC, your outputs will see 160 VDC when there is no load and you clip the output waveforms. That's negative headroom.
If you are all hot and bothered to start swapping output transistors, why not go with MJ21196? The SOA is roughly the same as the MJ15003, but you gain the high voltage ratings of 250 VDC with these. Mind you, the MJ15024 are excellent power transistors. I wouldn't bother changing them unless some are blown. Then I would buy the least expensive of the two types.
-Chris
I agree on the EI vs torodial.
the mj15003 transistors are running at higher frequencys then the 15024 in the amplifier. It is a Biamp arrangement.
As to what is better as I was told the 15003 is a higher powered transistor then the 15024 but that could be total hog wash. I haven't looked at the specs on the 15024 vs 15003.
I may upgrade to newer improved version transistors
I will investigate the other option of using a different transformer. If I limit volatges do I not also limit total wattage available. I understand that riasing the voltage will have more effect on 8 10 16 ohm performance vs lower impedences but that being siad if the voltage is not there we can't move the amperage even it we drop the impdence.
I am curious how we get 1.41 x 59 volts though ? I must have missed something here.
the mj15003 transistors are running at higher frequencys then the 15024 in the amplifier. It is a Biamp arrangement.
As to what is better as I was told the 15003 is a higher powered transistor then the 15024 but that could be total hog wash. I haven't looked at the specs on the 15024 vs 15003.
I may upgrade to newer improved version transistors
I will investigate the other option of using a different transformer. If I limit volatges do I not also limit total wattage available. I understand that riasing the voltage will have more effect on 8 10 16 ohm performance vs lower impedences but that being siad if the voltage is not there we can't move the amperage even it we drop the impdence.
I am curious how we get 1.41 x 59 volts though ? I must have missed something here.
Hi Kramerguy,
The act of rectifying and filtering the AC is in fact a peak hold circuit of sorts. You are finding the peak voltage and storing that on your filter capacitors. The peak to RMS reading has a conversion that is 1.414 (or 0.7071 depending on which way you are going). That means that your RMS rating of 56 VAC will become 80 VDC [56 * 1.414 = 79.2]. You would also subtract your diode drops from the AC value, plus a fudge factor depending on your current draw that also decreases the DC voltage through ripple voltage. I am calling the voltage 80 VDC instead of the actual 79.18.... VDC it really is, less diode drops and other factors. Close enough for our purposes.
I used to see this from people trying to increase the output power of an amplifier (which is a function of available voltage).
-Chris
It was 56 V.
The act of rectifying and filtering the AC is in fact a peak hold circuit of sorts. You are finding the peak voltage and storing that on your filter capacitors. The peak to RMS reading has a conversion that is 1.414 (or 0.7071 depending on which way you are going). That means that your RMS rating of 56 VAC will become 80 VDC [56 * 1.414 = 79.2]. You would also subtract your diode drops from the AC value, plus a fudge factor depending on your current draw that also decreases the DC voltage through ripple voltage. I am calling the voltage 80 VDC instead of the actual 79.18.... VDC it really is, less diode drops and other factors. Close enough for our purposes.
These will not be a meaningful difference to be honest with you. Both are excellent transistors and the reason given will not make a meaningful difference. I think the case temperature would probably limit safe output rather than the current ratings on these parts. Once you consider that suggestion in the light of your reality, it doesn't make any sense at all. Someone read a spec sheet without understanding what it actually meant for your amplifier.
I used to see this from people trying to increase the output power of an amplifier (which is a function of available voltage).Why? It isn't an upgrade unless the parts are defective. The parts used in your amp are very well regarded to begin with. There are a ton of factors to consider in any attempt to improve the performance of an amplifier. Simply "upgrading" the outputs will not get you there unless you are solving a problem with the old ones.
Are you saying the amplifier already had two different kinds of outputs? The MJ15024 types are great for either location. The MJ15003 could only be used for the lower power amplifier due to the voltage breakdown ratings.
-Chris
Hi Chris,
It contains two different amplifiers (one for highs and one for lows). The high amp uses 2 pairs of MJ15003 plus 1 pair as drivers on +-45V while the low amp uses 3 pairs of MJ15024 plus 1 pair as drivers on +-80V for lows.
So there isn't anything strange going on.
But the earlier suggestion of regulating down the +-80V rails to +-45V isn't very practical really as it is powering the HF poweramp. I'd definetely use two transformers.
It contains two different amplifiers (one for highs and one for lows). The high amp uses 2 pairs of MJ15003 plus 1 pair as drivers on +-45V while the low amp uses 3 pairs of MJ15024 plus 1 pair as drivers on +-80V for lows.
So there isn't anything strange going on.
But the earlier suggestion of regulating down the +-80V rails to +-45V isn't very practical really as it is powering the HF poweramp. I'd definetely use two transformers.
Hi megajocke,
Now, another transformer would make everything much more simple. I suggested this early on I think. Either that or someone else did, but this would be my first approach.
-Chris
Yep, that I understood. Just clarifying the transistor types in each.
See, now that makes no sense at all to me. They could have stuck with MJ15024 types all around and eliminated a skew or two.
Actually, there should be no problem doing this. Just think of a Carver Lightstar with the rails stuck at +/- 45 VDC. A down converter would work just fine. That is essentially what your converter would be doing. Add to that the HF amp supply voltages would then be regulated tightly. That should sound better as the Vas would run from stabilized voltages.
Now, another transformer would make everything much more simple. I suggested this early on I think. Either that or someone else did, but this would be my first approach.
-Chris
Ah, OK.
I agree about the regulators, with a switching supply it's perfectly possible to regulate it down of course! But design of such a thing is nontrivial and without experience it isn't really a realistic option. A linear power supply could be used but will dissipate more power than the driven amp itself and will require about double the power supply power for the HF amp.
Of course they could have stayed with MJ15024:s all around but once upon a time (when the amp was made) MJ15003:s were probably cheaper for the manufacturer than MJ15024:s. Today, MJ21196 seems to be less expensive than both those types though.
I agree about the regulators, with a switching supply it's perfectly possible to regulate it down of course! But design of such a thing is nontrivial and without experience it isn't really a realistic option. A linear power supply could be used but will dissipate more power than the driven amp itself and will require about double the power supply power for the HF amp.
Of course they could have stayed with MJ15024:s all around but once upon a time (when the amp was made) MJ15003:s were probably cheaper for the manufacturer than MJ15024:s.
Today, MJ21196 seems to be less expensive than both those types though.- Status
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