Take out one 10 V Zener. Essentially the output voltage is the Zener stack total voltage (adding them up) minus 4 V which is the Vgs drop. So for this supply in the picture it is 10+10+9.1 = 29 minus 4 which is 25 V. For 15 V you need 10+9.1 = 19.1 minus 4 which is 15 V.
/UrSv
/UrSv
It's that simple?
I was hoping someone would say that the voltage was related to the zeners and that changing the zener value changes the output voltage. THANK YOU! Where does my voltage of 22.7 volts figure into the equation?
John
I was hoping someone would say that the voltage was related to the zeners and that changing the zener value changes the output voltage. THANK YOU! Where does my voltage of 22.7 volts figure into the equation?
John
THANK YOU! Where does my voltage of 22.7 volts figure into the equation?
I would imagine in place of 32V.
I would imagine in place of 32V.
?
Well, that is what you are doing. You are changing the Zener voltage (or the sum of them) which determines the output voltage.
My first sentence probably should have read:
Take out one 10 V Zener per rail.
As for the 22.7 V it should be high enough so that there is some margin between that voltage minus the ripple and your output voltage. For the Zen V4 it is 50 V in and 40 V out (I think) which gives a 10 V difference which is in the same ballpark as you are here. You should be fine. Check the output of the regulator and if it seems to be bad add some caps before the reg which would decrease the ripple and improve your margin.
Other than that the equation gives you that the input voltage minus the output voltage times the current is the dissipation in the regulator. In this case with 22.7 V in and 15V out you would have 31 W heat to get rid of if the current is 4 A. For each rail.
/UrSv
Well, that is what you are doing. You are changing the Zener voltage (or the sum of them) which determines the output voltage.
My first sentence probably should have read:
Take out one 10 V Zener per rail.
As for the 22.7 V it should be high enough so that there is some margin between that voltage minus the ripple and your output voltage. For the Zen V4 it is 50 V in and 40 V out (I think) which gives a 10 V difference which is in the same ballpark as you are here. You should be fine. Check the output of the regulator and if it seems to be bad add some caps before the reg which would decrease the ripple and improve your margin.
Other than that the equation gives you that the input voltage minus the output voltage times the current is the dissipation in the regulator. In this case with 22.7 V in and 15V out you would have 31 W heat to get rid of if the current is 4 A. For each rail.
/UrSv
Sorry, maybe I misunderstood. Exactly as Peter said:
Your input voltage of 22.7 V goes where the 32 V goes in the posted example and you take your 15 V where the 25 V is.
/UrSv
Your input voltage of 22.7 V goes where the 32 V goes in the posted example and you take your 15 V where the 25 V is.
/UrSv
Do you really think it is worth regulating the supply on an Aleph-X? As mentioned before in this thread, the X should have excellent supply rejection, and your regulator is going to dissipate a tremendous amount of power. Something near 100 watts I would guess, over only two transistors.
No need for the PSU to have 2 transistors. Just add a few more. Check the Zen series documents.
/UrSv
/UrSv
"If I have an LC output of 22.7 volts and wanted to regulate it down to 15 volts what changes would I make to the following diagram?"
two or more big caps and a heatsunk dale 250w wirewound in the middle (one for each rail)
two or more big caps and a heatsunk dale 250w wirewound in the middle (one for each rail)
250W Dales and extra heat sink space might be more expensive than proper low voltage transformer. I'm not sure if Aleph X will sound better with active regulation anyway.
While I get excellent noise specs with AlephX circuits with
unregulated supplies, many of the probable applications
are with high efficiency speakers, and some form of ripple
reduction technique is recommended in order to get the
best possible performance. The XA200 is using RC type
filtering, but LC or active are all perfectly acceptable.
unregulated supplies, many of the probable applications
are with high efficiency speakers, and some form of ripple
reduction technique is recommended in order to get the
best possible performance. The XA200 is using RC type
filtering, but LC or active are all perfectly acceptable.
Aleph-X... Soon could I hear the talks about comparison and pride of the sound...?!!? Just curious...
JH
JH
I have one channel running on the bench. Sounds ... just like every other thing I've used to drive that decrepit test speaker.
home from work, lots of posts; life is good.
I happen to have two 1000 v/a transformers from my now defunct Aleph 2 project. I fell in love with the AX and haven't looked back since. Now, what to do with those two massive trannies? This is what prompted the question regarding the regulated circuit offered by Nelson in the Z4 article.
By running an LC filter and tying the tranny's primaries in series and loading down the resulting output with 1000 watt light bulbs, I ended up with the 22.7 volts. Perhaps it would be easier to adjust the resistor values in the AX and operate it on 22.7 volts. I'm a carpenter, not an engineer, so even with the aid of the Aleph 3? schematics, I'm not positive if I'll get all of the values correct. Anybody want to teach me a few tricks?
John
I happen to have two 1000 v/a transformers from my now defunct Aleph 2 project. I fell in love with the AX and haven't looked back since. Now, what to do with those two massive trannies? This is what prompted the question regarding the regulated circuit offered by Nelson in the Z4 article.
By running an LC filter and tying the tranny's primaries in series and loading down the resulting output with 1000 watt light bulbs, I ended up with the 22.7 volts. Perhaps it would be easier to adjust the resistor values in the AX and operate it on 22.7 volts. I'm a carpenter, not an engineer, so even with the aid of the Aleph 3? schematics, I'm not positive if I'll get all of the values correct. Anybody want to teach me a few tricks?
John
Re: home from work, lots of posts; life is good.
I am actually using one of my Aleph 2 transformer for my Aleph-X. I purchased it from Victoria Magnetics, and he has removed the secondaries, and is winding new secondaries onto it. It already had split primaries, so I am having him wind 4 sets of 25v 10A secondaries onto it, giving 4x25vac or 4x12.5vac, depending on the arrangement of the primaries. With this, I should get around 17v, or 34v for an Aleph 5 if I decide to get a bigger transformer for the AX later. I will use it for a stereo AX for now.
--
Brian
carpenter said:
I am actually using one of my Aleph 2 transformer for my Aleph-X. I purchased it from Victoria Magnetics, and he has removed the secondaries, and is winding new secondaries onto it. It already had split primaries, so I am having him wind 4 sets of 25v 10A secondaries onto it, giving 4x25vac or 4x12.5vac, depending on the arrangement of the primaries. With this, I should get around 17v, or 34v for an Aleph 5 if I decide to get a bigger transformer for the AX later. I will use it for a stereo AX for now.
--
Brian
Fancy that......
Nice trick, Brian. Unfortunately, my transformers are manufactured by Plitron. I might as well wait for the discovery of Atlantis, cause that's probably how long it would take to get my transformers re-manufactured. So, I need another trick. Anybody got one up their sleeve?
John
Nice trick, Brian. Unfortunately, my transformers are manufactured by Plitron. I might as well wait for the discovery of Atlantis, cause that's probably how long it would take to get my transformers re-manufactured. So, I need another trick. Anybody got one up their sleeve?
John
Re: home from work, lots of posts; life is good.
John,
That's exactly what I did. I converted my A75 amp intp Aleph X with primaries run in series and I'm getting +/- 20V after filtering. If you have enough heatsinks, there is no problem running Greys amp at higher powers. He explained in the beginning of the thread how to calculate the values.
If you run the amp at 22.7 V you would probably end up with 100W per channel, you'd need at least 3 pairs of devices per side (with total of 12 per channel) and your source resistors would be around 0.5-0.6ohm. Maybe two ore three other resistors values would have to be changed. I calculated my values roughly and will see how they worked out when the amp will be operating.😉
You got one other choice. Why not built the smaller version first and purchase appropriate transformers and then, when somebody will finalise bigger version of Aleph X, built another amp utilising your big trafos and go bi-amping.
But as usually, it all depends on available heatsinks.😉
carpenter said:
John,
That's exactly what I did. I converted my A75 amp intp Aleph X with primaries run in series and I'm getting +/- 20V after filtering. If you have enough heatsinks, there is no problem running Greys amp at higher powers. He explained in the beginning of the thread how to calculate the values.
If you run the amp at 22.7 V you would probably end up with 100W per channel, you'd need at least 3 pairs of devices per side (with total of 12 per channel) and your source resistors would be around 0.5-0.6ohm. Maybe two ore three other resistors values would have to be changed. I calculated my values roughly and will see how they worked out when the amp will be operating.😉
You got one other choice. Why not built the smaller version first and purchase appropriate transformers and then, when somebody will finalise bigger version of Aleph X, built another amp utilising your big trafos and go bi-amping.
But as usually, it all depends on available heatsinks.😉