howto: replacing the ALWSR pre-regulator by a VBE
- Thread starter teddy_pardo
- Start date
martin clark
pinko bodger
...that is, the 317 is arranged so that it keeps a constant 2.5v drop across the super-reg from SR input to SR output; a kind of cascode.
The VBE just feeds the SR with a very quiet raw supply; not quite the same thing, but very effective...
The VBE just feeds the SR with a very quiet raw supply; not quite the same thing, but very effective...
Hi,
I am installing home made Darlingtons (BC547C + D44H11 and PNP counterparts) instead of BDX33C in my SR's, because they sound way better, as you said.
I am even using this gyrator preceding LM317 or L1085 with great results.
But I ran out of D44H11 for a while. Since I need a low current PS, can I make a Darlington with two BC547C or will it be unstable???
Thanks
M
I am installing home made Darlingtons (BC547C + D44H11 and PNP counterparts) instead of BDX33C in my SR's, because they sound way better, as you said.
I am even using this gyrator preceding LM317 or L1085 with great results.
But I ran out of D44H11 for a while. Since I need a low current PS, can I make a Darlington with two BC547C or will it be unstable???
Thanks
M
teddy_pardo
Trade: Teddy Pardo
You can. Make sure you have a 150-250R resistor at the base of the first transistor.
Try to invert the order, linear regulator first gyrator after, better results.
Try to invert the order, linear regulator first gyrator after, better results.
Thanks Teddy,
Sorry, R from base to...?
The first schematic on this thread has indeed a 250R (R3) from gate to "filter node". I think that R is the one you are talking about.
I saw the schematics of BDX33C which has a 10K from base to emiter of first transistor (base of second) and a 150R from base to emiter of second transistor...
Cheers,
M
Sorry, R from base to...?
The first schematic on this thread has indeed a 250R (R3) from gate to "filter node". I think that R is the one you are talking about.
I saw the schematics of BDX33C which has a 10K from base to emiter of first transistor (base of second) and a 150R from base to emiter of second transistor...
Cheers,
M
teddy_pardo
Trade: Teddy Pardo
1. Yes that's the resistor.
2. I wouldn't recommend adding these resistors in this circuit, they increase the output impedance.
2. I wouldn't recommend adding these resistors in this circuit, they increase the output impedance.
Dear Teddy,
I report that the 2*BC547 Darlington works OK: more detailed and open sound, faster. Sounstage seems wider.
I change the filter to your recommended second order (previously, first order).
Does the 240R at the base of the first transistor needs to be installed also in BC547+D44HX circuits?
I read your "TeddyReg, How To" and PowerReg threads. I will surelly play with them.
Sorry if it's the wrong place or if it has been asked before but I can't source those tantalum caps, can I use electrolytic or film some where?
I will try the PowerReg on a chipamp for my Dad and maybe later on my UCD180 from my big active system (my Tannoy Autographs replica are >100dB efficient).
Many thanks for your "products"
and technical advices,
M
I report that the 2*BC547 Darlington works OK: more detailed and open sound, faster. Sounstage seems wider.
I change the filter to your recommended second order (previously, first order).
Does the 240R at the base of the first transistor needs to be installed also in BC547+D44HX circuits?
I read your "TeddyReg, How To" and PowerReg threads. I will surelly play with them.
Sorry if it's the wrong place or if it has been asked before but I can't source those tantalum caps, can I use electrolytic or film some where?
I will try the PowerReg on a chipamp for my Dad and maybe later on my UCD180 from my big active system (my Tannoy Autographs replica are >100dB efficient).
Many thanks for your "products"
and technical advices,M
teddy_pardo
Trade: Teddy Pardo
It's always good to have the base resistor, it's more critical when the hfe is very high
You can find Tantalum capacitors on eBay. Check with the seller if it's new or New Old Stock (NOS). Electrolytic and film work too, but I got better results with tantalums (and they are smaller too).
You can find Tantalum capacitors on eBay. Check with the seller if it's new or New Old Stock (NOS). Electrolytic and film work too, but I got better results with tantalums (and they are smaller too).
randytsuch
Active Member
Hi guys
I am planning to make a few of these for a project I am working on, but am not sure about something.
How would I make a darlington for a negative Jung?
Is it a PNP version of the bc547c (bc557c) and a D45H8?
I have looked at Teddy's pictures for it, and I can figure out everything else out if someone could give me a little help here. I also saw a remark about have to cross legs, I guess on the 557?
TIA
Randy
I am planning to make a few of these for a project I am working on, but am not sure about something.
How would I make a darlington for a negative Jung?
Is it a PNP version of the bc547c (bc557c) and a D45H8?
I have looked at Teddy's pictures for it, and I can figure out everything else out if someone could give me a little help here. I also saw a remark about have to cross legs, I guess on the 557?
TIA
Randy
Hi guys
I've been scanning through the "evolution" of teddy's improvement of the alswr superreg. I think I have got confused.
Just to clarify, does the this last version of the teddyreg intended to work in place of, or as well as, a superreg?
I am planning on powering a pre-amp with 2 or 4 outboard reg'd supplies. I will be getting an Avondale APX supply to output 30V. Is anything other than the 4 teddyregs needed to be to give 4 24V supplies?
Sorry for being stupid. I think I have got myself confused between different threads.
I've been scanning through the "evolution" of teddy's improvement of the alswr superreg. I think I have got confused.
Just to clarify, does the this last version of the teddyreg intended to work in place of, or as well as, a superreg?
I am planning on powering a pre-amp with 2 or 4 outboard reg'd supplies. I will be getting an Avondale APX supply to output 30V. Is anything other than the 4 teddyregs needed to be to give 4 24V supplies?
Sorry for being stupid. I think I have got myself confused between different threads.
mjrod99@comcast
pfm Member
Randy,the bc557c (negative version for D45H8)should be a direct drop in for the bc547c.I don't think you need any pin changes.I made mine for +/- with no problems.If you want a pleasant improvement,try the post by Ron in doing the Sziklai pair.Or better yet-do the TeddyReg!!It's fantastic.
Si-P: The TeddyReg is a direct replacement for the ALWSR and is better in every way.Takes a few seconds to stabilize though.Easier to build also.I made a few pcb's I've posted pictures of in the 'howto TeddyReg' post.I have put to rest all of my ALWSR's for now.As good as they are-the TeddyReg eats its lunch!!
Mike
Si-P: The TeddyReg is a direct replacement for the ALWSR and is better in every way.Takes a few seconds to stabilize though.Easier to build also.I made a few pcb's I've posted pictures of in the 'howto TeddyReg' post.I have put to rest all of my ALWSR's for now.As good as they are-the TeddyReg eats its lunch!!
Mike
Just curious, but which parameter is better? Temperature stability, regulation error, output impedance, bandwidth, noise, rejection of incoming noise?
teddy_pardo
Trade: Teddy Pardo
mjrod99@comcast
pfm Member
I'm presently using my TeddyRegs in my sacd player supplying a buffer circuit to output transformers.The sound is so much cleaner,less digital sound(hardly any before),more natural and easier on the ears.Bass is solid,deep expansive soundstage.No kiddin',better in every way than ALWSR or the VBE ALWSR.I'm planning to do my crossover using a star ground for +/- legs.I don't know if it will offer any advantages.I'll report back.
randytsuch
Active Member
Well you guys have talked me into it.
I am building a heavily modded squeezebox. I have a couple of output buffers I need to power with +/- 20VDC.
I was going to use a couple of VBE ALWSR's because I already have the boards and most of the parts, but have decided to build Teddy regs instead.
Since they are simplier, I am going to build 4 of them, one each for + and -20, for each buffer board. I am also going to build one for +5, to provide the analog +5VDC to the DAC in the SB. For the +3.3 VDC for the digital supply to the DAC, I plan to use a shunt reg.
Randy
I am building a heavily modded squeezebox. I have a couple of output buffers I need to power with +/- 20VDC.
I was going to use a couple of VBE ALWSR's because I already have the boards and most of the parts, but have decided to build Teddy regs instead.
Since they are simplier, I am going to build 4 of them, one each for + and -20, for each buffer board. I am also going to build one for +5, to provide the analog +5VDC to the DAC in the SB. For the +3.3 VDC for the digital supply to the DAC, I plan to use a shunt reg.
Randy
mjrod99@comcast
pfm Member
You will be mad at yourself for waiting so long to build them.I'm using 560R for my +/-5 ps.Comes out +4.97/-5.18vdc.Let us know what you think.
Mike
Mike
I have just put my order into RS, Cricklewood and ebay for enough parts to make lots of Teddyregs!
I was also going to order the parts to do the Avondale X12 Gainstage mods to my 92R, just to to keep me happy till I get some 821a boards.
I went to Avondale site to print off the "tips and tricks" page for the circuit diagram and the parts and.....
everything on the Avondale website has disappeared except for a rather stark front page!
Erk! Does anyone have a copy?
Oh, and does anyone know where to source a few 47uF Silmics?? Digikey do Elna RFS (these are Silmic II's aren't they?) but with a lead time of 2 months!
I was also going to order the parts to do the Avondale X12 Gainstage mods to my 92R, just to to keep me happy till I get some 821a boards.
I went to Avondale site to print off the "tips and tricks" page for the circuit diagram and the parts and.....
everything on the Avondale website has disappeared except for a rather stark front page!
Erk! Does anyone have a copy?
Oh, and does anyone know where to source a few 47uF Silmics?? Digikey do Elna RFS (these are Silmic II's aren't they?) but with a lead time of 2 months!