PSU DESIGN.
Hi,
3-5 Volts sounds like little regulation to me, look at the preamp PSU I presented in another thread it never varies , not even a mV.
What you seem to overlook is that the mere fact of using a tube reg is going to reject any effect the preceding PSU has by its' inherent feedback so PSRR is quite high, you won;t hear the type of rectification preceding it thanks to good PSU decoupling AND you'll still have a slow start for the tubes.
Cathode stripping is well documented, Gabe.
Tubes should be given at least ten seconds to warm up otherwise the anode is going to rip electrons from the cold cathode and that's not what you want for long life use.
You mean everything sound more or less the same on those?
Anyway, you probably didn't notice but I agreed with you from the start and reading you further seems to confirm my initial feeling that we both try to achieve the same thing although are paths seem a bit different and please, do call me Frank.
Cheers,
Hi,
3-5 Volts sounds like little regulation to me, look at the preamp PSU I presented in another thread it never varies , not even a mV.
What you seem to overlook is that the mere fact of using a tube reg is going to reject any effect the preceding PSU has by its' inherent feedback so PSRR is quite high, you won;t hear the type of rectification preceding it thanks to good PSU decoupling AND you'll still have a slow start for the tubes.
Cathode stripping is well documented, Gabe.
Tubes should be given at least ten seconds to warm up otherwise the anode is going to rip electrons from the cold cathode and that's not what you want for long life use.
You mean everything sound more or less the same on those?
Anyway, you probably didn't notice but I agreed with you from the start and reading you further seems to confirm my initial feeling that we both try to achieve the same thing although are paths seem a bit different and please, do call me Frank.
Cheers,
Gabevee said:
Gabe, after reading your post, and going back through your webpage on power supplies, I can partly see your point. So right now I am looking at the values I have in my power supply for the capacitors in the filter section. The first step is where I don't have information... I have to figure out the idle power draw... any guess on this 300b circuit that I have been working in mono? Also, if you were to take the power supply and change it to SS rectfication, what values for the initial resistors (in your schematic before the diodes) would you use, and what for the bypass caps on the diodes? Also, would you still keep the 47ohm resistor after the diodes? Last, what diodes do you suggest?
Thanks.
Hybrid Rectumfriers.
Hi,
Purrrrcisely.
If you dig a little in the previous threads you'll find diagrams for these plus a very well written explanation by Gary Pimm on how this works.
Basically you get little or no diode noise and a slow ramp up for the B+, all that with a pair of diodes and a tube rectifier.
Cheers,
Hi,
Purrrrcisely.
If you dig a little in the previous threads you'll find diagrams for these plus a very well written explanation by Gary Pimm on how this works.
Basically you get little or no diode noise and a slow ramp up for the B+, all that with a pair of diodes and a tube rectifier.
Cheers,
OK, Frank. Thank you.
In much of my travels, which admittedly is not far, I had not except for these forums read about cathode stripping. I don't doubt that it is a real phenomenon, any more than notching is or any of the other fascinating phenomena that exists in this fantastic science. I even agree and for my own personal experience discuss the inherent capacitance and inductances of straight wires and their affect on sound! Many would call that snake oil as much as I may seem to be implying that for cathode stripping.
My contention however is how bad is it really. If my tubes lasted only six months before a very noticable breakdown, I would go to either a slow start circuit or tube regulation in a heartbeat. As it is, neither I nor my friends and customers (usually one and the same, since they become friends afterwards) have had a problem with their tubes using SS rectification. And we've been using our amps for years of daily three to six hours a day listening.
Now, I need to do more research, but the strippping of electrons doesn't seem to be the problem, but the stripping off of the phosphor... or whatever the material is that is used for thermionic conduction (I don't recall off hand)... is the problem. But then I would think that voltage potential had a play in how bad that occurs also. One would think that modern television sets would suffer the most, being that they are all 100% (except fo the picture tube) solid state, and have upwards of 30,000 volts on their anodes. No doubt the cathode is subject to enourmous stripping problems. Yet they last for many years.
Just my thinking at this point.
As for 3-5 volt regulation, I am quoting from either Steve Bench's site or Glass Audio, or AudioXchange, or one of those. There will be some change in voltage under load, according to the article. I do recall it was about that much even with the best regulator circuit, using the shunt regulator (0A1, or whatever it is) with a triode. My problem with the circuit is that one needed something like a 400 volt supply to get 320 volts regulated.
Mach_Y,
I use a resistor in the center tap now, instead of at each diode. I use from 250 to 390 ohms. It is easier and gets the job done (I guess I need to update that site). Also, I originally used off the shelf 1000 PIV 2 amp diodes from Radio Shack. I just recently ordered 1500 PIV 1 amp from NTE electronics. Nothing special. No Schottky or high speed diodes. So long as the filter is good.
Typical current draw from a 300b at idle can be about 80 mA (that is with about 64 volts with an 800 ohm cathode resistor).
As for caps, whether you go tube or SS, for tube, the one right at the tube is important. Use no more than the recommended maximum, anywhere from 20-47 µF. After the choke I use anything from 100 to 330µF. For solid state, nothing less than 80µF after the rectifiers. Some use high voltage caramics in parallel with the diodes in case of spikes, and to ease the reverse voltage transition. 0.1 µF should do it.
BTW, in the back of the RCA tube manual is an amp that had 80µF right at the output of a 5Y3 as well as after the resistor! The recommended max is 33µF. So much for specs!
Gabe
In much of my travels, which admittedly is not far, I had not except for these forums read about cathode stripping. I don't doubt that it is a real phenomenon, any more than notching is or any of the other fascinating phenomena that exists in this fantastic science. I even agree and for my own personal experience discuss the inherent capacitance and inductances of straight wires and their affect on sound! Many would call that snake oil as much as I may seem to be implying that for cathode stripping.
My contention however is how bad is it really. If my tubes lasted only six months before a very noticable breakdown, I would go to either a slow start circuit or tube regulation in a heartbeat. As it is, neither I nor my friends and customers (usually one and the same, since they become friends afterwards) have had a problem with their tubes using SS rectification. And we've been using our amps for years of daily three to six hours a day listening.
Now, I need to do more research, but the strippping of electrons doesn't seem to be the problem, but the stripping off of the phosphor... or whatever the material is that is used for thermionic conduction (I don't recall off hand)... is the problem. But then I would think that voltage potential had a play in how bad that occurs also. One would think that modern television sets would suffer the most, being that they are all 100% (except fo the picture tube) solid state, and have upwards of 30,000 volts on their anodes. No doubt the cathode is subject to enourmous stripping problems. Yet they last for many years.
Just my thinking at this point.
As for 3-5 volt regulation, I am quoting from either Steve Bench's site or Glass Audio, or AudioXchange, or one of those. There will be some change in voltage under load, according to the article. I do recall it was about that much even with the best regulator circuit, using the shunt regulator (0A1, or whatever it is) with a triode. My problem with the circuit is that one needed something like a 400 volt supply to get 320 volts regulated.
Mach_Y,
I use a resistor in the center tap now, instead of at each diode. I use from 250 to 390 ohms. It is easier and gets the job done (I guess I need to update that site). Also, I originally used off the shelf 1000 PIV 2 amp diodes from Radio Shack. I just recently ordered 1500 PIV 1 amp from NTE electronics. Nothing special. No Schottky or high speed diodes. So long as the filter is good.
Typical current draw from a 300b at idle can be about 80 mA (that is with about 64 volts with an 800 ohm cathode resistor).
As for caps, whether you go tube or SS, for tube, the one right at the tube is important. Use no more than the recommended maximum, anywhere from 20-47 µF. After the choke I use anything from 100 to 330µF. For solid state, nothing less than 80µF after the rectifiers. Some use high voltage caramics in parallel with the diodes in case of spikes, and to ease the reverse voltage transition. 0.1 µF should do it.
BTW, in the back of the RCA tube manual is an amp that had 80µF right at the output of a 5Y3 as well as after the resistor! The recommended max is 33µF. So much for specs!
Gabe
siu sin man tho said:hi mach_y,
resisters arrived. Pls see th photos. All were use in my kits.
The Biggest one was made by noble( Japan's Made) & some carbon resisters will use in the kits too.
All were excellent quality./
thanks
thomas
Thomas,
Looks good on the resistors
You got more email.Mark
This is my 300b project.
the simple & good sound.
pls see the layout.
any suggestion to improve is welcome.
thanks
thomas
www.diyaudiocraft.com
the simple & good sound.
pls see the layout.
any suggestion to improve is welcome.
thanks
thomas
www.diyaudiocraft.com
Attachments
hi Mach_y,
I canno got your mail. Which mail box U send to me.
There was still had a little space to improve.
The improve point is the brown wire which was beside the yellow wire.
I want the coming power trans put the primary winding into the lower side, now is the upper side. The can use shortly wire to connect the AC power, less chance to take the AC noise. I test already. The sound will get a little bit silent than the old tower trans only improve this point.
U like diy~of Course. Me too.
Pls see my Brand name of the kit.
I made three type for diyer to choose. All use 99.99 Pure silver to hand made. The middle one is use hammer to punch the words. Other tow was laser trimmed but one was flash surface, the another one is sandy surface.
NIl coating for the silver plate. But use 99.99 pure silver plate will oxidized with a little gold colour, not black. is it very well.
I will not put the plate into the chassis. the diyer can decide the location of the plate by thenselves.
DO`IT`YOURSELF~OF COURSE>>>>>>>>>>>>>>Yeh!!!!!
Every plate weight 12.82~13.86 gram weight 99.99 pure silver.
thanks
thomas
I canno got your mail. Which mail box U send to me.
There was still had a little space to improve.
The improve point is the brown wire which was beside the yellow wire.
I want the coming power trans put the primary winding into the lower side, now is the upper side. The can use shortly wire to connect the AC power, less chance to take the AC noise. I test already. The sound will get a little bit silent than the old tower trans only improve this point.
U like diy~of Course. Me too.
Pls see my Brand name of the kit.
I made three type for diyer to choose. All use 99.99 Pure silver to hand made. The middle one is use hammer to punch the words. Other tow was laser trimmed but one was flash surface, the another one is sandy surface.
NIl coating for the silver plate. But use 99.99 pure silver plate will oxidized with a little gold colour, not black. is it very well.
I will not put the plate into the chassis. the diyer can decide the location of the plate by thenselves.
DO`IT`YOURSELF~OF COURSE>>>>>>>>>>>>>>Yeh!!!!!
Every plate weight 12.82~13.86 gram weight 99.99 pure silver.
thanks
thomas
Attachments
Which amp?
I just found this thread, which I’ve read through pretty quickly)
I’m primarily interested in the DRD circuit, but a couple of designs are being discussed . . .
Forgive the dumb questions:
Alex
On 4-18 you wrote:
“This amp I built for myself was made from parts I already have from my previous project.”
- is the *DRD * circuit, or the ‘JE Labs 300B’?
Mark on 4-19 you wrote:
The parts list spreadsheet you zipped – is that also the *DRD * circuit??
If they’re both for the JE Labs 300B, Alex have done a list for the DRD?
Thanks
Richard
I just found this thread, which I’ve read through pretty quickly)
I’m primarily interested in the DRD circuit, but a couple of designs are being discussed . . .
Forgive the dumb questions:
Alex
On 4-18 you wrote:
“This amp I built for myself was made from parts I already have from my previous project.”
- is the *DRD * circuit, or the ‘JE Labs 300B’?
Mark on 4-19 you wrote:
The parts list spreadsheet you zipped – is that also the *DRD * circuit??
If they’re both for the JE Labs 300B, Alex have done a list for the DRD?
Thanks
Richard
By the way, I have never built a JE Labs 300B although, I would like to try it. The circuit I did try was also from Electra-Print, this circuit uses 6SL7 as the voltage stage, cascaded directly into a 6BL7 wired as a cathode follower.
This circuit, is the sweetest circuit I have listened too, it sounded like a 2A3 amp except with much more power. I think this circuit is better than the JE Labs 300B, although I have yet to build one.
I actually like this amp better than the DRD. The DRD has its character, very detailed, a lot of slam. If this is what you are
looking for, then the DRD is for you, but if you are looking for
sweet sound, airy smooth sound, then the DRD may not be
for you.
Right now, I am playing around with a driver that uses the MU Stage topology. This circuit seems promising. The sound is in between my two amps, more detail than my 300B amp that uses 6SL7 as driver but less detail than the DRD. I like the sound of the amp so far(I think).
Alex
This circuit, is the sweetest circuit I have listened too, it sounded like a 2A3 amp except with much more power. I think this circuit is better than the JE Labs 300B, although I have yet to build one.
I actually like this amp better than the DRD. The DRD has its character, very detailed, a lot of slam. If this is what you are
looking for, then the DRD is for you, but if you are looking for
sweet sound, airy smooth sound, then the DRD may not be
for you.
Right now, I am playing around with a driver that uses the MU Stage topology. This circuit seems promising. The sound is in between my two amps, more detail than my 300B amp that uses 6SL7 as driver but less detail than the DRD. I like the sound of the amp so far(I think).
Alex
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.