ble0t said:gengis,
Unfortunately, no
I was having a couple other boards made (very small proto run), so I quick whipped up this one since I had some panel space left and added it to the order. I could post the .brd file if you like...it'd be quite easy to etch I suppose.
Would you be willing to share the design for those of us who could make our own boards?
Thanks, Terry
jacco vermeulen said:
OK, I DL'd and installed Eagle Free. I can open the file but is there a way to print a black and white foil pattern with this program?
Thanks, Terry
PS. By the way I have those very caps that I bought from JEA when I built my ESP P101. Back then I think they sold for about $50 for twenty five of them.
Terry-
You need to export an image (BMP, JPG etc) from the File menu.
I usually then open it in PhotoShop to do any cleanup I want, such as upping the contrast so it's purely black and white, though I guess you could do the in Paint as well.
I also delete the traces underlying the pad holes before making it high contrast, so I can see where I am supposed to be drilling.
You need to export an image (BMP, JPG etc) from the File menu.
I usually then open it in PhotoShop to do any cleanup I want, such as upping the contrast so it's purely black and white, though I guess you could do the in Paint as well.
I also delete the traces underlying the pad holes before making it high contrast, so I can see where I am supposed to be drilling.
Hi Jondoe,
I asked a similar Q a few pages ago (although not as direct as yourself) to prompt a discussion but your's is the first to come up.
I intend doing a separate supply to the LTP/VAS/driver stage. My Q was do we regulate? and what volts above the main PSU?
Re your query about regulating and latching the output;- If you regulate the driver board it will run at constant voltage, but the main PSU voltage will vary with supplier's mains input voltage. Therefore your volts difference will change from hour to hour and day to day.
The majority of the driver board runs in ClassA except the drivers which fall out of ClassA at high output current. Your regulated supply must allow for this. Output current/Output hFE gives base current = driver current approx. Could exceed 1000mA!!! You could do a reg for all upto predriver and leave driver on the main PSU.
I intend adding 2 windings giving a few volts AC onto the main transformer core. When rectified these extra volts will sit on top of the main PSU volts to give a raised input to the lo current reg. (one each for plus & minus).
I asked a similar Q a few pages ago (although not as direct as yourself) to prompt a discussion but your's is the first to come up.
I intend doing a separate supply to the LTP/VAS/driver stage. My Q was do we regulate? and what volts above the main PSU?
Re your query about regulating and latching the output;- If you regulate the driver board it will run at constant voltage, but the main PSU voltage will vary with supplier's mains input voltage. Therefore your volts difference will change from hour to hour and day to day.
The majority of the driver board runs in ClassA except the drivers which fall out of ClassA at high output current. Your regulated supply must allow for this. Output current/Output hFE gives base current = driver current approx. Could exceed 1000mA!!! You could do a reg for all upto predriver and leave driver on the main PSU.
I intend adding 2 windings giving a few volts AC onto the main transformer core. When rectified these extra volts will sit on top of the main PSU volts to give a raised input to the lo current reg. (one each for plus & minus).
Thanks Brian,
I played around with Eagle a little bit and I found if I went into the view>display/hide layers... menu and only selected "bottom, pads, drills and milling" then it printed out a nice black foil pattern with all the holes well marked on my laser printer.
Very cool!
Thanks guys
Terry
PS. I had to go to the tool menu and click Ratsnest to get a solid ground plane in the center.
I played around with Eagle a little bit and I found if I went into the view>display/hide layers... menu and only selected "bottom, pads, drills and milling" then it printed out a nice black foil pattern with all the holes well marked on my laser printer.
Very cool!
Thanks guys
Terry
PS. I had to go to the tool menu and click Ratsnest to get a solid ground plane in the center.
still4given said:
Dude, you just wanted to show us you're a software genius !!
Once, i did a 48 hour registration of incoming voltagelevel, in my apartment at the time, fed it into my pc and plotted it on paper. (dont laugh, that was 1988 or so)
Turned out there is little variation during daytime overhere, peak voltage occurs at night.
Not surprising, at night average load is the lowest.
I suppose this may differ when you are close to high power consumers, any kind of industry.
I constructed a number of Elektor amplifiers with different voltages for front end and output, all by heightening PS voltage by means of a step-up transformer and voltage regulation after that.
Before those i did a German Mosfet design with fully separate PS's for both stages.
Both worked just fine.
To add to Andrew's post : like me you could opt for dual regulated stages with separate transformers, one for the LTP and VAS, one for the driver stage.
Only the VAS needs sufficient voltage, the stages in front just deliver current to make the voltage swing, and get enough current to fully drive the output.
The latter is not a problem, if you multiply all hFe values the result is huge, collector resistors are there to limit to what is just needed, the optimum of noise level and bandwidth for the devices preferred.
For a regulator to function properly you need some extra volts, that is the main reason for raising the voltage.
Of course, with the topology of the Leach my words are indeed a trifle dodgy.
Question was whether it is "needed" or has benefits to raise voltage level for all stages minus the output when employing voltage regulation.
Positive rails:
The base of predriver, driver and output devices will be 0.60 volt higher than voltage at their emitter.(all npn's)
To fully drive the output devices to peakvoltage the emitter of the pnp device T8 needs 1.80 volts more.
T1 serves as a voltage regulator, with a positive voltage at the entrance T2 will need more current from its collector.
As R2 can not deliver more the extra current is drawn from the base of T8, which it will get from its collector as it is a pnp device.
The base of T1 is kept at 40 volts because of the 2 Zener diodes, raising voltage is not needed.
As the emitter of T2 is connected to the minus rails through R9/R20/R22 current would increase, but given the high value of R20 not of great significance.
With Jens's layout its purely academic, current through R2/R21 is so low that voltage can be raised to a very high level without the need to change the value, same for R3/R22, R24/R35.
So, for those opting for voltage regulation, a separate higher voltage rails connected to the pads of R1/R23 is the easiest.
The 0.60V difference because of the driver collector on the regular PS voltage will not matter.
Up till the driver, if higher voltage on the front end is desired, it has to go on all lines.
Question was whether it is "needed" or has benefits to raise voltage level for all stages minus the output when employing voltage regulation.
Positive rails:
The base of predriver, driver and output devices will be 0.60 volt higher than voltage at their emitter.(all npn's)
To fully drive the output devices to peakvoltage the emitter of the pnp device T8 needs 1.80 volts more.
T1 serves as a voltage regulator, with a positive voltage at the entrance T2 will need more current from its collector.
As R2 can not deliver more the extra current is drawn from the base of T8, which it will get from its collector as it is a pnp device.
The base of T1 is kept at 40 volts because of the 2 Zener diodes, raising voltage is not needed.
As the emitter of T2 is connected to the minus rails through R9/R20/R22 current would increase, but given the high value of R20 not of great significance.
With Jens's layout its purely academic, current through R2/R21 is so low that voltage can be raised to a very high level without the need to change the value, same for R3/R22, R24/R35.
So, for those opting for voltage regulation, a separate higher voltage rails connected to the pads of R1/R23 is the easiest.
The 0.60V difference because of the driver collector on the regular PS voltage will not matter.
Up till the driver, if higher voltage on the front end is desired, it has to go on all lines.
I will be regulating the whole amp, front end and current stages. Each stage will have it's own feed but with one common regulator per channel. My regulator design is old but the way I look at it, it's still better than just a capacitor bank.
As for the necessity? Well that certainly is debatable. However, the GC chip amps also have high PSRR and users there are now realising the benefits of proper regulation.
This amp will join my stable of Leach amps, Low Tim 3, Original Double Barrel (with the wings) both also fully regulated.
As for the necessity? Well that certainly is debatable. However, the GC chip amps also have high PSRR and users there are now realising the benefits of proper regulation.
This amp will join my stable of Leach amps, Low Tim 3, Original Double Barrel (with the wings) both also fully regulated.
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