BTW: Somehow I doubt this, but is it possible to run multipliers in parallel to increase current?
You could potentially use parallel slave transistors to do this but then you might start to overload Q1. The whole circuit needs to be reexamined.
Also, the ancient Jean Hiraga from 'Audiophile (a magazine in France) said that the Darlingnot couple used will easily be prone to very high frequency odscillations.
I think it's a Sziklai complementary pair. From my reading I remember several articles that say poorly engineered Sziklai pairs can be unstable, but with proper attention to detail it's not an issue.
If anyone using this gets a small sound that is sorta like electrical farting it seems that too much capacitance after it will cause that. Not sure how voltage used will determine the capacitance that is too much. At 50v 1800uf was too much along with the circuits 200-400uf~.
Keantoken. I can't remember whether you had any more of the KM boards for sale or whether you were going to run off some more. I'd take 4 if you were sending out for more boards. Thx!
Hello keantoken,
I built up your k-mult according to attached circuit.
input AC is 15~16 VAC,, rectified to 22 VDC. follwed by lm317 , which is adjusted to 17 VDC output.
The k-mult further drops it down to 14.8VDC.
The led flashes and switches off at power-on. ( i could only see a faint single point glow of led, if i really see closely).
As soon as i connect a 1k load resistor ( about 16mA), the led switches on.
otherwise every component is ok ( resistors).
I have used bc327 / 337 and MJE15032/33 pair.
regards
Prasi
I built up your k-mult according to attached circuit.
input AC is 15~16 VAC,, rectified to 22 VDC. follwed by lm317 , which is adjusted to 17 VDC output.
The k-mult further drops it down to 14.8VDC.
The led flashes and switches off at power-on. ( i could only see a faint single point glow of led, if i really see closely).
As soon as i connect a 1k load resistor ( about 16mA), the led switches on.
otherwise every component is ok ( resistors).
I have used bc327 / 337 and MJE15032/33 pair.
regards
Prasi
Attachments
Try a higher load. IIRC I gave the output current range as 25mA minimum. For lower currents it doesn't always behave as expected.
Also, the capacitor ground connections should be in the same order as your schematic from left to right. Mixing them up can cause problems.
Also, the capacitor ground connections should be in the same order as your schematic from left to right. Mixing them up can cause problems.
thanks keen,
tried with a 500 ohm load, still same thing. grounding arrangement can be seen in the below image.
clean ground (317/337 and CMX share a common ground point near the leds.
rectifier and bulk caps are far upstream.
I will try replacing the 337/327 and see..
my load demand is quite low, ESP HPA. In that case will mje15033/32 pair be ok?
regards
prasi
tried with a 500 ohm load, still same thing. grounding arrangement can be seen in the below image.
clean ground (317/337 and CMX share a common ground point near the leds.
rectifier and bulk caps are far upstream.
I will try replacing the 337/327 and see..
my load demand is quite low, ESP HPA. In that case will mje15033/32 pair be ok?
regards
prasi
Attachments
That layout looks okay. I notice I didn't recommend the 15033/32 for the Kmultipliers. That is likely because I didn't have any to test, or if I did, they were not stable.
I would suggest finding a way to load the kmultipliers over 25mA, or switching to D44/45H11G. You can also try switching to BC5xxC for the TO92s, that has also worked before.
Just to make sure it is not another problem, please give me the voltage at each transistor pin.
I would suggest finding a way to load the kmultipliers over 25mA, or switching to D44/45H11G. You can also try switching to BC5xxC for the TO92s, that has also worked before.
Just to make sure it is not another problem, please give me the voltage at each transistor pin.
For everyone else: I do have Kmultiplier boards, but I got them from the fab without being cut apart, and I can't find my shears. Until I do, you'll have to get 4 at a time and cut them apart yourself.
Thanks kean, I will put them to good use in next project with recommended transistors ( an AKSA class A HPA) . meanwhile for this esp hpa , i built up a simple crc+lm317/337 as per Power Supply for Preamps , works fine for the purpose.
regards
prasi
Hi Keantoken, i want to use some sot223 transistor for space saving so can i use bcp53/56, pzta06/pzta56 in place of big transistor?
As long as the transistor can support the power dissipated, it is worth a try. If the transistor is not suitable you will have low PSRR or it may oscillate.
Prasi i was about to something very similar for my hp amp. I believe the original configuration was found in old parasound psu by john curl? My question is tho, since 317/337's max current output is 1.5a, does that influence the k multiplier's performance on where its current limit is set?
Keantoken, im debating on whether to use this or the typical darlington cmx for my class a headphone amp. Reading up on pros and cons of cfp vs darlington it seems to me that cfp is harder to stabilize vs darlington having more 2h, at least in the output stage. But also i remember seeing that the transistor characteristic of an active psu will show up on the load. Then since darlington has more 2h, can we assume that as a cmx the same characterstic will be heard on the final sound?
Since the D45H11 seems to be unavailable at present (like so many other parts): What other transistor do you recommend as a substitute?
