Juma's Head Amp

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#21
CeeVee said:
Listen to Juma...think of EUVL...


it's public
Publish the gerbers....don't make a big deal of it.


...upon request....come on....anyway it is way different from the original....share ...recognize the gift EUVL gave you.
Click to expand...

How about recognizing my gift😉, I have published both the exact schematic (post#6) and also the layout (post #8)... I am not asking anyone to pay for the gerbers, as already 3 people have got the gerbers. if one is too lazy to drop a PM or its a "big deal" to them, sorry i cant help...
 
#30
xrk971 said:
Funny - I always thought you did layouts with Sprint. Regardless, they are excellent and we appreciate your generous spirit in giving us the Gerbers. I can't wait to make this amp. I may use it more as a preamp.
Click to expand...

Yes, always have been using Eagle, sprint is easy but needs lot of manual checking and eagle (bird) eyes.
I must appreciate your energy, always impatient to try new things!
reg
prasi
 
#33
e_fortier said:
PCBs ordered ;-) Thanks Prasi !

To maximize SQ of this design, which components should we be focusing on ?

Thanks,
Eric
Click to expand...

Hi Eric,
BC550/560 pair would lower the noise, Also the pots (P1,P2) control Iq of the ckt. Sim shows, with lower resistance setting of the pot and hence higher Iq, distortion decreases. Juma recommends 50-100mA.
reg
Prasi
 
#34
Thanks Prasi.

Since your Juma HA PCB is very small (50mm x 50mm) I was thinking of building a 'small' headphone amp. I already have a 30VA toroidal and some +/- voltage regulators but all this makes the HA enclosure too big for my taste. I'm looking for a different approach.

Do some of you know the TPS5430 from TI ?? There is a small (50mm x 50mm) PCB on e-bay (see link below) that takes a single polarity DC input, lets say 19Vdc and converts it to +/- 15Vdc (by changing 2 resistors). This would reduce the size of the HA enclosure by a large margin. Also, no mains going into the enclosure, the whole HA could be powered by a single 19Vdc laptop power supply, just like the one from the ACA power amp.
The TPS5430 works at a fix 500KHz. I couldn't find if it's noisy but one of the application stated in the spec sheet is Pro audio mixer so looks OK for audio product I guess...?

NEW TPS5430 Positive Negative Dual Power Supply Module with Switching | eBay

Any feedback about my idea is welcome..positive or not ;-)

BR,
Eric
 
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#35
e_fortier said:
Thanks Prasi.

Since your Juma HA PCB is very small (50mm x 50mm) I was thinking of building a 'small' headphone amp. I already have a 30VA toroidal and some +/- voltage regulators but all this makes the HA enclosure too big for my taste. I'm looking for a different approach.

Do some of you know the TPS5430 from TI ?? There is a small (50mm x 50mm) PCB on e-bay (see link below) that takes a single polarity DC input, lets say 19Vdc and converts it to +/- 15Vdc (by changing 2 resistors). This would reduce the size of the HA enclosure by a large margin. Also, no mains going into the enclosure, the whole HA could be powered by a single 19Vdc laptop power supply, just like the one from the ACA power amp.
The TPS5430 works at a fix 500KHz. I couldn't find if it's noisy but one of the application stated in the spec sheet is Pro audio mixer so looks OK for audio product I guess...?

NEW TPS5430 Positive Negative Dual Power Supply Module with Switching | eBay

Any feedback about my idea is welcome..positive or not ;-)

BR,
Eric
Click to expand...
I am somewhat removed from civilization with limitd connectivity. I do not have any idea abt TPS5430, someone who actually has built one could comment.
reg
prasi
 
#36
I think you have a couple of options. Get two 19v SMPS (small netbook ones) and hook in seriesfor +/-19v power supply. Or get a buck converter and tie two of them from single 19v supply and then put them in series for plus minus supplies. These need to be voltage isolated buck converters otherwise cannot be out in series.

I don't know if these will work - needs to be isolated.

https://m.nl.aliexpress.com/item/32...-1476840504220-08151-rbMv3Fyb6&aff_platform=y
 
#40
e_fortier said:
Thanks Prasi.

Since your Juma HA PCB is very small (50mm x 50mm) I was thinking of building a 'small' headphone amp. I already have a 30VA toroidal and some +/- voltage regulators but all this makes the HA enclosure too big for my taste. I'm looking for a different approach.

Do some of you know the TPS5430 from TI ?? There is a small (50mm x 50mm) PCB on e-bay (see link below) that takes a single polarity DC input, lets say 19Vdc and converts it to +/- 15Vdc (by changing 2 resistors). This would reduce the size of the HA enclosure by a large margin. Also, no mains going into the enclosure, the whole HA could be powered by a single 19Vdc laptop power supply, just like the one from the ACA power amp.
The TPS5430 works at a fix 500KHz. I couldn't find if it's noisy but one of the application stated in the spec sheet is Pro audio mixer so looks OK for audio product I guess...?

NEW TPS5430 Positive Negative Dual Power Supply Module with Switching | eBay

Any feedback about my idea is welcome..positive or not ;-)

BR,
Eric
Click to expand...

The eBay board is 5v output. Can it be changed? Maybe, but it's all smd. And it only has 470uf of capacitance. So, without additional caps you will be extremely undersized in PSU.

This appears to be a switching regulator. I was wondering how it's able to regulate 2 amps with no heatsink.

I don't know much about these but it's not something I would try or recommend. It's probably intended for digital circuits (hence the 5v) and by the time you add enough capacitance you will lose all the size advantage.

If you are looking for small, I would probably recommend an ic based ab or class d design.
 
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