Dan, these are quite expensive, 270Euros including the charger!
That is what I said earlier to another member, it is a simple but not cheap amplifier, if you want the best performance out of it.
But... How much a PSU would cost with all these capacitors? (And it could never be cas lean as the batteries)
That is what I said earlier to another member, it is a simple but not cheap amplifier, if you want the best performance out of it.
But... How much a PSU would cost with all these capacitors? (And it could never be cas lean as the batteries)
Ah right, so connecting a small 1000uF electrolytic in parallel of each battery will solve this right?
I think the schematic of audiomanics does this on the PCB. Just replace the 47uF with a 1000uF one?
Here is the link
http://audio-constructions.com/monstre/hiragalemonstre.png
Elna Cerafine will do better than Mundorf?
I think the schematic of audiomanics does this on the PCB. Just replace the 47uF with a 1000uF one?
Here is the link
http://audio-constructions.com/monstre/hiragalemonstre.png
Elna Cerafine will do better than Mundorf?
well 1F = 1.000.000uF it's still too expensive and difficult to find and I am really not too much convinced if so big capacitance is needed in battery only operadion.
I think for battery only operation it is better to have a high quality capacitor rather than a big capacitor.
Let me propose another scenario and I would like your comments on this.
I have used cerafine elna caps in tube preamplifier with great success.
Their price is very cheap on ebay http://cgi.ebay.com/10-X-ELNA-CERAF...861131&_trksid=p3286.c0.m14&_trkparms=72:1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50
I was thinking of connecting some of them in parallel. In that way the total resistance of the psu (battery and caps) is minimised too.
The total capacitance will be something about 5000uF, which would be enough for this...?
I think for battery only operation it is better to have a high quality capacitor rather than a big capacitor.
Let me propose another scenario and I would like your comments on this.
I have used cerafine elna caps in tube preamplifier with great success.
Their price is very cheap on ebay http://cgi.ebay.com/10-X-ELNA-CERAF...861131&_trksid=p3286.c0.m14&_trkparms=72:1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50
I was thinking of connecting some of them in parallel. In that way the total resistance of the psu (battery and caps) is minimised too.
The total capacitance will be something about 5000uF, which would be enough for this...?
Neazoi,
There are two issues with audio power supplies.
#1 Ability to supply large currents very quickly with little sag, and
#2 Series impedance for earth return of speaker currents.
The first issue is pretty clear; to reproduce sharp transients, a low source impedance is needed, particularly at higher frequency. Bass frequencies are not so bad because they are slow, and SLA has very little sag at high current.
However, about 50% of the energy in music is above 500Hz, where the deficiencies of a SLA battery are significant. Midrange and top end, which are faster but lesser current draws. Bypassing the battery with quality film caps is very helpful here.
Issue #2: All amps with bipolar power supplies alternately use the + and - rail caps to form the return paths for the two circulating currents from rail, though output device, to speaker, to ground, and back to rail. Therefore a high ESR in this link will affect the speaker operation. While the ESR of the battery is very low up to 10KHz, beyond this it rises rapidly and can affect damping factor. Balanced against this is less requirement for damping with rising frequency, but for neatness it's a great idea to have high quality caps bypassing the 1000uF battery cap. Say something like a 22uF silver/oil Mundorf. If you are spending a lot of money on the supply, might as well go the whole nine yards and use a few nice caps for bypassing. For electros, use something like Black Gates, or Nichicon Muse.
Hope this helps,
Hugh
There are two issues with audio power supplies.
#1 Ability to supply large currents very quickly with little sag, and
#2 Series impedance for earth return of speaker currents.
The first issue is pretty clear; to reproduce sharp transients, a low source impedance is needed, particularly at higher frequency. Bass frequencies are not so bad because they are slow, and SLA has very little sag at high current.
However, about 50% of the energy in music is above 500Hz, where the deficiencies of a SLA battery are significant. Midrange and top end, which are faster but lesser current draws. Bypassing the battery with quality film caps is very helpful here.
Issue #2: All amps with bipolar power supplies alternately use the + and - rail caps to form the return paths for the two circulating currents from rail, though output device, to speaker, to ground, and back to rail. Therefore a high ESR in this link will affect the speaker operation. While the ESR of the battery is very low up to 10KHz, beyond this it rises rapidly and can affect damping factor. Balanced against this is less requirement for damping with rising frequency, but for neatness it's a great idea to have high quality caps bypassing the 1000uF battery cap. Say something like a 22uF silver/oil Mundorf. If you are spending a lot of money on the supply, might as well go the whole nine yards and use a few nice caps for bypassing. For electros, use something like Black Gates, or Nichicon Muse.
Hope this helps,
Hugh
thank you aksa, very informative.
That is why many constructions use good quality caps parallel to the electrolytics...
Based on your considerations it is better to parallel electrolytics too than using a big single one as the total inductance and impedance will be lower. That comes to a balance with the RF frequencies too where radio amateurs prefer to use parallel caps than single bigger ones. (ok compensating for temperature coefficients is an issue there too)
That is why many constructions use good quality caps parallel to the electrolytics...
Based on your considerations it is better to parallel electrolytics too than using a big single one as the total inductance and impedance will be lower. That comes to a balance with the RF frequencies too where radio amateurs prefer to use parallel caps than single bigger ones. (ok compensating for temperature coefficients is an issue there too)
For an 8W amplifier, you would only need around 1000uF as coupler anyway (8R at 20Hz Xc and very limited current, around 11.3Vpeak, or 1.41A into an 8R speaker), and this is the reason I do not overspecify. You can certainly use more than this if you want, but taking account of the premium quality it gets expensive, particularly if you use 10,000uF.
I use only 1800uF coupler for a 28Wrms amp, and it's fine down to 25Hz. Best not to go overboard, particularly as a battery has very strong current delivery at low frequencies. It's essentially the higher frequencies which are significant, here.
Cheers,
Hugh
I use only 1800uF coupler for a 28Wrms amp, and it's fine down to 25Hz. Best not to go overboard, particularly as a battery has very strong current delivery at low frequencies. It's essentially the higher frequencies which are significant, here.
Cheers,
Hugh
in latest "batch" of several Fx Pass amps built in collaboration on one local Serbian forum , I introduced use of motor run caps , as final "bypass" ones ;
Icar Ecofill 50uF were used , and results are so satisfactory that everyone says that they're certainly "must have " in each future project
off course - more , the merrier
Icar Ecofill 50uF were used , and results are so satisfactory that everyone says that they're certainly "must have " in each future project
off course - more , the merrier
Zen I have used motor PIO caps at my tube preamplifiers PSU. they are cheap, 5% tolerance and PIO. I do not see any reason that someone could not use these, although since I have no exact specs I would go for a more generally acceptable (and expensive) solution. But not the super high prices of audio notes, it seems too much to spend for such "high fidelity" claimed parts just for PSU..
neazoi said:
AKSA said:
yeah , old story for old geezers
........believe me - decent motor-runs ( Icar is old and certainly reliable company ) are comparable and even better than FiFi Product of Week items ....... at least in PSU usage ...... but that fact is probably also old story for same old geezers
I have nothing against Mundorf and likes , but I feel strong passion for saving few greenies on caps and use them for more music
edit , for my greek friend :
if some gain stage is so dependable of PSU filter quality ....... than that PSU filter is of same importance as cap in signal path ........
anyway - every amp is doing nothing more than modulating PSU across speaker as load ...
testing le monstre
Dear Hiraga people,
I just finished one board with original components, but i did not have the big caps powersupply. I am curious about the sound. Is it a problem to test the amp for a minute with my small laboratory power supply +/- 14. 3 volts with total 12.000 uf caps? what will happen without big heatsinks for the output trannies and the 1ohm 5 watt resistor?
Thank you,
Regards,
Josh
Dear Hiraga people,
I just finished one board with original components, but i did not have the big caps powersupply. I am curious about the sound. Is it a problem to test the amp for a minute with my small laboratory power supply +/- 14. 3 volts with total 12.000 uf caps? what will happen without big heatsinks for the output trannies and the 1ohm 5 watt resistor?
Thank you,
Regards,
Josh