10uF is a bit low feeding these trafos. What it will do is give you a bass boost, if you don't mind that then no need to worry. I'd suggest using an electrolytic of 100uF or larger to get a reasonably flat bass response.
Its available soon yes with the caveat that we aren't guaranteeing the inductors are actually made by Coilcraft. Their specs will be very close to the Coilcrafts though.
Unfortunately driving a 4ohm load isn't just a matter of changing the output L and C. There's the knotty matter of 4ohms needing twice the current of 8ohms - which will be beyond the regulator's ability to supply. If you're content to reduce the output power by 50% then lower inductors (say 10uH) and larger caps will match the impedance OK. I'm not sure if larger caps will fit on the same footprint though.
The 200mA limit would be fine in this application, only the TDA8932's signal stages are fed from this regulator, the typical current is 40mA or so, max 50mA. Yes long wires will increase inductance (and DCR) so shorter is better. There is a cap nearby though.
In substituting a reg its important to pay attention to the output voltage - if this goes higher than the power stage rail, the protection diode will conduct and that'll current limit the regulator when music is playing. So better to set the signal rail voltage a little bit lower than the power rail voltage (typically that's around 21V).
Recently stumbled on another of Mark Johnson's designs. I saw his low current SMPS filter on angchuck's build.
Here he has a regulated higher current affair that uses comparable regs to U4.
It has a 2v drop.
Though it interesting enough to share.
Which keeps reminding me I must finish my boards!
Richard would you be in a position to sell SMD pre populated rev5 boards as per your pic above?
Here he has a regulated higher current affair that uses comparable regs to U4.
It has a 2v drop.
Though it interesting enough to share.
Which keeps reminding me I must finish my boards!
Richard would you be in a position to sell SMD pre populated rev5 boards as per your pic above?
You mean minus all the other parts in the kit? I'm sure we can work out a price for that, so long as you don't need a BOM for all the missing parts.
Yes just as is in that photo. BOM not required! Would save me a chunk of time on SMD assembly as id really like to listen to this amp!
I'm curious why a complete kit is less interesting to you than the almost-bare board alone? Do you have a ready source of parts cheaper than we buy here in China? Or you want to trick it out with boutique bits? If the latter then desoldering some of the resistors already put down is going to be a bit of a pain.
I have the output inductors, and the Ali/taobao input trafos here so I thought I'd be saving some money but if a kit isn't much more then I'm happy to go with that . The main draw for me is the time saving on the SMD pre pop.
I'll PM you shortly!
I'll PM you shortly!
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Yeah you would save some money as PCBs are quicker to pack than kits. If you went ePacket the reduced weight would mean slightly lower shipping costs but with courier there's a minimum 500g so those charges wouldn't change. You're unlikely to want the delay and uncertainty of ePack though. We can just pull out the trafos and output inductors and that'll reduce the price of the normal kit a bit.
Quick review:
Source: Topping Dx3
Pre: Kb1 with 10uf silmics, 100k pec pot.
Speakers: Fugelhorn
Music: Disney/Netflix/Youtube
Amp has a really low floor noise. This allows great soundstaging. I can hear new details in Disney programs that my daughter has me watch along with her. I guess that's my secret entertainment.
As Richard mentioned, 10uf into the amp, gave me a nice bass boost, even when the speakers were not optimally placed. My perfect combination for a budget friendly system, using cheap aliexpress smps.
I'd remember some 20 years ago when I thought I heard my dream system, a Tact Class D and some Joseph Audio Floorstanders. This Transformer-fed TDA8932 combination gives me shades of those fleeting memories.
Richard, I would be happy to try one of your dacs soon!
I have other diy setups combinations, but this my current fav.
Source: Topping Dx3
Pre: Kb1 with 10uf silmics, 100k pec pot.
Speakers: Fugelhorn
Music: Disney/Netflix/Youtube
Amp has a really low floor noise. This allows great soundstaging. I can hear new details in Disney programs that my daughter has me watch along with her. I guess that's my secret entertainment.
As Richard mentioned, 10uf into the amp, gave me a nice bass boost, even when the speakers were not optimally placed. My perfect combination for a budget friendly system, using cheap aliexpress smps.
I'd remember some 20 years ago when I thought I heard my dream system, a Tact Class D and some Joseph Audio Floorstanders. This Transformer-fed TDA8932 combination gives me shades of those fleeting memories.
Richard, I would be happy to try one of your dacs soon!
I have other diy setups combinations, but this my current fav.
Which kit has the lowest smd part counts to solder? I almost need reading glasses now.
I think the kit with the fewest SMD parts to solder would be Phi DecaDAC MkII. Its an older design nearing the end of its life now.
You could always get a built-up DAC if your eyesight's on the blink. I'm hoping Abbado will be the entry level for ready-built DACs eventually, but its at the prototype stage with a redesign to eliminate the opamps. That means its still a few weeks out.
Glad to hear you love the amps!
You could always get a built-up DAC if your eyesight's on the blink. I'm hoping Abbado will be the entry level for ready-built DACs eventually, but its at the prototype stage with a redesign to eliminate the opamps. That means its still a few weeks out.
Glad to hear you love the amps!
Jim - C38 isn't fitted when you're soldering R17 in. C40 is. I've updated the build guide (thanks to wifey for the artwork) in the first post now, it's based on r5.
Oh I forgot - when using a shunt you also need to remove R15. If not, it'll smoke and remove itself from the circuit.
I managed to remove the R15s fairly easily, a bit tight when the shunts and caps are in place but no harm done.
I also inadvertently 'removed' one of the big Coilcrafts. Don't leave your 'projects' in the boot of your car...forget....and go for a spirited drive in the country!
Ripped the pads off but I managed to mend it with copper tape. I've measured over and out of the coil and it has the same DCR as the original trace so I think the fix is adequate.
Nearly have 4 made up now so hopefully will be giving them a listen soon.The green boards are bare boards that I had made with gerbers. Steady old job populating those! I have had good results with a Traco power 100w SMPS. I have (had) a bit of an aversion to SMPS but I got these cheap enough mainly as simple test PSUs. I used one per channel on a recent Pass ACA build and I have to say they were silent. I measured the AC ripple just with a RMS DMM and I think it was below what it could read . So I'll try them with Mark Johnson's SMPS filter into these amps. I also want to try a CapMx.
I also inadvertently 'removed' one of the big Coilcrafts. Don't leave your 'projects' in the boot of your car...forget....and go for a spirited drive in the country!
Ripped the pads off but I managed to mend it with copper tape. I've measured over and out of the coil and it has the same DCR as the original trace so I think the fix is adequate.
Nearly have 4 made up now so hopefully will be giving them a listen soon.The green boards are bare boards that I had made with gerbers. Steady old job populating those! I have had good results with a Traco power 100w SMPS. I have (had) a bit of an aversion to SMPS but I got these cheap enough mainly as simple test PSUs. I used one per channel on a recent Pass ACA build and I have to say they were silent. I measured the AC ripple just with a RMS DMM and I think it was below what it could read . So I'll try them with Mark Johnson's SMPS filter into these amps. I also want to try a CapMx.