You do realize that you are showing the graph for the modular application?The transformer 300VA can deliver 8,33Amps each rail so its could be a stable rail i guess.
the SOA diagram shows more voltage possible at 4R. the heat dissipation should not exceed 50W at 4R.
so my 18VAC trani should be changed tho 24 - 0- 24 VAC
chris
(this is 2x TDA7293 in parallel). This is obviously different.
2x18VAC seems pretty good to me for a 4Ohm speaker.
I wouldn´t go above 2x22VAC as it will be difficult to cool the chip when driven hard.
Is there an updated revision planned, or maybe something like a parallel version?
Asking cause I´m in the market for 2-4 PCBs and thinking of ordering some at JLCPCB. (would order 10pcs. if anybody in the EU is interested)
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yes you are right! ST datasheets are "different"
i know the TI LM1875 + TPA3250, TPA3255 datasheets as well and its really well done.
chris
Be careful with the Mouser project in post#1. It has not been updated with changes that evolved since then. But it is a good starting point.
The BOM listed in post #186 is the latest that I know of, but it too is no longer current.
I have now worked through these and assembled my Mouser project incorporating accumulated changes in this thread, and I could post it, but have one issue - the matching of headers, housings and contacts. The mentioned BOM or project does not list the parts that go with J1, J2 and J3.
I think I’m Ok with J1 and J3, but I’m unsure about J2, especially the contacts. What I think would work is sold only in quantities of 100 by Mouser. It is only $3.20 for the lot, but I don’t know if they would work.
https://www.mouser.com/ProductDetail/538-08-50-0113-CT/
Could someone who built it already comment on these. How did you do the connection to J2.
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A quick note on TDA7293V availability. Go and get them now!
I ordered mine from Arrow and I just noticed that there are 16 left in inventory. It has been reported that both Mouser and Digikey are out with long lead times.
https://www.arrow.com/en/products/tda7293v/stmicroelectronics?q=TDA7293V
Btw, Arrow website stated country of origin was Marocco. Is that where they are all made?
I ordered mine from Arrow and I just noticed that there are 16 left in inventory. It has been reported that both Mouser and Digikey are out with long lead times.
https://www.arrow.com/en/products/tda7293v/stmicroelectronics?q=TDA7293V
Btw, Arrow website stated country of origin was Marocco. Is that where they are all made?
The BOM in post #186 is fine. C10 has been suggested to be increased from 220pF to 680pF.
For J1, the matching piece is (from Digikey) either WM23702-ND (molex #0039012060) or WM23702-ND (molex #0039012065)
For J3 the matching piece is (from Digikey) WM3701-ND (molex #0039012040).
The insert (crimp) pins for the two connection receptacles (just mentioned) is (Digikey) WM2501-ND (molex #0039000039) if you want to mount 18-24AWG wire OR (Digikey) WM10851-ND (molex #0457503112) for mounting 16AWG wire.
Or, has someone has already mentioned, you can use old PCI-E 6 prong connectors and the 4 prong connectors from old computer power supplies if you have the laying around. Make sure you ignore the color coding on the wires as it doesn’t match up to the amp’s pins. Molex also sells pre-assembled connectors (with different gauges of wire) complementary to J1 & J3 with different lengths of wire already to go (cost more $).
For J2, a matching connector is (from Mouser) 538-10-11-2023 (molex #10-11-2023) while the pin inserts are 538-08-65-0816 (molex #08-65-0816). I already had these from Mouser which is why I didn’t give you a Digikey order #. I just went into Molex’s website and cross-checked everything.
X - do you confirm these part numbers?
Cheers,
Pete
Did you only ruin the solder pads on the underside of the board or on both the top & bottom? If only on the bottom you could just mount U2 & U3 from underneath and solder on the top. Just check continuity with the undamaged pads with the PCB holes that lead to pins 1,2 and 3 of both. If you mount from underneath you'll also have to be careful of pin # versus hole # obviously.
Cheers, Pete
I meant to add a suggestion that you post some pictures. Perhaps the boards could be rescued.
Thanks turion64 for those checks on the connectors.
“Issues” with the post #186 BOM that I noted while reading the thread were:
1. C10 increased to 680pf. I believe you also suggested to have a 470pf.
2. R20 (100k) is not on the BOM.
3. A 10pf is to be soldered in parallel to R1.
4. R15 is reduced to 10k.
5. The wire housings and connectors, and Thermal pad were probably omitted intentionally, but I put them in my project.
Have I missed any? If so please let me know. After I sorted out the J2 connectors I could post my Mouser project.
R20 is on the BOM sheet that I have.. Hmmm
Only change R15 (from 47.5K to 10K) if the DC offset is higher than 5-8mV DC. I have two builds and 47.5K worked fine on one build while i had to go to 10K on the other build.
The 10pF across R1 is from one gentleman's observation so whether it's necessary on everyone's build is still up in the air. I can't hear any difference with it on or off to tell you the truth ;>)
Pete
Only change R15 (from 47.5K to 10K) if the DC offset is higher than 5-8mV DC. I have two builds and 47.5K worked fine on one build while i had to go to 10K on the other build.
The 10pF across R1 is from one gentleman's observation so whether it's necessary on everyone's build is still up in the air. I can't hear any difference with it on or off to tell you the truth ;>)
Pete
Long story, short version. Transistor broke off while trying to desolder. I got impatient, tried to drill out the solder & leads. Paid the price. I have already desoldered about 2/3 of the components. Will test them all before using them again. Good news is that I have an opportunity to pick up a couple of boards from a kind member. Live and learn.
MM
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