I was wondering if I could get some help choosing Caps for Prasi's Compact Apex FH-9 XRK Mod amplifier board?
The Nichicon electrolytic caps I wanted to use are on backorder for ever and I was wonder would would be good second or third choices?
As for the ceramic and film cap choices, they were just my best estimates based on what I have been reading around the site.
Any suggestions for better film and ceramic cap options?
Space restrictions are rather tight,
Schematic to see where they go,
If you want to see them on Mouser,
*** Here is a link to the cart ***
Also, either my sight is worse than I thought, or R26 resistor and the LED have been deleted from the compact board.
For the SMD caps C16 and C17 on the back of the board, what values are supposed to go there?
The KSC1845FTA seem to be sold out everywhere, is there a decent alternative?
Or do I just have to wait 6 months for them?
Thank you,
David.
The Nichicon electrolytic caps I wanted to use are on backorder for ever and I was wonder would would be good second or third choices?
As for the ceramic and film cap choices, they were just my best estimates based on what I have been reading around the site.
Any suggestions for better film and ceramic cap options?
Space restrictions are rather tight,
Schematic to see where they go,
If you want to see them on Mouser,
*** Here is a link to the cart ***
Also, either my sight is worse than I thought, or R26 resistor and the LED have been deleted from the compact board.
For the SMD caps C16 and C17 on the back of the board, what values are supposed to go there?
The KSC1845FTA seem to be sold out everywhere, is there a decent alternative?
Or do I just have to wait 6 months for them?
Thank you,
David.
There is an ebay seller eizner23 that has stock of the ksc. In the US aswell.
Fairchild KSA992 + KSC1845 complimentary pair transistor combo 20pcs | eBay
Fairchild KSA992 + KSC1845 complimentary pair transistor combo 20pcs | eBay
Can someone confirm that schematic by prasi is the latest one and also suited for HV xrk version? Is there any impornat difference between them?
As far as caps , except input cap of 3.3u, others can be general purpose film caps.
For electro, use good quality for C5, others caps can be from nichicon VR or similar
ceramic to be NP0/C0G 100V
Last edited:
Dave/Fred,
Would you be able to guide me as to which post you're finding the BOM for this particular version? I've been on the hunt for the better part of an hour and haven't had any luck.
Thanks,
Kellis
To the best of my knowledge there is no official BOM for Prasi's single channel Apex FH-9 XRK Mod amplifier board.
I have stumbled along and tried to make a BOM, but I am not sure about some of the caps...
Link to Mouser Cart
View attachment DaveFred Sept30-2021 Apex FH-9 XRK Mod Mouser BOM guess v0.1.pdf
Zipped Excel
View attachment DaveFred Sept30-2021 Apex FH-9 XRK Mod Mouser BOM guess v0.1.zip
I have the boards, just not the confidence in my picks to place the order and build them.
David.
hello forum members, has anyone set up the Apex tb7 or tb10 tone control? I set up Apex TB1 together with Tb3, the sound quality is great, but I need more tonal controls and I'm wanting to set up the tb7 or tb10, but I would like to know the opinion of someone who has already set them up. Thank you Mr Mile Slavkovic for giving us these great projects, soon I'll post the photos of my set to share.
David,
Thanks for posting your BOM - it looks like a great starting point. The PCBs I ordered came in so I was able to take some measurements (in inches first using a pair of calipers, then converted to mm, so perhaps not exact...) and most of the parts seem like good choices. There seem to be a couple missing / mislabeled resistors, and your chosen C5 was too small of a value, but perhaps we are looking at different versions of the schematic. One issue I did see was that the SMT resistors on your original BOM are too long for the solder pads on the rear of the PCB - I've added an updated link for these and a few other items in the attached BOM (see the "updated" sheet) and included Prasi's schematic which I was using as a reference. Hopefully that is useful...
Regarding the output inductor, does anyone have any info on its construction?
Thanks,
Kellis
The FH9 is an all around great amp, but particularly its bass is very good. If it was the last amp I had, I wouldn’t be unhappy. There is the 100w FH9 (HV or high voltage) variant with high quality components and BOM is circa $35 per channel on Mouser. That one can use rails up to +/-53v. But it works well at +/-35v too.
If you are having a hard time finding KSC1845’s try BC546 or 2N5551. Just twist the legs to the appropriate pin out. For outputs, I prefer the sound of the Fairchild FQA’s. They also handle more power than IRFP240/9240.
Last edited:
