Hi Sonal,
Thanks for your reply. I live in Pune city. I will try to find out if the transistors are available here.
Also pl answer following questions
1. capacitor 104 (100nF) connecting signal ground and supply ground present on layout and not in schematic and unconnected in the amp photo. should use this capacitor or not?
2. R15 is written twice in the schematic . Pl see attachment of post #274.
3. there are some discrepacies in the values of resistor as mentioned in the parts list and on PCB layout. (e.g. R18: 82R in layout and 220R in parts list.
Here is what I will do. I will prepare the PCB layout as per APEX layout and share it with you. Would you be kind enough to check it for any errors?
reg
prasi
Hi Sonal,
Pl find below apex D14 kelvin amp pcb with TIP141/142. Supply voltage +/-45V. rest of the components and their values are as per original apex layout. would you be kind enough to tell me if there are any errors?
regards
prasi
PS: I have made a larger pcb (100x81 versus original 82.5x62.5) as my soldering skills are awful and dont want to short different pads/tracks.
Attachments
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Attachments
Hi Prasi, use 10R/1W resistor to connect power ground to signal ground parallel with 100nF capacitor. Look at image posted, I have used it on all of my Apex NX and AX series amps I have made.
There is lots of space on pcb, add zobel to output of amp. Use 4R7/2W in series with 100nF capacitor.
Regards,
Sonal
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Hi Sonal,
Thanks for your reply and inputs. I have modified the board accordingly and attaching the PCB. I have connected the zobel across amp output and gnd.
reg
prasi
Attachments
Dear Mile sir,
Thanks for the compliments!. Do you have any comments on the revised PCB attached with Post # 286 which includes a zobel on the o/p and parallel cap and res between signal ground and supply ground?
reg
prasi
Hi sonal awaiting your reply on the modified layout before I buy components and etch the PCB.
Reg
Prasi
Hi Sonal,
Thanks for DRU file. I checked my PCB with sparkfun.dru and no errors. However, as suggested by you I will go with larger pad sizes for all res/cap/power res/transistors.
thanks again.
reg
prasi
Hi Anjan,
thanks for extending your assistance. I am currently occupied with building a diy apex gainclone amp and tone control. when i start building D14 amp i will get in touch with you.
Hi Sonal,
Have a doubt in the layout prepared by me and the amp photo attached by Apex (post no.31, http://www.diyaudio.com/forums/solid-state/163159-150w-mosfet-amplifier-irfp250x2-4.html).
I have made the PCB layout as per schhematic of apex , but Orientation of Q6 BC557 is reversed on the photograph posted by APEX in the above link.
can you confirm, which is correct?
I have attached pics of both circling the difference.
regards
prasi
Have a doubt in the layout prepared by me and the amp photo attached by Apex (post no.31, http://www.diyaudio.com/forums/solid-state/163159-150w-mosfet-amplifier-irfp250x2-4.html).
I have made the PCB layout as per schhematic of apex , but Orientation of Q6 BC557 is reversed on the photograph posted by APEX in the above link.
can you confirm, which is correct?
I have attached pics of both circling the difference.
regards
prasi
Attachments
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Hi Sonal and others,
i am attaching herewith my apex kelvin amplifier build . i just need clarification on the MJE350 and MJE340 orientation. whether i havemounted correctly?
As suggested by you earlier, the power ground and signal ground are seperated and also a zobel is incorporated on the amp pcb itself.
reg
prasi
Attachments
Hi prasi,
MJE350 and MJE340 orientation are ok but heat sink is small for this amplifier. You should check http://diycomponents.in, http://diyaudiocart.com and http://www.gajsupply.com for heat sink.
Regards,
Sonal Kunal
MJE350 and MJE340 orientation are ok but heat sink is small for this amplifier. You should check http://diycomponents.in, http://diyaudiocart.com and http://www.gajsupply.com for heat sink.
Regards,
Sonal Kunal
Hi Sonal,
Thank you for your reply. I have already mounted the pcb on the heatsink that i had. I will just test the amp pcb for its operation and then I will order the new bigger size heat sink as suggested by you from the website. Can I mount both PCB's side by side on a 200-230mm heat sink for stereo application? I am also planning to put a processor fan at the back of amp for extra cooling.
Also kindly answer my following query.
1. How is the bass response of the kelvin amp that you built. I have built the APEX lm3886 and feel that bass is bit lacking ( as compared to SC 301 | astonia audio). Its a soild state amp that has good review on AVmax magazine and sound is amazing , especially the bass. May be they have boosted the bass. Dont know really. May be apex lm3886 is very neutral with a flat frequency response approaching true hi-fi (whats recorded is what should be heard)
reg
prasi
Thank you for your reply. I have already mounted the pcb on the heatsink that i had. I will just test the amp pcb for its operation and then I will order the new bigger size heat sink as suggested by you from the website. Can I mount both PCB's side by side on a 200-230mm heat sink for stereo application? I am also planning to put a processor fan at the back of amp for extra cooling.
Also kindly answer my following query.
1. How is the bass response of the kelvin amp that you built. I have built the APEX lm3886 and feel that bass is bit lacking ( as compared to SC 301 | astonia audio). Its a soild state amp that has good review on AVmax magazine and sound is amazing , especially the bass. May be they have boosted the bass. Dont know really. May be apex lm3886 is very neutral with a flat frequency response approaching true hi-fi (whats recorded is what should be heard)
reg
prasi