buy new leaded Sn Tin 63%/Pb lead 37% eutectic with 1% or 2% flux built in. It melts and freezes @ 183°C with no pasty phase.
I have added the [63/37] to clarify the meaning of the last sentence.
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Hi X, I have spare time this weekend to build FH9. I did a quick read from page 650 until last page, and I still can not find guidance about how to set bias for FH9. Could you help me ? I currently have BD139 and 140, so I will start with FH9 first.
Hi, I don't know how to set bias current for FH9 amplifier. sorry for newbie question, wish someone will help me. Thanks
What is the DC level that triggers protection? Also what is temperature that fans come on based on NTC and is that temp adjustable?
Measure voltage across one of the big power resistors with a DVM. Adjust the bias trimpot (1 of 2 and one near the middle next to BD139) and measure voltage across the 0.47R (2 in parallel so R effective is 0.47R/2). Adjust between 80mA and 200mA. 150mA is a good trafeoff beyween heatboutput and low distortion). Other pot adjust to get 0vdc at output terminal.
Hi sir Apex do you have the pcb for TB2? I want to make it for my F100 amplifier. Thanks.
An externally hosted image should be here but it was not working when we last tested it.
Mr. Miles, will i be ok to use +/-48V PSU on AX-11 bimo mod with Sanken o/p devices. what other transistor needs to be changed?
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-828.html#post4794009 .
sch attached. can i simply replace Q1/Q3 and Q7 with higher voltage capable transistor like 2N5551 with legs bent/ reversed ?
i will never use this amp at full power. are there any other components that need upgrade other than voltage capacity like resistor values and wattage, etc..
i have a 35-0-35vac trafo. and that is the only transformer i have available right now😱.
reg
Prasi
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-828.html#post4794009 .
sch attached. can i simply replace Q1/Q3 and Q7 with higher voltage capable transistor like 2N5551 with legs bent/ reversed ?
i will never use this amp at full power. are there any other components that need upgrade other than voltage capacity like resistor values and wattage, etc..
i have a 35-0-35vac trafo. and that is the only transformer i have available right now😱.
reg
Prasi
Attachments
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thank you Mr. Mile for answers.
Will build this amp for a DIY subwoofer using Dayton 8" DVC (dual voice coil) driver connected in 4 ohm configuration.
will be careful not to exceed i/p voltage to more than 0.62V as this amp has i/p sensitivity for full power 1.13V.
The two input transistors and the two drivers are both rated correctly for ±35Vdc
But both will be overloaded when changed to ±50Vdc.
Please change:
Q5 = 2SA1381
Q6 = 2SC3503
Q8 = 2SC5171/2SC4793
Q9 = 2SA1930/2SA1837
Q1 and Q3 = 2SC1845
It may improve it.
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Hi Bimo,
Thanks for your suggestion. I am not looking so much for improvement but for replacement components that can sustain the +/-48VDC PSU. Also 1381/3503 and 4793/1837 are not available with me right now. I do have many MJE15032/33 for Q8 and Q9. can I use those?
ofcourse even with sanken 2SA1216 /2SC3264, I wont drive it to clipping level. its just for small home HT set-up.
reg
Prasi
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these are much lower fT than genuine BD devices.
34/35 are slightly faster, but still nowhere near BD speeds.
Here is what i would like to do.
1. Q1/Q3 2N5551 with orientation opposite to silk, as it is handy at the moment.
2. Q5/Q6 (EBC)- I may have KSA1381 and KSC3503. will try and see. or as Mr. Mile suggested use 100R or even 150R for R12/16.
3. Q8 and Q9- MJE 15030/31 orientation opposite to silk.
I want to use small to-220 PCB mount heat sink for drivers (MJE15030-31). will it be sufficient? this will help in avoiding leg twisting due to differences in pin between BD139/140 and MJE15030/31.
i want to use whatever is available right now rather than order new components for a quick build.