Is the first time I try AX-14 Terry and I'm really happy with the results, about the drivers I think I have seen guys using different drivers transistors, I myself decide to use the ones that are in the schematic and the good thing is that they are all plastic so one less worried about insulation just a bit of thermal paste and good to go, but I guess other driver can be use I think I have seen here is a post about driver transistors the "best ones" about cutting just try not to cut the BD139 traces 
take your time
yes me too I want to try TO-3 devices too that will be next
Regards
Juan
take your time yes me too I want to try TO-3 devices too that will be next
Regards
Juan
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did you use a coil and a 10R ? mine was unstable I notice it was getting hot, after I place the L1 20 turns of 18AWG wire +10R all went to normal that is what I did maybe you case is different I just want it to mention that
Regards
Juan
do you have at least 1nF maybe you can put some in parallel under the board I mean that will give about 2nF, in my boards I have 1.5nF 100V,
I forgot to tell you to initiate the board I read here that C7 that is in parallel with the NFB R11 22K need to be 330pF for test then after is stable and bias set then you can changed it to 47pF as I did the bias I decide to go to what is recommended so I adjusted to 15mV reading from R24 0.33 my power supply delivers 53V DC so is just right
let me know how it goes also don't forget a GND wire from the power supply 0V to the RCA GND connection see imagesthe last image is to let you know to insulate the top of the PCB if you are going to use " L" adapter
Regards
Juan
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Hi Terry, any combination that will sum up close to 1500p, being put in parallel. Like 1n + 470p, 3 x 470p, etc. will be fine for testing.
Hi John'
I can take some pictures when I get home from Church today. I built the first one with TO-3 transistors for the fun of it. I have a bad offset on one channel. I have to track it down. I didn't listen to music yet but the scope looks very good on the channel that is working..
Blessings, Terry
I can take some pictures when I get home from Church today. I built the first one with TO-3 transistors for the fun of it. I have a bad offset on one channel. I have to track it down. I didn't listen to music yet but the scope looks very good on the channel that is working..
Blessings, Terry
Hi Terry,
Can we see your board
I think I will made AX-14 again with my new boards
yeah man you should try out AX-14 it sound amazing good respond to tight bass and vocals are nice I love it
I have a power supply board almost ready, up to 44000uF with many size option caps next projectRegards
Juan
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I had a few minutes before church so I took some pics. I'll show working channel on the left and troubled channel on the right. Maybe one of you eagle eyes can spot the trouble.
Thanks, Terry
EDIT; FIY I have about three volts shy of negative rails on the collector of Q9. Should be about -1.2v
Thanks, Terry
EDIT; FIY I have about three volts shy of negative rails on the collector of Q9. Should be about -1.2v
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that small blue package looks like a high K ceramic.Terry this is the part number 490-7574-1-ND for the 1.5nF 100V they are really small
Juan
It is too small to be a C0G/NP0
I don't recommend a HiK for coupling duty and absolutely against it for filtering duty.
Terry look great
hey I have problems the first time I put it together because some how the holes for the TO-3 has some solder residue and it was touching the heat sink, so what I did I insulated "temporary" the top of the PCB and problem went away, also you can use a large drill bit and scrape of some material to avoid that contact with the heat sink I did a quick "ghetto" fix with tape also move the pot to the middle like I have on my boards and also you cab place the jumper for the negative rail I just did to reinforce the connection for the TO-3
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