deltavektor,
Your pics need to be bigger, they don't enlarge at all. Please take close up photos of the PCB so we can see the details of your build.
That being said, have you looked through pages 353-362 of this thread? On those pages, Dennis Hui, IAIMH, ZenMod and I helped loads of fellas troubleshoot their F6 builds. There are details in those pages that may help you. It's a simple circuit but it stumps a lot of newbie builders for some reason!
It appears the schematic you are using is from the 1st page of this thread since you have the DIYAUDIOSTORE boards.
What is the value you used for Z1, Z2?
What is the value you used for R7, R8? If it is 10K, it is best to try 3K ohms instead.
Did you make sure you installed the correct JFETS for Q3, Q4? Q3 must be K170 or equivalent and Q4 must be J74 or equivalent.
Do any of the three pins on the MOSFETS Q1, Q2 have any continuity to ground? (They shouldn't).
Did you re-read the 1st post of this thread as 6L6 has specific details for a successful build.
Best,
Anand.
Your pics need to be bigger, they don't enlarge at all. Please take close up photos of the PCB so we can see the details of your build.
That being said, have you looked through pages 353-362 of this thread? On those pages, Dennis Hui, IAIMH, ZenMod and I helped loads of fellas troubleshoot their F6 builds. There are details in those pages that may help you. It's a simple circuit but it stumps a lot of newbie builders for some reason!
It appears the schematic you are using is from the 1st page of this thread since you have the DIYAUDIOSTORE boards.
What is the value you used for Z1, Z2?
What is the value you used for R7, R8? If it is 10K, it is best to try 3K ohms instead.
Did you make sure you installed the correct JFETS for Q3, Q4? Q3 must be K170 or equivalent and Q4 must be J74 or equivalent.
Do any of the three pins on the MOSFETS Q1, Q2 have any continuity to ground? (They shouldn't).
Did you re-read the 1st post of this thread as 6L6 has specific details for a successful build.
Best,
Anand.
F6-Dumb
Okay people, I have read the hundreds of pages on the F6 and got caught up in the mods to the circuit.
Something TA said stuck with me. He said something like, I really can't tell you what an F6 sounds like, but I'm happy with what I hear and the tweaks he has worked out with Pico and others.
So I was going to make some mods, but at the last moment, I came back to what TA said again. If I want to properly judge the changes to an F6, I should have a baseline. When I ordered the board I got the kit, so here's what I think I'm going to do. I'm going to stick with the stock build except for the bias, I'm going to goahead and make that change with the 3LEDs for 6.3v and keep everything else as is unless there is a specific reason to change something else?
Before I start stuffing today, I will order another set of boards and when they arrive, I shall start modding those via what I have read here. I have enough material here to build two or even three of them and can do direct ABC testing of them.
Wellmaybe not for the Diamond, but most everything else.
It's the only way to know for sure!
Okay people, I have read the hundreds of pages on the F6 and got caught up in the mods to the circuit.
Something TA said stuck with me. He said something like, I really can't tell you what an F6 sounds like, but I'm happy with what I hear and the tweaks he has worked out with Pico and others.
So I was going to make some mods, but at the last moment, I came back to what TA said again. If I want to properly judge the changes to an F6, I should have a baseline. When I ordered the board I got the kit, so here's what I think I'm going to do. I'm going to stick with the stock build except for the bias, I'm going to goahead and make that change with the 3LEDs for 6.3v and keep everything else as is unless there is a specific reason to change something else?
Before I start stuffing today, I will order another set of boards and when they arrive, I shall start modding those via what I have read here. I have enough material here to build two or even three of them and can do direct ABC testing of them.
Wellmaybe not for the Diamond, but most everything else.
It's the only way to know for sure!
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Input and output moslty... That said, other parts need to be changedto make that work, so you are changing a lot more than just a drop in change, though there are some of those as well. In some cases, you would need to change the rail voltages as well.
Specifically, the work of Pico and TA, but I need to review just which things Iwant to try. I would like to try and Austin front and perhaps something I could crank a bit at the output.
Specifically, the work of Pico and TA, but I need to review just which things Iwant to try. I would like to try and Austin front and perhaps something I could crank a bit at the output.
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but it'll always sound better if driven with low Rout, which buffer is giving
not all are having source (and volume level sorted) resulting in Rout of 30-50 Ohms
differences between various buffers ( JFet or Diamond or ....) are more matter of taste ( different THD Spectra) than quality itself, under condition that these other buffers are made equally good as existing JFet buffer
it is not best in the world ***, but it is Swiss Knife of buffers
***even if having nature of two pentodes as parts , it still works and sounds better when having proper filtered and/or regulated rails; but there is simply no space for going wild
not all are having source (and volume level sorted) resulting in Rout of 30-50 Ohms
differences between various buffers ( JFet or Diamond or ....) are more matter of taste ( different THD Spectra) than quality itself, under condition that these other buffers are made equally good as existing JFet buffer
it is not best in the world ***, but it is Swiss Knife of buffers
***even if having nature of two pentodes as parts , it still works and sounds better when having proper filtered and/or regulated rails; but there is simply no space for going wild
yeah strongbow, I did the simple RC 'thing' (not much difference actually) then went a bit over-the-top and used a basic transistor cap multiplier (bc547, etc ) - and that worked well - the IPS7 (from the M2x) is presenting some difficulties but nowhere near trying to fit the Aikido valve stage (Glassware - 8dB gain)!
Good evening / afternoon,
Many thanks to all for the detail (especially 6A6 for this manual)that has helped get my F6 to this point. Having been through loads of posts to find out why my source resistor was reading 0V on both channels, checking and double checking the stuffing I find that you need to wind those trim pots quite a bit!!!
Can I just please ask for a little help. I have checked psu with bulb lead, connected each amp individually and started bias and am now onto setting without bulb lead. I can get the 0.5V on bias but cannot get below 358mV on offset. I have 3K3 for R7 and R8 swap, do I also do both Z1 and Z2 with a 5.6V swap (or just Z1 and Z2)
I know if I read for another couple of hours I'll find the answer but I only have so much patience left and I need that for soldering!
Thanks in advance...
Many thanks to all for the detail (especially 6A6 for this manual)that has helped get my F6 to this point. Having been through loads of posts to find out why my source resistor was reading 0V on both channels, checking and double checking the stuffing I find that you need to wind those trim pots quite a bit!!!
Can I just please ask for a little help. I have checked psu with bulb lead, connected each amp individually and started bias and am now onto setting without bulb lead. I can get the 0.5V on bias but cannot get below 358mV on offset. I have 3K3 for R7 and R8 swap, do I also do both Z1 and Z2 with a 5.6V swap (or just Z1 and Z2)
I know if I read for another couple of hours I'll find the answer but I only have so much patience left and I need that for soldering!
Thanks in advance...
Good evening Anand
I swapped out the 10k resistors for 3.3K and the bais responded a bit better but I need to get to the zeners.
Hi, long time luker, super noobie. took forever but I read all 375 pages of this guide. Felt pretty confident, still managed to hook up one channel backwards and blew most on the components. A brother helped me out and sent me new parts and I got everything biased up beautifully. The real reason I am posting is to let anyone who is wondering know that 25 watts of F6 will drive a KEF LS50 no problem. I used a class D 250 watt solution before and can't believe the volume levels I am able to achieve. You dont need a super efficient horn speaker to enjoy this amp. Currently running with a carver c-1 preamp(modified) and a topping d50. Wow best I have ever heard.