ok, did some more reading. I'm planning on using 2x200R feedback resistors, and hope to get 6dB more gain, or around a total voltage gain of 10. I'll be using +-24V rails. I have V-grade JFETs. I'm wondering if I should lower the 10 ohm resistors to say 5 ohm, which would keep the same ratio as the original circuit? I suppose this is my single outstanding question. I'm going to leave the 600 ohm resistors the same, as I'm using Fairchild output devices.
You shouldn't have to modify anything - just use the 200 ohm resistors.
6 dB more gain, 6 dB less feedback. What's not to like?
I have some issues with my F5 build... Bought the P-F5-2V20 boards and built w/o the current limiting. I had to remove R3/R4 to get the bias over about 25mA, I wonder if I got fake jfets on epay :-( Biases up just fine with R3/R4 removed, but it's actually a lot more temperature stable w/o the thermistors in the circuit...
I've also got a PS buzz I'm still working on tracking down. It's not lack of filtering, even with 60mH chokes in the PS the buzz is still there, suspect it's RF modulation that I need to knock down.... Need to get this finished up, it's Dad's surprise Christmas present...
Roscoe
I've also got a PS buzz I'm still working on tracking down. It's not lack of filtering, even with 60mH chokes in the PS the buzz is still there, suspect it's RF modulation that I need to knock down.... Need to get this finished up, it's Dad's surprise Christmas present...
Roscoe
I have a question regarding the value of R35 on the cviller v2.0 printed board layout.
The Bill of material indicates R35 to be a 33k value.
But assuming that:
-the LED has a Vf around 1.8V
-the If is around 20mA,
-and the P.S. voltage is around 18V,
it seems to me that the value of the resistor in serie with the LED should be around:
(18-1.8)/0.02=810 ohm
Am I wrong ?
Thanks for your help...
The Bill of material indicates R35 to be a 33k value.
But assuming that:
-the LED has a Vf around 1.8V
-the If is around 20mA,
-and the P.S. voltage is around 18V,
it seems to me that the value of the resistor in serie with the LED should be around:
(18-1.8)/0.02=810 ohm
Am I wrong ?
Thanks for your help...
Turbo F5 and an F6....and a partridge in a pear tree?
Mentor Pass....
Sire,
You had recently given us an update on your Turbo F5.
A while back, you had mentioned/alluded to/teased us, about an F6 design.
Are these two separate and distinct new DIY amps? Or perhaps they are one and the same, now?
Have not heard much recently about the F6. Can you tease us, with a little more detail?? (After all, it is the holiday season, and time to give thanks and offer gifts!)
Merci--and the best of the holiday season, to you, and yours--and all the Class A DIYers out there!
Mentor Pass....
Sire,
You had recently given us an update on your Turbo F5.
A while back, you had mentioned/alluded to/teased us, about an F6 design.
Are these two separate and distinct new DIY amps? Or perhaps they are one and the same, now?
Have not heard much recently about the F6. Can you tease us, with a little more detail?? (After all, it is the holiday season, and time to give thanks and offer gifts!)
Merci--and the best of the holiday season, to you, and yours--and all the Class A DIYers out there!
With that hat, Papa almost looks like he is doing a Tommy Cooper impression
Tommy Cooper: The dancing spoon trick - YouTube
Tommy Cooper: The dancing spoon trick - YouTube
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These are two separate designs. The F6 design is complete, and I simply
need to stuff the pc boards that I designed so that you can see spiffy
finished product, and then I need to write the article.
The F5 is being revised to hold the smoke in better, and will follow very
shortly after.
The F5 is being revised to hold the smoke in better, and will follow very
shortly after.
Maybe you can sell an F5 to the lady downstairs. She's a chain-smoker and it's killing me.
Ahem...... If you need someone to stuff those boards for you (and simultaneously confirm that the boards are "idiot proof"...) then I'd be glad to assist.....
I recall an old Western, as a child..... "Have [soldering] gun, will travel"......
isn't Santa Papa making entire year - one big XMass ?
ya Greedy Boyz ................
Oh, Master of the Zen.....
I'm not Greedy...... I'm NEEDY...... I need to have the aroma of solder flux tickling my nose once again...... I haven't built anything in a month....!
Makes me wonder--do they make an "Essence of solder" cologne??? (After all, Christmas is coming......)
Best of the season, to all....!
Well I don't think it's a PS issue at this point... Pulled one of the input cables out accidentally when I was troubleshooting, and the noise vanished... So, with either channel connected and the other disconnected, quiet as a church mouse, both channels connected, the buzz is back. It's not much, but enough to be noticeable with my 105dB/w horns. I don't think it can be a ground loop, even does it when connected to a battery powered JBOZ that's not connected to anything that's grounded...
Any ideas?
Roscoe
