Thanks william2001.
The F5m (no longer) contains degeneration of the input jFETs - in contrast to the circuit of post #70 and the classis F5 in general.
All that remain around the midtpoint of the input stage is the (ground reference?) resistor R5, which I assume is the very source of the bias toward 2nd rather than 3rd hamonic distortion selected by Mr. Pass.
How a single resistor to ground - in an otherwise symmetric circuit - can move the bias in an asymmetric direction (=> equal harmonics) I haven't grasped yet...🙄
The F5m (no longer) contains degeneration of the input jFETs - in contrast to the circuit of post #70 and the classis F5 in general.
All that remain around the midtpoint of the input stage is the (ground reference?) resistor R5, which I assume is the very source of the bias toward 2nd rather than 3rd hamonic distortion selected by Mr. Pass.
How a single resistor to ground - in an otherwise symmetric circuit - can move the bias in an asymmetric direction (=> equal harmonics) I haven't grasped yet...🙄
Thypils - I'm just a dumb repair tech, but it seems pretty obvious that Nelson has this F5m dialed in nice and tight for a very specific behavior (2nd harmonic, negative phase) while achieving it with a super low parts count. I hope to get my hands on it to see how it compares to what I currently employ these days, and my old F5 from yesteryear. That one seemed alright at the time, but I didn't have it in the system very long before I moved on..
@6L6. Thanks for the detailed response.
A few other questions:
A few other questions:
- Since the 4U is not available on the DIY Audio Store site I went to Modushop's site. On their site they have the 4U but then say that the 4U is based upon a chassis for DiyAudio and the link is to the Dissipante 4U (300mm). In comparing the measurements to the 4U offered at the DIY Audio Store they appear to be the same. Are they the same chassis? The DIY store 4U appears to offer a front panel that has additional threads and a pilot hole for an LED. Does their Dissapante offer the same? Sorry if the answer should be obvious.
- I have Remington wire for my DC hookups and have been happy with that. For the AC hookup should this be 18 or 20 AWG? And without looking to start a debate is PTFE stranded the way to go? Remington has stranded PTFE from 16 AWG to 30 AWG with a 600 Volt rating.
I'm not 100% sure, but I suspect it's the same chassis with the same options. Send an email or PM to @Gianluca ( info@modushop.com ) and he'll be able to clarify.
That will work nicely. I like 16 or bigger on AC wiring.
That will work nicely. I like 16 or bigger on AC wiring.
Yes. The BA-3 gain stage is the F5 circuit made for front-end or preamp use.
https://diyaudiostore.com/products/burning-amplifier-gain-stage-for-ba-3
I pulled out the May 2008 issue of audioXpress a few days ago and figure 5: simplified circuit caught my eye... 16 years of F5 variations brought nearly full circle, back to that one simple image. How very fitting.
Nelson, I guess I strayed from the chip amp forum in 2007 and found this place. I don't post often and have struggled to grasp each new concept and circuit but I've enjoyed the adventure more than I can express. To you and the FAB, I can only offer a Thank you and hope that it is received with the full intended weight.
With a quick order from digikey, I'm ready for a second lap. Cheers d
Nelson, I guess I strayed from the chip amp forum in 2007 and found this place. I don't post often and have struggled to grasp each new concept and circuit but I've enjoyed the adventure more than I can express. To you and the FAB, I can only offer a Thank you and hope that it is received with the full intended weight.
With a quick order from digikey, I'm ready for a second lap. Cheers d
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Hi Tom,
Assuming you are talking about this chassis https://diyaudiostore.com/collections/chassis/products/deluxe-4u, yes they are the exact same one. This can be purchased at this link https://modushop.biz/site/index.php?route=product/product&product_id=777
Perfectly possible to make it assymetric, for example in the unequal matching of input devices, or source degen of the output devices (less likely here) 🙂
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I've successfully used the 600V PTFE Remington 18 AWG stranded in my builds. If 6L6 recommends 16 AWG, I defer to him. 🙂
I think 2H chefs kiss is the IRFP140/IRFP9140
https://www.diyaudio.com/community/threads/pass-f5m.406472/page-7#post-7575439
My fault on this one.
The listings in the store for the F5M essentials and completion kit were inadvertently made visible before they were complete. They have now been hidden.
The F5M essential and completion kits will be available for sale in the store at 12PM PST / 3PM EST Monday 4th March (see this time in your city).
Systems to handle registration of interest and distribution of sales in a less stressful and more orderly way are on the roadmap.
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Well, likely count me out then.... business trip....
BTW, is the DIY store gonna carry the Burson V7 opamps?