right guy to answer that question already posted after you
it demands more gray cells than I have , to complete survey choosing right THD spectra , varying those source resistors
I'm too dumb to do that , except choosing by ear
after that... I think there is not much to do , except scaling OS for more power (and optimizing each actual circuit)........ which I already naively commented many moons ago
my, he's changed a lot. Must be the F6 has taken it's toll
even name
isn't big
but face is more
less
There is a clue about THD in post #374 http://www.diyaudio.com/forums/pass-labs/216616-f6-amplifier-38.html#post3106471.
right guy to answer that question already posted after you
it demands more gray cells than I have , to complete survey choosing right THD spectra , varying those source resistors
I'm too dumb to do that , except choosing by ear
after that... I think there is not much to do , except scaling OS for more power (and optimizing each actual circuit)........ which I already naively commented many moons ago
he's teasing ya
his 0.1 was at 10W , in prototype
OK,maybe later he increase that , deliberately
So my brother, who is wakoo old school, with his phono and tubes, came over to have a listen. I was asking him to evaluate my triode/pentode switch and whether i was correct or just guilty of sniffing too much Elmers glue as a child. Heis type who thinks anything other than tubes is waist of musical energy. He "likes that distortion" His tube amp pentode/triode switch presents wide L to R soundstage in pentode and tall/more vertical soundstage in triode., with better front to back seperation. After listwning to several songs, he begrudgingly admitted to hearing the difference and with great disgust admitted that he liked this amp. THis means nothing to most, but is important to me for two reasons. First, I am not hearing things ans the F6 presents us with a very easy amp to tweak for a particular sound. I am not syaing other amps cannot be done in the same way, i just dont think it is as easy. Secondly, the fact that he admitted to liking the amp says something about its sound, for me. It confirms that either through SS parts, transformer interstage, or just THD fiddling, that misty fets can bring the pain. Just takes time, two functioning ears,willlingess to play,and forum full of help. Measurements help, but should only be used for educational purposes
His tube amp pentode/triode switch presents wide L to R soundstage in pentode and tall/more vertical soundstage in triode., with better front to back seperation. After listwning to several songs, he begrudgingly admitted to hearing the difference and with great disgust admitted that he liked this amp. THis means nothing to most, but is important to me for two reasons. First, I am not hearing things ans the F6 presents us with a very easy amp to tweak for a particular sound. I am not syaing other amps cannot be done in the same way, i just dont think it is as easy. Secondly, the fact that he admitted to liking the amp says something about its sound, for me. It confirms that either through SS parts, transformer interstage, or just THD fiddling, that misty fets can bring the pain. Just takes time, two functioning ears,willlingess to play,and forum full of help. Measurements help, but should only be used for educational purposes
?.... First, I am not hearing things ans the F6 presents us with a very easy amp to tweak for a particular sound. I am not syaing other amps cannot be done in the same way, i just dont think it is as easy....
I'll second you on the fun and easy tweakability of this amp .... If you put the bias and front end on a board, and pp everything else (trafo, rs, feedback resistors, op fets) the easy swticheroos you can pull off are just plain fun to mess with ..... step ups/step down, diff ttransformer types,more/less feedback/gain/h2vsh3 etc tc... Mmmmmmmm
Not a problem. The pot is 20R or more in parallel with the normal source resistor. Look at post #1844 http://www.diyaudio.com/forums/pass-labs/216616-f6-amplifier-185.html#post3164838
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Maybe he just likes the sound of transformers.
Possible isnt it
. If being totally honest, I have to admit there is a certain magic to a nice triode tube, but I am not willing to concede that tubes have the market cornered. This amp, more than any other, has shown me the potential to influence the sound of an amp. It is not with parts but design, something i believe you have tried to show. The RO85 will make its way into this design. HAve you found different sounds in similar topologies between the two SS parts. On paper, they see, to have different responses. I lost interest somewhat in R085 after reading SiT Nemesis article. Shouldnt have given up so easily.He has heard them all. The other amp he likes is BA3 with Ba2 output stage, as do I. I need to figure out if this sound i like is the result of harmonic breakdown, transformer, or even SS fets. Laterals are another transistor that I really like and i enjoyed them in this amp. I am going to post some stupid ideas tomorrow in my new thread. I am really going to play with this thing, as it is so easy to do.
Friend Rene Jaeger has been working on a hybrid topology, with SS PP circuitry using high voltage devices that run at tube voltages. Startlingly sweet sound and with interstage and input transformers to complement the PP OPT, one that was intended for a PP 300 B amp (Lynn Olson's Karna amps had the first pair).
Seems to work well with SS Guitar amps also, a high performance 70 volt line matching transformer works amazingly well, with no other changes.
Bud
I have been tweaking the pots. With Rs=0R20 I found this very interesting pot combo. The pot wipers were quit low, perhaps 0.1 of the hi FET and 0.3 on the low FET. I do not have an accurate way to measure either the pots or the source resistors to say what the exact resistor values might be.
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