I am listening to a transformer coupled (Lundahl) Type 26 preamp driving an F4 with Macmini as source and Bifrost as DAC and very happy! Yes, maybe not a lot of gain but in my 20' x 22' x ~ 14' cubic feet room, it is more than enough for me (because I have a 98 ~99 dB speakers).
My observation is that I never heard as close to the real sound of the type 26 tube until now. So long type 01A
, until next time.
My observation is that I never heard as close to the real sound of the type 26 tube until now. So long type 01A
, until next time.
I was just looking at the thread "What are the requirements for driving a 300b"
https://www.diyaudio.com/community/threads/what-are-the-requirements-for-driving-a-300b.35271/
Sy says for instance: "Depends on your operating point. You want to be able to swing something more than the standing cathode-to-grid voltage for class A or AB1. You want a source impedance low enough to keep the rolloff from the time constant (pole) formed by the driver source impedance and the input capacitance of the 300B at least a decade higher than the dominant pole. If you're running the 300B in a greater-than-unity-gain output stage, be sure to account for the Miller input capacitance, too."
So I'm asking "What are the requirements for driving an F4" in a similar way. The input impedance is 47K and the output impedance of the 10Y is around 5K so that's possible. So I want to know how much voltage to swing and if the current of 9mA in my circuit is adequate. And whether Miller capacitance pays a role here. Plus any other factors that are relevant.
finally getting around to assembling some F4 monsterblocks. Trying to learn transistors after years of playing with tubes. The F4 MOSFET kit shipped with Harris IRFP9141. Looking for a datasheet but mouser and digikey come up empty on the part number. Anyone able to fill me in on how these differ from an IRFP9140?
80v vs. 100v part. For this application is inconsequential.
😎
https://www.datasheets360.com/part/detail/irfp9141/5074906896301453549/
😎
https://www.datasheets360.com/part/detail/irfp9141/5074906896301453549/
Partially OT, I have a question after long time not lurking the forum.
How you all guys doing, tutti bene?
Well, that's not the question of course, it being the F4 had an issue with fuses blowing, it underwent care of a dear skilled friend who arranged a delayed charge of the caps, sort of soft start and a few more things and now it is back in place coupled with the AudioResearch SP9, without to go through detail and comparison with the amp it replaced and until the BA-3 takes shape (we'll begin to work onto assembly in late Jan probably), I would like to try and figure how the F4 would sound with some more gain and seem to recall that it can be driven by a power amp, what would it happen if between it and the preamp I stack another power amp to boost gain a little just to figure, any danger, any precautions to follow?
Grazie
How you all guys doing, tutti bene?
Well, that's not the question of course, it being the F4 had an issue with fuses blowing, it underwent care of a dear skilled friend who arranged a delayed charge of the caps, sort of soft start and a few more things and now it is back in place coupled with the AudioResearch SP9, without to go through detail and comparison with the amp it replaced and until the BA-3 takes shape (we'll begin to work onto assembly in late Jan probably), I would like to try and figure how the F4 would sound with some more gain and seem to recall that it can be driven by a power amp, what would it happen if between it and the preamp I stack another power amp to boost gain a little just to figure, any danger, any precautions to follow?
Grazie
Ciao Zen, always prompt and helpful, I have no clue what a flea is (sorry, my English falls behind my Italian which is already on its own not that great...) but so far can I drive, say, an old Carver (which has front gain control for each channel) with my AR preamp and then the F4 with the Carver?
Preamp wise I thought the SP9 would make it but it's on the edge, I know I can't compare F4 sound with the old tube one (KT88) but I can tell there is a lack of "drive" especially in the bottom side of the audio range and that's why, while the BA-3 comes to life, I just wish to listen to the F4 with a few more db input to figure if the extra gain would make it.
Grazie sempre ed ancora
if you introduce potent power amp in between, count on risk - someone will turn that volume way more than F4 is capable to give, there is clipping, bye to your speakers
wait for proper preamp
if you can't wait, put F4 aside, connect Carver amp
Flea power means potere delle pulci ....... meaning - low power amp
wait for proper preamp
if you can't wait, put F4 aside, connect Carver amp
Flea power means potere delle pulci ....... meaning - low power amp
Ok, I will either leave things as they are until the BA-3 sees life or swap back with the KT88 in the meantime to have the extra punch in the low dept, the Carver is just sitting in a drawer (along with a pre and power amp from Adcom I have recently had upgraded which are gonna go for sale or as a present to some new owner) and thought of it to feed 4-6 extra db to the F4, I lost track of the whole BA-3 thread but I think it has quite a lot more gain than my SP9, it will be dual mono design with around 30V to drive the BA-3 board so it should be plenty of gain to properly feed the F4 and my ancient 90dbW/m speakers
Di nuovo grazie
Finally have one of the F6 monsterblocks switched over to F4 boards.
Had it up and running for an hour, watching the voltmeter, checking temperatures. Wasn't getting above room temperature. another hour later, I realized that 0.013 volts is about an order of magnitude too low to get any serious current flowing. doh.
Had it up and running for an hour, watching the voltmeter, checking temperatures. Wasn't getting above room temperature. another hour later, I realized that 0.013 volts is about an order of magnitude too low to get any serious current flowing. doh.
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We just got done listening to Neil Young's Cortez The Killer, Master on Tidal... CJ PV9 with teflon caps, Android, Burson Swing DAC, Elac Unifi B52. I'm giving you the rest of the equipment for this setup because....
...this amp is ABSOLUTELY the best I've ever heard (or rather NOT heard). Neil's voice was there... the drum kit there, the guitar right there... my preamp is really good and this thing just gets out of the way and displays it.
The presentation of the music (this is a very good recording) is honest, nothing etched, nothing exaggerated, bass a little shy (speakers...), but the speed, the microdynamics, extended treble, palpable images of the instruments, voices, layering, etc... all laid bare.
MInd you, the other option in my main 2 channel set up is the A2s driving Maggie 1.7s.. .and THAT is extremely good, mind you...
The problem, currently in my setup, is in the macrodynamics... there just isn't enough power to drive the speakers... and no way will it drive the Maggies.
But...
I can only think of two upgrades:
(1) because the little Elacs need more power, so I bought a used pair of Audio Note AN-L LX speakers, should be here next Tuesday. At 90db, vs 85, efficiency, that ought to help the dynamics.
(2) A preamp/transformer front end that can drive 28V and a pair of gargantuan F4 Turbo V4s that can drive 7A each.. .that should offer the 200wpc that are mandatory when driving a Maggie 1.7 -and below.
Honestly, the day Nelson Pass designs the F4 Turbo V4 he might as well retire from amps and endeavor himself to preamps, transformers and high efficiency speakers!
Everything else will satisfy our wants, nor our needs.
This thing is that good.
...this amp is ABSOLUTELY the best I've ever heard (or rather NOT heard). Neil's voice was there... the drum kit there, the guitar right there... my preamp is really good and this thing just gets out of the way and displays it.
The presentation of the music (this is a very good recording) is honest, nothing etched, nothing exaggerated, bass a little shy (speakers...), but the speed, the microdynamics, extended treble, palpable images of the instruments, voices, layering, etc... all laid bare.
MInd you, the other option in my main 2 channel set up is the A2s driving Maggie 1.7s.. .and THAT is extremely good, mind you...
The problem, currently in my setup, is in the macrodynamics... there just isn't enough power to drive the speakers... and no way will it drive the Maggies.
But...
I can only think of two upgrades:
(1) because the little Elacs need more power, so I bought a used pair of Audio Note AN-L LX speakers, should be here next Tuesday. At 90db, vs 85, efficiency, that ought to help the dynamics.
(2) A preamp/transformer front end that can drive 28V and a pair of gargantuan F4 Turbo V4s that can drive 7A each.. .that should offer the 200wpc that are mandatory when driving a Maggie 1.7 -and below.
Honestly, the day Nelson Pass designs the F4 Turbo V4 he might as well retire from amps and endeavor himself to preamps, transformers and high efficiency speakers!
Everything else will satisfy our wants, nor our needs.
This thing is that good.