Here’s a start:
https://www.etsy.com/listing/958609584/first-watt-f4-ba2-ba3-mosfet-kit
Edit:
@rhthatcher here at diyAudio
https://www.etsy.com/listing/958609584/first-watt-f4-ba2-ba3-mosfet-kit
Edit:
@rhthatcher here at diyAudio
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Also, @rhthatcher has the Fairchild FQP3N30 and FQP3P20 you could use in the BA-3 FE as output transistors.
I have everything you need, including front end Jfets and original matched Toshiba front end 313/2013 transistors. But I will need to match the IRFP’s up for you. Give me a week and I’ll should have very good matches for you. Just let me know what you need, if you don’t go for rthatchers offerCan anyone suggest where I could get the F-4/BA-3 Transistor Kit now that its out of stock in the store? Is it worth getting them myself and trying to match them? Something I haven't done before
no single chassis can cope with original heat, except Modushop 5U/500, borderline
so, count on slight decrease in Iq, which exactly isn't too much of a problem
if you have potent preamp, take a look at https://www.diyaudio.com/community/threads/the-marriage.390965/
potent preamp - because buffers are not included in OS
output capability on par with F4, dynamically
though, if you're searching for rave party amplifier (sustained high SPL), old Behemot sized amps are still better ..... raw power from high rails and plenty of outputs
so, count on slight decrease in Iq, which exactly isn't too much of a problem
if you have potent preamp, take a look at https://www.diyaudio.com/community/threads/the-marriage.390965/
potent preamp - because buffers are not included in OS
output capability on par with F4, dynamically
though, if you're searching for rave party amplifier (sustained high SPL), old Behemot sized amps are still better ..... raw power from high rails and plenty of outputs
Hey all! The build is put on hold for a few weeks. After viewing a house only a few weeks ago it would seem we will be moving next weekend! Has to be the fasted move ever!
The new house has a nice big room for my workshop. But the best bit is the underground basement below the garage. It is basically completely underground... I feel it will be a very very nice listening room..
All parts are basically ready for my build. I will be posting every update onto this thread as a reference for other UK DIYers. And to show all the pitfalls etc that I encounter.
I think when I get moved into the new house next weekend I should just worry about getting the workshop up and running. Who needs sofas and beds lol.
The new house has a nice big room for my workshop. But the best bit is the underground basement below the garage. It is basically completely underground... I feel it will be a very very nice listening room
.. All parts are basically ready for my build. I will be posting every update onto this thread as a reference for other UK DIYers. And to show all the pitfalls etc that I encounter.
I think when I get moved into the new house next weekend I should just worry about getting the workshop up and running. Who needs sofas and beds lol.
Sorry - hijacking the thread...
Good stuff with the ACA mini LifePO4 power @ggetzoff
So I've been holding onto USSA boards for some time and have the parts to do a USSA 5.0... but I want more flexibility than 25w class A output, so was planning on doing the turbo version with 36v rails (class A/B, with some 30watts in class A). Then I got reading about the F4 (yummy parallel mono config), and then the BA-3 (output stage is essentially an F4) but you can daisy chain an additional PCB for a crazy 12 output pair.
I'm not looking for higher dB, but an amplifier with enough grunt to drive multi-way speakers to normal listening volumes (I've have SIT3/F7 before, lacking drive for my tastes).
Many people have stated that BA-3 is better than F4 (6L6 included), but you seem to have a preference for DAC driving an F4 direct... the BA gain stage is not as good as DAC direct?
Do you have any comparative feedback, and is ACA + lifePO4 your current summit?
Good stuff with the ACA mini LifePO4 power @ggetzoff
So I've been holding onto USSA boards for some time and have the parts to do a USSA 5.0... but I want more flexibility than 25w class A output, so was planning on doing the turbo version with 36v rails (class A/B, with some 30watts in class A). Then I got reading about the F4 (yummy parallel mono config), and then the BA-3 (output stage is essentially an F4) but you can daisy chain an additional PCB for a crazy 12 output pair.
I'm not looking for higher dB, but an amplifier with enough grunt to drive multi-way speakers to normal listening volumes (I've have SIT3/F7 before, lacking drive for my tastes).
Many people have stated that BA-3 is better than F4 (6L6 included), but you seem to have a preference for DAC driving an F4 direct... the BA gain stage is not as good as DAC direct?
Do you have any comparative feedback, and is ACA + lifePO4 your current summit?
PM, the F4 was the first Nelson I built along with a BA3 preamp. Love the sound so much I built another F4 and several different preamps with the necessary voltage swing. Running two F4 amps in bridged mode gives me some of the best sound to my old ears (71).
Once you can settle into your new home and complete the build, I believe you too will enjoy the sound of a Nelson F4!!
Once you can settle into your new home and complete the build, I believe you too will enjoy the sound of a Nelson F4!!
The ACA mini (never heard nor built the ACA) has been in the main rig and yes, it is one of the best setups I have ever heard: it is both sweet and detailed at the same time, I absolutely love it. The F4 is another brilliant option and I love that one as well. But, a follower with no gain is going to sound amazing driven directly by the source. All of Nelson's design's ride the very same range of the spectrum: fine, and immense detail, tonal bloom and sweetness.
What I want are for musical elements in the recording to leave a trace. Many modern amp designs are like fireworks that flash, and boom musical elements, but are gone in a brief moment. I want that big, open display of energy, that descends, leaving traces that slowly fade as they descend.
I am fortunate to have the time an money to build and really listens. I wonder how much listening people actually do, and what I mean is serious, concentrated listing. Nelon's designs are so simple and they leave you wanting for nothing. Of course, you have to fine those designs of his that are to your exact liking.
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For anyone who has built either the F4 or the Elekit TU-8600S 300B integrated amp I want to report amazing results using the 300B amp to drive the F4. Imagine the delicacy of the treble and mid-range of the 300B combined with true low end grunt that the F4's current supplies. I've tried all kinds of preamps with the F4, but none of them sound like this or drive the F4 to full output (except possibly The WHAMMY!).
Nelson's white paper on the F4 said that you could drive the power buffer with a flea watt amp. Well, here you go. I strapped Mills 15 ohm 12 watt non-inductive resistors across the left and right speaker terminals, and set the Elekits taps to 8-16 ohms. I made interconnects with banana plugs on one end and RCA jacks on the other. Then you just feed the signal from the 300B amp into the inputs of the F4. Holy cow!
The chain in this system is Oppo BD-95 feeding its digital output into a Denafrips Aries II DAC. The DAC is connected to the input the Elekit TU-8600S and the 8600-S to the F4. Speakers are Arendal 1723 Towers. I haven't tried it with vinyl yet. Unfortunately the Elekit only has one pair of inputs which means some cable swapping is required to get my tubes4hifi phono pre connected.
Has anyone else tried this?
Best,
John
Nelson's white paper on the F4 said that you could drive the power buffer with a flea watt amp. Well, here you go. I strapped Mills 15 ohm 12 watt non-inductive resistors across the left and right speaker terminals, and set the Elekits taps to 8-16 ohms. I made interconnects with banana plugs on one end and RCA jacks on the other. Then you just feed the signal from the 300B amp into the inputs of the F4. Holy cow!
The chain in this system is Oppo BD-95 feeding its digital output into a Denafrips Aries II DAC. The DAC is connected to the input the Elekit TU-8600S and the 8600-S to the F4. Speakers are Arendal 1723 Towers. I haven't tried it with vinyl yet. Unfortunately the Elekit only has one pair of inputs which means some cable swapping is required to get my tubes4hifi phono pre connected.
Has anyone else tried this?
Best,
John
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It’s perfectly legitimate in all honesty. And you probably have a good amount of voltage swing from the TU-8600S (I think it puts out 9 watts RMS/8 ohms so about 8.48V RMS into 8 ohms.) With the much higher input impedance of the F4, your peak to peak voltage will go up.
You now have a tube hybrid amp, pretty much the best of both worlds if the sonic splendor suits your fancy. I’ve heard similar setups, very pleasing.
So carry on and enjoy! Arendal 1723, towers! Excellently designed speakers with constant directivity paradigm in mind
.Best,
Anand.
Looking at the specs, the pre-out of the CAV is spec'd at 2.5V. I suppose you might be able to run the CAV50 amp into the F4 but the amp already puts out 45w in ultralinear mode and 22w in triode... so, I don't think it needs the help of the F4... who knows? It might be an interesting experiment.