Quick question on capacitor voltage...I see this can be built anywhere between 24 and 32 volt rails but the caps in the build sheet are 25v (both on FE and bias boards). If the JFETS are seeing 24 or 32v and they are after the caps, what voltage do the caps see?
I don't know the math, but just assuming that at 24v rails, with 25v caps, the caps must be seeing less than half of their rating otherwise you wouldn't use them.
If I am using 32v rails, I just want to be sure I am buying the right value caps. Thanks!
I don't know the math, but just assuming that at 24v rails, with 25v caps, the caps must be seeing less than half of their rating otherwise you wouldn't use them.
If I am using 32v rails, I just want to be sure I am buying the right value caps. Thanks!
The caps will see full rail voltage, if you have 32v rails use at least 35v caps. 40v if you want to be extra safe.
Good morning from Italí and merry xmas everybody.
Quick (not so quick maybe...) question, I actually listen through my vintage setup, AR SP9 preamp, dual KT88 power amp, JBL L220, sources an unused Michell Girodec, Sony ES505 and LossLess digital through a MacMini -> Beresford Caiman SEG DAC, nothing great but sounds pretty ok.
I am gonna upgrade the power amp to a FW F4, got the case, boards and FETs, next month transformers (gonna be dual mono) and caps, it will be a skilled tech to put it all together and hopefully a step above in listening pleasure which will not make me regret putting tubes away.
After long preamble I would like to add a pre to the F4 and move the Audio Research to a second setup (I will have either the KT88 or an old upgraded Adcom GFA535) to give voice to my old JBL4311b and thought of the BA-3 to match the F4, how difficult is to put it all together and what's the BOM to get an idea of final cost and, last but no least, is it gonna be a better match and/or an improvement off the old SP9?
Grazie
Quick (not so quick maybe...) question, I actually listen through my vintage setup, AR SP9 preamp, dual KT88 power amp, JBL L220, sources an unused Michell Girodec, Sony ES505 and LossLess digital through a MacMini -> Beresford Caiman SEG DAC, nothing great but sounds pretty ok.
I am gonna upgrade the power amp to a FW F4, got the case, boards and FETs, next month transformers (gonna be dual mono) and caps, it will be a skilled tech to put it all together and hopefully a step above in listening pleasure which will not make me regret putting tubes away.
After long preamble I would like to add a pre to the F4 and move the Audio Research to a second setup (I will have either the KT88 or an old upgraded Adcom GFA535) to give voice to my old JBL4311b and thought of the BA-3 to match the F4, how difficult is to put it all together and what's the BOM to get an idea of final cost and, last but no least, is it gonna be a better match and/or an improvement off the old SP9?
Grazie
The BA-3 and the F4 are a lovely match.
As an example; Nelson paired them together. The BA-3 amplifier is essentially an F4 amplifier with a BA-3 front-end. 🙂
I can't comment re: sound quality comparisons.
Happy Holidays!
Edited to add - you can find some example BoMs and a number of other wonderful ideas in the thread linked below. People configure them in a number of ways. The chassis and the PSU (and perhaps potentiometers and input switching) will likely be the most expensive parts and are up to your preferences. So, it could be done relatively inexpensively, or... not... Some people spend more on capacitors than I might for an entire build. 😀
https://www.diyaudio.com/community/threads/the-ba-3-as-preamp-build-guide.258022/
As an example; Nelson paired them together. The BA-3 amplifier is essentially an F4 amplifier with a BA-3 front-end. 🙂
I can't comment re: sound quality comparisons.
Happy Holidays!
Edited to add - you can find some example BoMs and a number of other wonderful ideas in the thread linked below. People configure them in a number of ways. The chassis and the PSU (and perhaps potentiometers and input switching) will likely be the most expensive parts and are up to your preferences. So, it could be done relatively inexpensively, or... not... Some people spend more on capacitors than I might for an entire build. 😀
https://www.diyaudio.com/community/threads/the-ba-3-as-preamp-build-guide.258022/
Just finished up testing new BA-3 front end boards I made. Came out good. Just need to put them in a chassis now.
if they are going to lay horizontally, no fret
if you're going to mount them in any other way, drill hole or two and tie those Biguns with plastic ties to pcb
or glue them with few spoons of nastiest glue you can find
if you're going to mount them in any other way, drill hole or two and tie those Biguns with plastic ties to pcb
or glue them with few spoons of nastiest glue you can find
Why do you belive this are BA3 replicas? It is as far from BA-3 as you can get. Looks like some kind of no brand chinese thing. Quick and dirty layout and markings without any system.
I built one of these a while ago and never got it working right. The first issue I have is too much voltage from my power supply and I am not sure what do with it or manage it. I was aiming for 32v rails, so I started with dual 24v transformer. I am using XRKs Smooth Like Butter power supply, and it was mentioned that the PS accounts for a 3v drop. Additionally, I read about Anteks and voltage sag under load, so I got an Antek dual 28v transformer. Two actually, since the amp is dual mono. Turns out, under load, I am getting 34 - 36v per rail. Unloaded, I get about 36-38v, with one rail even at 40v. The SLB PS does not have much voltage adjustment range, so either I need new transformers or I have to adjust the amp to account for it. Thoughts?
The other issue is a pulsing noise coming from the voltage stage but I will come back to that later.
The other issue is a pulsing noise coming from the voltage stage but I will come back to that later.
Following along with that idea, I found some inexpensive voltage regulators on Amazon, capable of taking 40v in and bringing it down. Would something like this add noise from its operation? One claims to be a 20a constant current voltage regulator for $14.
You need something more like this-
Positive Negative Power Module, LM317/337 Power Module Positive and Negative Power Voltage Stabilizing Module Low Ripple Linear Adjustable, Positive Negative Voltage Module
https://a.co/d/flEamJW
Positive Negative Power Module, LM317/337 Power Module Positive and Negative Power Voltage Stabilizing Module Low Ripple Linear Adjustable, Positive Negative Voltage Module
https://a.co/d/flEamJW
Thx!! I completely skipped over the fact that I would've needed a bipolar regulator lol. I bought two different kinds as they are cheap enough, and I'll try them both in case one sounds or works better than the other. Though as most of them come from China, it'll be about 2 weeks (maybe more) before I see the second pair.
you wrote. that the input impedance of the B3 output stage is about 5 kohms, is it the same or different for 6 pairs?