Yes, its hard for me to admit that it sounds great as well!
I have learned, from trying, that a good PSU powering the BA-3 is a must. I have tried a quick and dirty Bride of Son Of Zen PSU using +-28Vdc and it is good also but the Sigma 22 is definitely better sounding IME.
My only complaint, if we are splitting hairs, is that it takes minutes to reach the set R11/R12 voltage (about 1 Vdc) and the lowest offset. In short, the preamp needs to warm up a lot before it sounds great!
I have followed instructions from the build guide when I was setting it up. Leave bias to about 900mV for a few weeks usage, then to 1Vdc and minimum offset. To me, there's a profound sound difference between 900 mVdc and close to 1 Vdc in bias. I have not adjusted P3 yet.
Very nice build! Enjoy!
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Hi Amandarae, nice that you got the BA-3 up and running. How do you like the sound, particularly compared to the 26/01a tube pre?
Yes, P3 is supremely important to set the right mix of 2nd and 3rd. I like 2nd higher than 3rd by at least 5-10 db. This has the best blend of sweetness and soundstage in my setup.
The BA-3 is currently in the lead against an all out 801a pre, which is absolutely spectacular by itself.
Yes, P3 is supremely important to set the right mix of 2nd and 3rd. I like 2nd higher than 3rd by at least 5-10 db. This has the best blend of sweetness and soundstage in my setup.
The BA-3 is currently in the lead against an all out 801a pre, which is absolutely spectacular by itself.
Howzit ra7?
I like the sound of the preamp a lot! I do not have the proper equipment to adjust P3, (before soldering, I made sure the resistances are even between the sections) so I cannot try what you suggested.
Yes, it is a contender with the Type 01A and Type 26 preamp. I can see how it can better the tube preamps easily as in my ears, without adjusting P3, the potential is already there.
IME, it is in the ACP+ camp type of sound rather than the BA2018 linestage camp as far as music presentation. But the BA-3, my observation with the supply I am using, has more soundstage and depth than the aformentioned preamps in my opinion. Warm up time is my only complaint. But when it warms up, maybe because my preamp has no case
, it sounds great!In your opinion, can the harmonics be adjusted measuring the difference in resistance between the legs of the pot? Or it is so responsive that the only way to do it is with a display? I meant a small twirl will result to significant amplitude of the wave on display?
Have a great day!
Good to hear that you are liking it too. Warm up is a thing with all Class A, both tubes and solid state. So, I don't mind it at all. As the M2 warms up, you can actually hear it transition from Class B to AB to A. It does take the BA-3 time to warm up.
If you have a multiturn pot on P3, then it won't change by a lot if you turn it once. But the output offset and the bias will vary with changes to P3, so it is best to do it slowly, turning P1 and P2 to compensate somewhat. In my ghetto build, I found that there is more offset at my favored position of P3, which is fine, because a few hundred mV of less swing over 20V is okay for me. It does have a cap on the output for just such a thing.
If you have a soundcard, even the computers own soundcard will do, and REW or ARTA, you can easily set it up for measuring the harmonics.
Soundcard OUT to BA-3
BA-3 out to the IN of the soundcard.
Open up ARTA (free to try, just can't save) in spectrum analyzer mode, select your computer's soundcard under devices, set it up for 1 kHz sine wave and hit record. You are on your way.
As I listen to the BA3, the 801a, and the F4, I'm more and more convinced that getting monotonically reducing harmonic structure, i.e., 2nd higher than 3rd, 3rd higher than fourth, and low to no higher order harmonics, leads to more musical and natural sound. This holds true for tubes and SS. Here's some observations:
Too much 2nd = too sweet with worse soundstage.
3rd higher than 2nd = good soundstage but an edge.
higher orders higher than 2nd or third = unnatural sound.
2nd and 3rd in right amount but accompanied with higher order = glare around instruments.
Only 2nd and 3rd + right amount of each = best sound.
Interestingly, if you have no harmonics at all, such as the output of a good DAC, it can sound boring without being offensive. I'm finding that I actually prefer a bit of 2nd and 3rd added to the sound. Quite odd.
If you have a multiturn pot on P3, then it won't change by a lot if you turn it once. But the output offset and the bias will vary with changes to P3, so it is best to do it slowly, turning P1 and P2 to compensate somewhat. In my ghetto build, I found that there is more offset at my favored position of P3, which is fine, because a few hundred mV of less swing over 20V is okay for me. It does have a cap on the output for just such a thing.
If you have a soundcard, even the computers own soundcard will do, and REW or ARTA, you can easily set it up for measuring the harmonics.
Soundcard OUT to BA-3
BA-3 out to the IN of the soundcard.
Open up ARTA (free to try, just can't save) in spectrum analyzer mode, select your computer's soundcard under devices, set it up for 1 kHz sine wave and hit record. You are on your way.
As I listen to the BA3, the 801a, and the F4, I'm more and more convinced that getting monotonically reducing harmonic structure, i.e., 2nd higher than 3rd, 3rd higher than fourth, and low to no higher order harmonics, leads to more musical and natural sound. This holds true for tubes and SS. Here's some observations:
Too much 2nd = too sweet with worse soundstage.
3rd higher than 2nd = good soundstage but an edge.
higher orders higher than 2nd or third = unnatural sound.
2nd and 3rd in right amount but accompanied with higher order = glare around instruments.
Only 2nd and 3rd + right amount of each = best sound.
Interestingly, if you have no harmonics at all, such as the output of a good DAC, it can sound boring without being offensive. I'm finding that I actually prefer a bit of 2nd and 3rd added to the sound. Quite odd.
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Focusrite 2i2 is what a lot of us use.
Have a look at this thread:
Howto - Distortion Measurements with REW
Regards, Claas
Have a look at this thread:
Howto - Distortion Measurements with REW
Regards, Claas
Focusrite 2i2 is what a lot of us use.
Have a look at this thread:
Howto - Distortion Measurements with REW
Regards, Claas
Thank you Claas! I will read the discussion.
Yes, the Focusrite 2i2 is a solid option. Behringer and others make similar products too:
Access to this page has been denied.
I had the $19 Behringer UCA one many years ago. It still works and is a good cheap option.
But you could also just use your computer's own soundcard. Do a loopback measurement to see where the noise floor is. If you get below -110db or so, you might just be able to use that to set the BA-3 harmonics.
Here's a handy guide:
A DIY approach to distortion measurements for audio amplifiers – (mis) Adventures in Hi-Fi
Access to this page has been denied.
I had the $19 Behringer UCA one many years ago. It still works and is a good cheap option.
But you could also just use your computer's own soundcard. Do a loopback measurement to see where the noise floor is. If you get below -110db or so, you might just be able to use that to set the BA-3 harmonics.
Here's a handy guide:
A DIY approach to distortion measurements for audio amplifiers – (mis) Adventures in Hi-Fi
This may also be of help:
Practical Test & Measurement: Sound Cards for Data Acquisition in Audio Measurements | audioXpress
It has several parts but explains everything.
Practical Test & Measurement: Sound Cards for Data Acquisition in Audio Measurements | audioXpress
It has several parts but explains everything.
greetings, all. i've been happily listening to my BA-3 preamp for a couple years now.... but i'm starting to get that DIY itch to tweak and experiment. i'm going to start stuffing a PSU board to make it dual mono soon... but the first thing i want to do is experiment with some different caps in the C3 position. rather than having to de-solder and solder every time, i'm thinking of just running some wires out to a breadboard to make swapping caps easy. once i settle on the ones i like enough to listen to for a while, i'll commit and solder them in to the pcb. any reason why that approach wouldn't work or be a good idea? are there better solutions for testing and swapping caps without soldering? thanks!
Wouldn‘t the long wires be a problem at this position? I believe C3 to be one of the more important parts, so I‘d rather search for a connector of sorts to be placed onto the pcb itself…
(a „chip-connector“, board-connector, or a screw-on wiring-bridge, anything like that—apologies for failing to provide the correct terms…)
(a „chip-connector“, board-connector, or a screw-on wiring-bridge, anything like that—apologies for failing to provide the correct terms…)
@myleftyear: yes, i guess that's my question. is running the signal out of the chassis to a breadboard and then back a bad idea, even if for the temporary purpose of comparing caps? i had also considered a board connector, but was having trouble finding a single position euroblock type connector that would fit the pcb. maybe i could use a three position one and just break off all except one of the pins?
No, it is not a problem at all to run short clips to caps off the board. I did it and am still doing it to test caps and can easily hear differences. I use alligator clips between R12 leg and the out pad wire to connect to the cap. Be sure to connect the leg of R12 that is closer to the pots. Have fun!
If you look around many folks build entire test circuits using alligator clips. As long as the connection is solid and the wire is thick enough to carry the current, it is all good.
If you look around many folks build entire test circuits using alligator clips. As long as the connection is solid and the wire is thick enough to carry the current, it is all good.
This is good to know.
Adjusting my guidelines…
Flying by the seat of our pants is what we diyers do.
Though one must take proper precautions when experimenting and prototyping.
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Check out Wago connectors on amazon for solderless connections. Very easy to swap things in and out quickly.