Hello all,
After many hours -- and a few glasses of whiskey ;-) -- reading through this and other threads on the forum, I'm beginning to gather parts to make the BA-3 preamp to go with my ACA 1.0 (and then eventually the Aleph J, etc.). I'm going for the most straightforward build I can, as I am a complete and utter newbie when it comes to electronics (allow me to underscore the complete and utter newbie part of that last sentence!). As such, I have a few basic questions:
1. Since the Galaxy 388 that 6L6 used in the build guide (which is awesome, btw!) is no longer available, will the Galaxy 2U with dimensions 330mm X 280mm work for this project? I've tried mapping out the PCUs and transformer, and I think it will work, but would appreciate some verification before I order the chassis.
2. What specific kind(s) and gauge(s) of wiring do you all recommend for this project?
3. Less a question and more a statement: For power supply, I think I've decided to go with the AMB Sigma 22 set up for 24v output since there's lots of documentation on the AMB website to hold my hand as I go (and I want to go ahead and get some practice building a PSU in advance of the Aleph J build ;-). That being said, I'm open to other suggestions on the power supply front.
I think that's all for now. More questions will surely follow as I get started. Thanks to 6L6 for the great build guide and everyone else for the helpful posts and inspiring reports about your respective builds!
Scott
After many hours -- and a few glasses of whiskey ;-) -- reading through this and other threads on the forum, I'm beginning to gather parts to make the BA-3 preamp to go with my ACA 1.0 (and then eventually the Aleph J, etc.). I'm going for the most straightforward build I can, as I am a complete and utter newbie when it comes to electronics (allow me to underscore the complete and utter newbie part of that last sentence!). As such, I have a few basic questions:
1. Since the Galaxy 388 that 6L6 used in the build guide (which is awesome, btw!) is no longer available, will the Galaxy 2U with dimensions 330mm X 280mm work for this project? I've tried mapping out the PCUs and transformer, and I think it will work, but would appreciate some verification before I order the chassis.
2. What specific kind(s) and gauge(s) of wiring do you all recommend for this project?
3. Less a question and more a statement: For power supply, I think I've decided to go with the AMB Sigma 22 set up for 24v output since there's lots of documentation on the AMB website to hold my hand as I go (and I want to go ahead and get some practice building a PSU in advance of the Aleph J build ;-). That being said, I'm open to other suggestions on the power supply front.
I think that's all for now. More questions will surely follow as I get started. Thanks to 6L6 for the great build guide and everyone else for the helpful posts and inspiring reports about your respective builds!
Scott
1) Yes. That's tons of room.
2)Whatever you can get your hands on. This is nice - Remington Industries 22UL1007SLDKIT UL1007 22 AWG Gauge Solid Hook-Up Wire Kit, 300V, 0.0253" Diameter, 25' Length: Amazon.com: Industrial & Scientific
3) the Sigma22 is really, really cool. The documentation is also top notch, Ti does a fantastic job. You asked for suggestions, this is a wonderful performer - Dual/Bipolar LV-Reg
2)Whatever you can get your hands on. This is nice - Remington Industries 22UL1007SLDKIT UL1007 22 AWG Gauge Solid Hook-Up Wire Kit, 300V, 0.0253" Diameter, 25' Length: Amazon.com: Industrial & Scientific
3) the Sigma22 is really, really cool. The documentation is also top notch, Ti does a fantastic job. You asked for suggestions, this is a wonderful performer - Dual/Bipolar LV-Reg
I can vouch for the AMB Sigma22 dual regulated PSU, have built 2 of them into 2 previous pre amps (The Kaneda Line stage and the BA3), and now I am building a third one to use with Wayne's BAF 2018 line stage. Very happy with the performance of all.
Thanks for the quick replies, sizing verification, vouching and recommendations, 6L6 and Gary! I had been looking at the GlassWare PSU kits, since that's what you used in the build guide, but wasn't positive the ones they currently offer would work with the BA3. Good to know, and to have a couple options.
Is there a sweet spot when it comes to heatsink height for the PSU? Looks like 1.5-2.5 inches is the general range that would work in the Galaxy 2U.
Is there a sweet spot when it comes to heatsink height for the PSU? Looks like 1.5-2.5 inches is the general range that would work in the Galaxy 2U.
It may be even lower as at that time after P3 adjustment I did not not re-adjust offset. I later found out that I had 1-2 V offset after P3 adjust. Then I re-adjusted to zero offset but did not make a new distortion measurement. The logic says that distortion should be lower…...but who knows 🙂
Think the correct distortion images are a few posts further from #1351....for L and R channel.
The amp plays very nice music.
Yesterday I made a small "operation" on my BA-3 pre. I exchanged the 51k AMRG with 10k Z-Foil serie resistors in the shunt attenuator to have more output (use MoFo as power amp). When I ordered the shunt attenuator I was not "thinking" as the 51k makes a voltage divider with the Rin (47k) of MoFo. A normal pot or stepped attenuator would have been a better choice. However with 10k I have plenty of voltage swing from BA-3 pre. The sensitivity of vol. control feels like a normal amp now. It plays fantastic.
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If instead of the 10uF film cap on the BA3 board, one wanted to use a10uF Silmic and bypass, what voltage rating should the Silmic cap be? I assume there is not much voltage, but wondered if higher voltages ( I see them from 16-50 volts ) may be advantageous or no?
I have some of zenmod's recommended poly carbonate bypass caps and thought I would try this in BA3 and possibly outputs of Wayne's 2018 line stage...
Russellc
I have some of zenmod's recommended poly carbonate bypass caps and thought I would try this in BA3 and possibly outputs of Wayne's 2018 line stage...
Russellc
usually rail voltage and some more is enough for cap rating
absolute safety is rail to rail voltage
absolute safety is rail to rail voltage
Is there a scientific disavantage in using higher voltage rating capacitors when space allows? Lets say i require a rating of 10V but i use one rated 50V. Overrating it what would bring on the harm side?
The higher-rated cap is likely to have a lower ESR. That's usually good.
However, in some feedback circuits a higher ESR is needed to maintain stability. (I think this is the main reason Tantalums were recommended for opamps for so long.)
However, in some feedback circuits a higher ESR is needed to maintain stability. (I think this is the main reason Tantalums were recommended for opamps for so long.)
Continuing the cap conversation here. I've read enough to know there are all sorts of opinions about what kind of cap to use for C3. Based on the build guide and prior posts on this thread, the 10uF Audyn Q4 or, for a bit of a splurge, the Cornell Dubilier are at the top of my list. I'm curious about the bypass option and what that does sonically, but think I'd be wise to keep things simple for this first ground-up build... so, is the Cornell Dubilier worth the extra $, and/or is there anything else I should consider for C3?
to spryor #1399
Good morning spryor,
I like the AUDYN Q4 cap. Sonically and in the special case of the BA-3 because of its size. Fits very nicely on the pcb. But I also used MUNDORF SUPREME caps and WIMA MKP4 in my BA-3 FE (I built 4).
Some others prefer the ELNA SILMICS.....
I never used this CornellDubillier cap you've mentioned. But I use the CornellDubillier MICA caps sometimes (I like them).
For me there are audible differences between caps - but very marginal for me.
I hear it much more in a passive crossover of an loudspeaker.
But that is my opinion. The cap discussion is always a neverending one.... 🙄
Greets
Dirk
Good morning spryor,
I like the AUDYN Q4 cap. Sonically and in the special case of the BA-3 because of its size. Fits very nicely on the pcb. But I also used MUNDORF SUPREME caps and WIMA MKP4 in my BA-3 FE (I built 4).
Some others prefer the ELNA SILMICS.....
I never used this CornellDubillier cap you've mentioned. But I use the CornellDubillier MICA caps sometimes (I like them).
For me there are audible differences between caps - but very marginal for me.
I hear it much more in a passive crossover of an loudspeaker.
But that is my opinion. The cap discussion is always a neverending one.... 🙄
Greets
Dirk