What about David Hasselhoff? 😂 Weekend finally here, I need to give my BA3 a tune up. Last time offset was fine. My heat sinks are quite warm, but far from hot. Figuring I might up the bias a touch. Both front end and Output stage.
Russellc
Did some quick mods today to follow up the last changes. R13 @ 230R now, making the circuit closer to stock gain after the R10 and R11 reductions to 12R a few weeks ago (both loads hence reduced but ratio remains almost the same) Also, R12 is now jumpered, and R1 reduced to 500R. First impression is gooood.
Hi everyone! Please help me with dumb question:
I need to know ba-3 front end input impedance.
It's input stage is very similar to F5.
On FW website I found, that F5 input impedance is 100k. Is this value right for the ba-3 front end?
I need to know ba-3 front end input impedance.
It's input stage is very similar to F5.
On FW website I found, that F5 input impedance is 100k. Is this value right for the ba-3 front end?
The BA-3 FE's input impedance is 47k.
If you compare schematics you will see that the F5 has a 100k resistor and the BA-3 FE has a 47k resistor at their inputs.
If you compare schematics you will see that the F5 has a 100k resistor and the BA-3 FE has a 47k resistor at their inputs.
Thnx, Ben Mah! So, i'm a little bit confused. Original F5 schematics has 47k input resistor.
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I see the source of the confusion; that's actually the slightly modified version in the F5 Turbo article.
The schematics as described in the original Audioxpress article can be found in Figure 6 here:
https://www.firstwatt.com/wp-content/uploads/2023/08/prod_f5_man.pdf
The schematics as described in the original Audioxpress article can be found in Figure 6 here:
https://www.firstwatt.com/wp-content/uploads/2023/08/prod_f5_man.pdf
Can we safely modify that resistor?
I know it was ok to do so with the f4. I think I changed that one from 47k to 200k based on a response from Nelson at some point. If it's important to someone I can check the exact value...
Hi. I"m going to build fully balanced preamplifier with two BA-3 PCB and ladder relay attenuator, controlled by Arduino.
PS would be separate for each channel, double mono.
My question is what VA ratio transformer should I take?
I found 250VA 2x18-0-18V 3.5A, and I suppose it is a little oversize for this job.
PS would be separate for each channel, double mono.
My question is what VA ratio transformer should I take?
I found 250VA 2x18-0-18V 3.5A, and I suppose it is a little oversize for this job.
I am curious to learn about your balanced relay attenuator if you are interested in sharing.
An oversized transformer won't hurt anything. I tend to go oversized as I like to swap them into different projects just for the heck of it. For instance, I swapped the transformer for a BA-3 preamp project I did to power a ACA mini recently. I am glad I went oversized on that one as it came in handy.
An oversized transformer won't hurt anything. I tend to go oversized as I like to swap them into different projects just for the heck of it. For instance, I swapped the transformer for a BA-3 preamp project I did to power a ACA mini recently. I am glad I went oversized on that one as it came in handy.
It's just a project right now. Not a real one.
I'm going to use two sets of 8 relays, each with two groups of switching contacts.
Don't know, if I could post some links here or not.
There are some online calculators for resistors values. There are some different schematics for the attenuator: one with constant input impedance and one with constant output impedance.
It would be controlled with Arduino mega, with encoder and 433Mhz remote(not sure, but may be).
I have 24V Finder relays in my junk, so I'm going to use optocouplers to operate them.
If it is interesting for you, I can share the PCB, when it would be ready.
Feel free to ask questions.
I'm going to use two sets of 8 relays, each with two groups of switching contacts.
Don't know, if I could post some links here or not.
There are some online calculators for resistors values. There are some different schematics for the attenuator: one with constant input impedance and one with constant output impedance.
It would be controlled with Arduino mega, with encoder and 433Mhz remote(not sure, but may be).
I have 24V Finder relays in my junk, so I'm going to use optocouplers to operate them.
If it is interesting for you, I can share the PCB, when it would be ready.
Feel free to ask questions.
Sure, it is relevant to your BA-3 project so why not. I think links are perfectly fine.
Yes, I am interested in the PCB. I will shoot you a PM. 🙂
Yes, I am interested in the PCB. I will shoot you a PM. 🙂
Hi guys, I'm looking for a gain of x10, could you link me the final schematic with bill of materials, voltages, bias, manual guide, etc.
TIA
Felipe
TIA
Felipe
^ To the best of my knowledge, there is no one single page that would provide all of this information. Unless someone is willing to assemble that information for you (or someone has already done it and can provide it to you), you'll need to look around a little. The first few posts of this thread provide almost everything you may need. After that, if you have specific questions, please post.
As ItsAllInMyHead just correctly stated (and I had to do the same) one has to pour through the subforum and piecemeal the info yourself but just go to page one of this subforum (https://www.diyaudio.com/community/threads/the-ba-3-as-preamp-build-guide.258022/) ... Everything should be there if all you want is info on constructing the BA-3 as a preamp. 6L6 has done a great job of putting it together
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Volunteers to assemble the discussed? Personally, I'm looking to potentially build it as a pre. However, the whole thread is a bit long in the tooth. I don't have the skill to identify what is good information and what is a good revision, etc. I'm just a cut and paste guy, merely dangerous with a soldering iron - more likely to set my house on fire than anything else.
I can get together the subforum's posting numbers that were good for me but it's easy just to try searching the subforum for specific info you have questions about.
I can certainly try to help, but this is the power amplifier thread. So, it would be good to separate the two into the appropriate chunks.
As an example, building a BA-3 set of boards into a fully functioning pre-amp (with attenuation, input selection, etc. etc.) is slightly different than needing the BA-3 + BA-2 output stage to build a BA-3 power amplifier.
This all can be a bit overwhelming (it sure as heck was for me) as it gets sorted out, but ... I will do my best to help assemble the info.
What I can also do... 🙂 is when / if we get it tackled, I'll post link(s) to that information from the store page to make it easy to find for other would-be BA builders. I know those that follow would be hugely appreciative of any efforts.
As an example, building a BA-3 set of boards into a fully functioning pre-amp (with attenuation, input selection, etc. etc.) is slightly different than needing the BA-3 + BA-2 output stage to build a BA-3 power amplifier.
This all can be a bit overwhelming (it sure as heck was for me) as it gets sorted out, but ... I will do my best to help assemble the info.
What I can also do... 🙂 is when / if we get it tackled, I'll post link(s) to that information from the store page to make it easy to find for other would-be BA builders. I know those that follow would be hugely appreciative of any efforts.