As you have plenty of room on the pcb, why not add some supply rail voltage conditioning like the small 7*12 regs, a simple bc3** cap multiplier filter, etc and then you could 'common up' the rails for single connection.
If you want to be a bit pedantic, there's a version of this type of circuit that adds a resistor between the 2sj74 fet and neg rail to balance the transconductance to the 2sk170 (about 5 ohms, if I remember correctly) - not saying to do this but to make provision for a posible later mod ...
If you want to be a bit pedantic, there's a version of this type of circuit that adds a resistor between the 2sj74 fet and neg rail to balance the transconductance to the 2sk170 (about 5 ohms, if I remember correctly) - not saying to do this but to make provision for a posible later mod ...
Well, at this point, I tried it out and prefer the BA2018 that I have better. I needed the 2sk70/74's for another project so it was no trouble to try it. I like the large soundstage that the BA2018 throws and the imaging. I would be happy to throw something into the design and share it but probably won't have it printed/tested etc.
Draw me up a schematic of what you are thinking.
If you think it will work and it looks simple, I will add it in and you can try it if you like. I have been honing a few functional details out now that I have done a few PCBs.
I still need to do the ouput cap version alterations.
Draw me up a schematic of what you are thinking.
If you think it will work and it looks simple, I will add it in and you can try it if you like. I have been honing a few functional details out now that I have done a few PCBs. I still need to do the ouput cap version alterations.
I found it in some ways didn’t match the WLS. But, after adding a crappy RC network after the reg, and a cap for testing veeery close to the drains, it in my opinion just barely beats the WLS. It sounds more natural and of course gain structure is very much better. Note that I found it to sound better with an output protection resistor than without.
It is not as liquid as the WLS. But it is completely free of coloration, making my question the naturalness of the WLS’es liquidity.
I am still experimenting, and of course results and preferences may vary. But this circuit is very high bandwith and sensitive to power supply inductance. So without an on board RC network, preferably 4 in total, or cap multiplier or whatever, it will sound different than without. It is a circuit I find most tuneable through small changes, pretty entertaining
It is not as liquid as the WLS. But it is completely free of coloration, making my question the naturalness of the WLS’es liquidity.
I am still experimenting, and of course results and preferences may vary. But this circuit is very high bandwith and sensitive to power supply inductance. So without an on board RC network, preferably 4 in total, or cap multiplier or whatever, it will sound different than without. It is a circuit I find most tuneable through small changes, pretty entertaining
Very cool. I tried it without the output protection resistor. Those JFETs are now stuffed into another project. I will have to circle back to this B1R2 once I see what people do with it. I'm too lazy to experiment with it right now 😂
So you're saying RC network, four of them. Are you thinking RCRCRCRC? That's quite a bit of filtering!
So you're saying RC network, four of them. Are you thinking RCRCRCRC? That's quite a bit of filtering!
No, sorry, I was being very unclear. According to both Pico and MZM, one RC bank for each rail of each channel, is beneficial. I currently use half of that, so both chans share one positive RC, and one negative RC. But it sounds pretty decent.
I have postponed further tinkering a bit, i got hold of some old bigass Tannoys, so there is work to be done there too
The sound without caps and preferably also an R before the C close to the circuit, was a thinner almost bassless sound.
I have postponed further tinkering a bit, i got hold of some old bigass Tannoys, so there is work to be done there too
The sound without caps and preferably also an R before the C close to the circuit, was a thinner almost bassless sound.
I got these boards back last week. I saw some one else do something similar and wanted one for myself so laid out my own. I may be able to get them stuffed and tested this weekend. It uses LM317 and LM337 for the regulators and an Alps pot. I'll use a wall wart transformer. There are also jumpers so you can forgo the onboard power supply and populate and use it with an external supply. The pot is sitting on the board to show scale.
If it works Ok, I'd be happy to share the boards, BOM, Gerbers, or KiCad project files.
AudioSteve, that board looks terrific! Nice work!
Ah, I see. That makes more sense. What values are you using for your RC's a the moment? Tannoys! I wonder who inspired that avenue! What model?
I am familiar with amps/preamps responding a lot to power supplies. I have had an amp that I thought sounded marginal compared to others. clean up the PS and all the sudden things are awesome. An amp that had a huge effect with this aspect is a Stasis amp I have.
I will circle back to this B1R2 after I get past a couple of projects that I have sitting on my bench. Thank you for sharing the details on your build so far I tried the B1R2 with the Helios Bipolar power supply same as yours. The voltage adjustment on that power supply is just to convinient.
No, sorry, I was being very unclear. According to both Pico and MZM, one RC bank for each rail of each channel, is beneficial. I currently use half of that, so both chans share one positive RC, and one negative RC. But it sounds pretty decent.
I have postponed further tinkering a bit, i got hold of some old bigass Tannoys, so there is work to be done there too
The sound without caps and preferably also an R before the C close to the circuit, was a thinner almost bassless sound.
Ah, I see. That makes more sense. What values are you using for your RC's a the moment? Tannoys! I wonder who inspired that avenue!
What model?I am familiar with amps/preamps responding a lot to power supplies. I have had an amp that I thought sounded marginal compared to others. clean up the PS and all the sudden things are awesome. An amp that had a huge effect with this aspect is a Stasis amp I have.
I will circle back to this B1R2 after I get past a couple of projects that I have sitting on my bench. Thank you for sharing the details on your build so far
I tried the B1R2 with the Helios Bipolar power supply same as yours. The voltage adjustment on that power supply is just to convinient.
As usual, MZM had nothing to do with it
Still working on driver A. Attached is before and after pic of cone and surround cleanup (yes, hours there…) and two coats of Dammar, awaiting third coat. Then on to removing paint from the basket, sanding and spraypainting to pimp it up.
Tweeter diaphragm will also be replaced, and I also got hold of a second tweeter replacement for driver B from Tannoy’s stock, on it’s way. Nice to have on hand, and more won’t be made.
Drivers are 3134’s from CPA12. I have those boxes too, won’t be used, and crossovers (will be used). Drivers will eventually go into boxes drawn by the great MZM.
These drivers are like an old race car/pr0nstar: you can readily see the former grandeur, but some glossing is needed for further duty ❤️
The CPA’s used to sit in the national theater playing lounge music. But even though initial listening impressions were OK, they clearly need a lot of tlc. Just found out I may need to disassemble cone/driver B, there is scratching. Need to investigate further, but first I wanna finish driver A.
Still working on driver A. Attached is before and after pic of cone and surround cleanup (yes, hours there…) and two coats of Dammar, awaiting third coat. Then on to removing paint from the basket, sanding and spraypainting to pimp it up.
Tweeter diaphragm will also be replaced, and I also got hold of a second tweeter replacement for driver B from Tannoy’s stock, on it’s way. Nice to have on hand, and more won’t be made.
Drivers are 3134’s from CPA12. I have those boxes too, won’t be used, and crossovers (will be used). Drivers will eventually go into boxes drawn by the great MZM.
These drivers are like an old race car/pr0nstar: you can readily see the former grandeur, but some glossing is needed for further duty ❤️
The CPA’s used to sit in the national theater playing lounge music. But even though initial listening impressions were OK, they clearly need a lot of tlc. Just found out I may need to disassemble cone/driver B, there is scratching. Need to investigate further, but first I wanna finish driver A.
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Very cool! The best old pr0nstar's can still make you weak in the knees. Is Dammar what they used at the factory?
I have SLOBs on my list of things to try someday. Tannoys as well. Now I got to look up Mighty's box design!
I am not too familiar with Tannoys design. However, Do the magnets shift on them? What I have done in the past is to gently touch the outer perimeter of the cone in different spots while playing a sine wave that exemplifies the scratch/buzz sound. cautiously of course. When the scratching goes away, the cause is usually on the opposing side of the voice coil. I don't know how easy they are to take apart but they look to be in pretty good shape after your work.
A few things that I have run into that cause noise is, junk in the voice coil gap which can sometimes be cleaned with tape. A loose spider to basket or spider to voice coil joint. bad voice coils which can usually be measured. A magnet doesn't have index pins but rather a failed glue joint. The magnet can be slid back into place while checking the gap, and then epoxied around the parameter. I have done that a couple of times.
However, Tannoys may just be a completely different beast and I may just have no clue what I am talking about.
Driver A ready for basket paint after 3rd coat of dammar. No, they did not dammarize at the factory, that much I know
The outer rim (haha) fell off. But that was so damaged and ugly, I want a new one. Links appreciated.
Reattaching the pic of the same driver upon reception in casa de vikingolo. Pretty pleased so far, thanks to sizzy moi and MZMs tireless motivation.
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funnytalianViking is informed what to do, always for two steps in future
my e-mail inbox is cluttered with e-mails from Norway
whatever reason is for scratchyscratchy, he'll find it soon enough, with some soaking of spider edge
magic word is 3833, in my Blog
and yes, plasticky ring for beautification of basket rim - nothing what sandpaper and some mat-black spray paint can't cure
just imagine how he's going to be happy after finishing everything - finally pair of speakers he actually invested some elbow and brain grease
my e-mail inbox is cluttered with e-mails from Norway
whatever reason is for scratchyscratchy, he'll find it soon enough, with some soaking of spider edge
magic word is 3833, in my Blog
and yes, plasticky ring for beautification of basket rim - nothing what sandpaper and some mat-black spray paint can't cure
just imagine how he's going to be happy after finishing everything - finally pair of speakers he actually invested some elbow and brain grease