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The newer regulated bias supply seems to be much more sensitive to adjustment on my set up and the has about 30-40 % more output than the original bias supply output. I was able to turn up the old bias supply almost 100% on the new BF panels, but the new bias supply operates at 1/3 open on my panels to generate diaphragm discharge.
Thanks for your reply Kikil. While I acknowledge we all different room acoustics, I was interested who else landed on the those settings.
K
Yes, it is smoother and sounds more extended and airy. Measure your 2:00 setting impedance and select the closest resistor to that value. I found that the replacement had even more extension, so I suggest you consider perhaps a slightly higher round up value revisit or to your measured impedance.
I used 2 way tape and hot glue to set the resistor on top of the existing pot and simply resoldered the leads. Easy to change out if you change your mind.
It is worth the effort to give it a go.
Ken
Hello:
I simply measured the resistance across the pot where I normally position the tweeter pot. It has been roughly in the same position over the years. So, I bypassed the tweeter pot with a 4 ohm metal cased fixed resistor, 50 watt, non-inductive. It opened up the top end and to my ears sounds just sounds better. A very nice upgrade. Easy to remove, but why would I…!
Ken
Chungjh:
I get some sibilance on some female recordings(Joni). I have a fixed tweeter level of 4 ohms, equivalent to around 1:00 on the tweeter pot. I can mitigate sibilance with some slight re-toeing of my panels. Mine already have about a 20 degree toe in for a small room. In this scenario, toeing in a bit more, <1/8” actually cuts it down a notch. Depending on your toe in and room size, it may go the other way. Give it a go and report back…
Ken
Hello:
I have a updated Pristine 2. I see you have done a few mods to the frame. What did you do (materials) and how did you fasten the rear brace and front reinforcements? Most importantly, what affect did you hear with the frame mods. I would most interested in your comments.
Ken
Hello again:
I am not aware of anything you could do on the uncovered panel.
Could check if there is a copper diffusion ring on your set. I believe this a factory install. But, you should confirm whether you have it or not.
I would remove all the stables before replacement fabric
Of the fabric, to avoid tears when stretching it in place.Ken
The test looks ok. Your call on inserting the resistor load. Again, my experience is that a new fixed resistor will sound more extended, and cleaner, than the pot, so you may not need to lower the R value down to less than 2 ohms to get your preferred HF extension. Not sure I would…
Chungjh has a good point. You should be measuring across the variable pot. My reaction is that 1.6 ohms seems low. If that’s the correct measured value, I would only say that a fixed resistor will sound cleaner and more open that the measured equivalent on the variable pot. For a small cost, I might suggest you buy a few values, 4 and 3 ohms( 50 watt, non conductive) and the 4 ohm a try. If you want more treble, then consider to go down to a 3 ohm and solder that value in place.
Good luck, I do look forward to your
Feedback on the treble sound change.Ken
Yes. The series of upgrades over the years was not that expensive. The new base focused panels were very cost effective vs purchasing new speakers. Although I do not have the consummate backplates, I have many of the updates in them and to my mind, saved thousands to get a big upgrade with the a unique new “560” base focused panel in a pristine panel metal stand.
Yes, I would like to have 6 or 7’ panel, but in a smaller condo dedicated audio room, they work great.
Running them with a heavily upgraded and modified VTL 225t mono blocks and they have plenty of drive for these panels.
Ken
Stphotog:
If you look at my photo, I am using what I think is your first photo. Frankly, there will be lots of options at parts connextion. I just unwired out the variable pot and hot glued on the new resistor on top of it and solder it in. Simple. Bang, open up the top end. After some time now, I have no motivation to change the 4 ohm value.
Ken
Hello jay:
Yes, I had an older model on the Pristine 2. I think I purchased them back in the mid 1990s.
Since then, diaphragm change, copper diffusion ring, power supply, back plate upgrades, new Reg. bias supplies and a special order design modified 560 base focused panels fitted to the pristine 2 metal frame. Roger says there is nothing more I can do with these backplates.
Ken
Hi Phish10:
The new regulated bias supplies are straight forward to install if you can do easy soldering.
On my backplates, the new bias supplies would not fit horizontally. So, I had to stand them on endwith removal of one plastic flange and secure them with hinge angles and glue.
If you have a larger backplate, they should fit in. Either way, they will fit in.
Roger will send you the bias supplies with sufficient lead length and a new bias pot and schematic for installation. All is straight forward and takes under an hour to fiddle through for each panel. The price from SL is most reasonable in MHO.
Highly recommended to do this. My opinion is that new bias supplies provide almost twice as much bias output as the older unit and is ac input voltage regulated to boot.
Ken
Hi:
No, I did not upgrade the caps.
On the toroid1, I did a series of updates close to the time, so I can’t really comment on the sound upgrade with the Toroid 1. I had experienced progressive improvements in bass extension, image depth and treble extension with all the updates. I am certain this update contributed to the performance enhancement.
If you have not replaced the tweeter pot with a fixed resistor(ie. 4 ohm, 50 watt, non inductive), do it. Best bang for the I buck.
A new regulated bias supply also made a difference, for some reason. It has greater output, and is ac voltage fluctuation independent. But, to my mind, it was an upgrade in overall sound performance. More of everything, so to speak.
I would appreciate so details from you on the what the new caps upgrade are and where you soldered the in. What improvement did you hear with this change?
Ken
Hello:
I sent the backplates to the factory for a Toroid 1 transformer installation. The new Toroid 2 will not fit in your backplate enclosure. Roger may still have the Toroid 1 in stock.
Even with the Toroid 1 installed in the backplate, it would fit in the enclosure. I installed a 1/2” wooden square( 4 separate pieces, each one drilled to arrange with the housing mounting screws. This effectively raises the backplate to accommodate the deeper depth with the Toroid 1 transformer.
Roger also did a minor parts upgrade to the crossover at a small cost while in there.
I attached 2 pics on my backplates with the Toroid 1 and The new regulated bias supply I installed recently. You can see the height difference with the toroid 1 installed.
With the new bias supply, you have to hack saw off one of the flanges(easy) and mount it on its side to fit in the small pristine backplate/ enclosure. I used a small cabinet bracket, screwed to the panel, 2 way tape and hot glue to mount it all together. This is only way it fits in.
Good luck with your project!
Ken
