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Thank you for the pictures of your Majestic 745s. I will say that schematically they are the same. You have 3 capacitors in parallel that form a 24uf capacitor. I have a single (the silver colored cylinder) a 36uf PIO capacitor. You have non-inductive wire-wound heat sinked resistors (8 ohms likely). I have non-inductive wire-wound resistors on ceramic that are 12 ohms. It appears we both have the Toroid ll. My Toroid ll will be operating over a wider bandwidth because of the capacitance and resistive differences.
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Here is more explanation from a previous question. I will say the Toroid ll was an upgrade that you can definitely hear a great improvement in sound quality right off the bat. Ask others who have the Toroid ll interfaces or have upgraded.
I did all the work in conjunction with discussions with Dr. West. He is a great person and willing to talk to anyone with an interest in speakers (even if you want to modify or upgrade them). Most of what I did was just part replacement to better components. The better components were bigger so they had to be housed outside the interface. I put what components I could on the original interface so it fit within my A1 oak cabinet. The other components were housed in the computer box in the picture (I would change this if you want it to look good). The computer box can be placed anywhere but I put it right behind the speaker. Note that the computer box has three connection points. The single connection point hooks to the single connection point on the interface. The two connection points on the computer box hook to the power amplifier connection points on the interface (Red on the computer box goes to + on the interface and Black on the computer box goes to – on the interface) You can use plain wire, spades, or banana plugs for the connections. You connect your amplifier to the interface in the normal way.
The only major change other than component upgrades (and figuring out how to put this all together (I’m an electrical engineer) was changing where the crossover point (e.g. where the Toroid ll takes over from the Square transformer). The upgrades were inductors, resistors, and paper in oil capacitor. Using the Toroid ll with an older interface provides benefits but really does not take advantage of the higher saturation capability of the Toroid ll). The best benefit is allowing the Toroid ll to manage a wider bandwidth. I believe a standard Toroid l interface operates at 550Hz and above. Dr. West said that the Toroid ll can operate to about 250Hz. What I will say is that you can hear the benefits of the Toroid ll just by popping it in.
Under Dr. West’s advise, I used the 36uf capacitor with 12 ohms of resistance to increase the bandwith of operation of the Toroid ll to maximize it’s capability. That is the large capacitor in the computer box and the two non-inductive wire wound resistors in the computer box. I believe the standard interface uses a 24uf capacitor and 8 or 12 ohms of resistance with the Toroid l. They are overkill but are all high voltage devices.
The only other modification was taking out the brilliance control. This is just a cheap potentiometer (variable resistor) that everyone seems to complain about. I believe it is 8 ohms. I measured my setting which was 5 ohms and used 5 discrete 50 Watt metal film resistors. Although they didn’t need it, I attached them to the heat sink in the computer box. I know others have bypassed this completely (e.g. shorted it out). You could easily short a resistor out (they are under the heat sink) with a piece of wire or add resistors to change the tone (if you know how to solder).
As stated, there are no changes to the schematic of the interface just parts upgrades and a change in the frequency of operation.
I hope this helps. Let me know if you have other questions.
Thanks
Gary -
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Hi Gary
I have read of others doing backplate upgrades along these lines, but you seem to have taken it to a wonderful level ! I have a pair of M1’s (upgraded with DIY Ultimate type steel frames), and a wonderful pair of Majestics 945’s. I have long wanted to upgrade the 945’s to the Toroid II, and if possible, improved electronics. I had planned to eventually sell the M1’s to finance my potential upgrades. My timing might be off. Do these have Roger’s latest Universal Power Supply module ? A while back, Roger sold me two sets of these to upgrade both of mine (I am in Australia, 240v). But if yours aren’t, I could swap two over. Could you send me any other photos or details that you might have. My email is peter.ferguson2021@gmail.com
Regards, Peter -
Someone asked the question why are the electronics in the box needed? Here was my response:
The parts in the box are replacement for the cheaper components used in a standard interface. The original components fit on a little PC board. As you can see the parts I have replaced them with are much larger than what was in the original interface. They obviously do not fit on the plate and were also very expensive.
Original Interface has Sandcast resistors
– I used non-inductive wire wound high power resistors on ceramic (These are green colored)Original Interface has 24uf Capacitor
– I used a PIO (Paper in Oil) 36uf 300V capacitor (This is silver colored)Original Interface has Brillance Control Potentiometer
– I used 5 1 ohm discrete 50W metal film resistors in series (e.g. 5 ohms). Which was a little past center on the Brillance Control -
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I will be moving soon and have to sell my Soundlab A1’s. I was going to sell them local but I doubt anyone near me would appreciate the work I put into the interfaces so I thought I would try here first. I will sell the pair of interfaces for 5K + shipping. I built these with input from Dr. West and we lowered the “crossover” frequency to about 300hz. He said you want to lower the frequency as the Toroid ll will not saturate and provides a better impedance to the amplifier. They are plug and play ready. The interfaces have the following:
a) Large Type 2 Toroid
b) 36uf Jensen PIO capacitor
c) 12 Ohm Non-Inductive Wire Wound Resistor (High Power) replacing sand cast resistors.
d) Heat sinked 5 ohm metal film resistors in place of Brillance Pot
e) A couple inductors were also upgraded.
f) I had to put the 36uf Jensen PIO Capacitor, 12 Ohm Non-inductive resisotors, and the heat sinke 5 ohm metal film resistors in a computer box because of the size. Not pretty but it works.I will sell the panels for an additional 1K but I cannot ship them now. The oak frame is not in the greatest shape. I can send pictures of the interfaces if you provide an email. The interfaces are in Arizona, Phoenix area. Let me know if you have any questions.
Best Regards,
Gary
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