I have successfully converted from 100V to 230V replacing the transformer. Although I couldn't get Cleem Linear Transformer 1.5VA-3512 series, I was able to get a similar transformer.
Meanwhile, it isn't possible to get a 230V rated board (716-0962-07?) from the Accuphase factory. I have successfully converted to 230V without a 230V rated board (716-0962-07?).
Thank you for the photo. I googled the label "HPT 3512-5" on the transformer and found the Cleem Linear Transformer 1.5VA-3512 series. You will need to replace it with a transformer rated for 230V. There are a lot of uninstalled components on the board (716-0962-01) and I assume the circuit complies with EU regulations and powers down after a period of inactivity.
I think it would be best to order a 230V rated board (716-0962-07?) from the Acuphase factory to replace the 716-0962-01.
Sorry, I can't clearly see and identify any components in the photo due to obstruction of wires. Can you post some clearer photos showing the auxiliary transformer? Is that power switch assembly board?
Meanwhile, do you think it is OK to change only connecting J3, J6? Or do I need to change other boards like the sub-transformer board?
Sorry for my ignorance, since the preamp doesn’t have a standby/power-on function, I didn’t know there was a sub-transformer board in it, could you post a photo of such a board?
By the way, always test with a DBT (Dim Bulb Tester) after voltage conversion to avoid any surprises!
Because of I don't have the preamp on hand, I can only assume it's a 100V, 120V and 230V multi-tap power transformer. The voltage settings are as follows:
J1, J4 = 100V
J2, J5 = 120V
J3, J6 = 230V
However, according to the brochure of C-2300, it is marked as 120V, 220V, 230V AC (voltage is shown on the rear panel). If so, connecting J1 and J4 will be 120V, connecting J2 and J5 will be 220V, and connecting J3 and J5 will be 230V. Please post your findings, thank you.
Thank you for providing the transformer spec. Sorry, I don't know the output voltage of the transformer, maybe @foolishman has measurements.
However, I remember there was a post from an old thread mentioned that the relay was a 18VDC relay, so I'm guessing the output voltage of the transformer is probably about 13.6 to 14V.
If you decide to convert the voltage to 230V, please post your findings and some pictures of the voltage conversion, I'm sure Audiogon forum members who want to do something similar will find your post helpful and appreciated.
Looks like there are a lot of transformers available that will fit this package format from various manufacturers with a good selection of output voltages.
I'll continue to use my amps with a step down transformer for the moment, but think I will have a look at converting to 230V sometime in the next few months as it sure would be more convenient.
Has anyone measured the output voltages from the transformer, do you know?
just what would I install on J2, as it only has a single tab.
716-1374-01 is a soft start resistor board. Based on my previous experience, two sets of resistors are connected in parallel via J1 and J3 (100/120V setting), and two sets of resistors are connected in series via J2 (220/240V setting).
I believe that the standby circuit transformer has 3 pins on one side and 4 on the other. Does this suggest that it may be a center tap so can accommodate both 100V and 230V? It just needs wiring up differently.
Sorry I don’t have an A-48S in front of me, I just based it on the photo provided by @foolishman, if the transformer does have a multi-tap primary winding, that would make voltage conversion much easier!
Can you post front and back pictures of your #716-0962-01 board?
how would I go about finding a replacement transformer?
This is the real challenge! Measure the secondary winding voltage, transformer size and its pin spacing, search for 230V versions on Digikey, Mouser, etc.
I might be a bit slow, just what would I install on J2, as it only has a single tab.
Also, I believe that the standby circuit transformer has 3 pins on one side and 4 on the other. Does this suggest that it may be a center tap so can accommodate both 100V and 230V? It just needs wiring up differently.
Not being experienced, how would I go about finding a replacement transformer?
there's another way to convert to 120V, which is to swap the positions of the orange and yellow wires and swap the positions of the brown and black wires. Do you think it is OK?
Yes, both the 100V and 120V setups have the two primary windings in parallel, swapping the position of the orange and yellow wires and swapping the position of the brown and black wires should also work.
Thank you very much for providing information on how to convert 100V to 120V. I have done accordingly, and I confirm I have successfully converted voltage to 120V. According to my friend, there's another way to convert to 120V, which is to swap the positions of the orange and yellow wires and swap the positions of the brown and black wires. Do you think it is OK?
Accuphase products are certainly state of the art in terms of build and design, and if pricing was more affordable outside of Japan, I think more Accuphase enthusiasts would be able to enjoy it.
Thanks for the photos, this time Accuphase is using a PCB instead of terminal block like before. Its connection method is still the same.
Looks like your friend already understands how these connectors work! Simply swap the positions of the black and yellow wires and swap the positions of the brown and orange wires to convert the power transformer primary winding from 100V to 120V.
On the #716-0962-01 board you will need to replace the small 100V transformer with a 120V one, or simply use a resistor to drop the input voltage.
IMHO, Accuphase products are certainly state of the art in terms of build and design, and if pricing was more affordable outside of Japan, I think more Accuphase enthusiasts would be able to enjoy it.
Since it's not easy to pull out the transformer wires (although I know I must pull out the transformer wires when I actually do conversion), a friend of mine who is familiar with PCB of electronics arranged an image which explains the connector layout for me.
Thank you for your valuable opinion. I have no intention of opposing it or arguing with it. Let's get along, anyway. What I am interested in is only quality of sound.
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