As a general rule, the signal path capacitors will be subjected to lower voltages than the power supply capacitors. The polyester stacked film capacitors are typically available rated at 50V or 63V. For the polypropylene capacitors, use the smallest capacitor that will fit the available board space (which is often the lowest voltage rating). For C0G capacitors you can use 50V or 100V rated ones.
Generally, your parts order is OK. But I did notice some possible issues:
If I understand your question correctly, you are asking if increasing the capacitance value from the stock value is permissible. In the vast majority of the cases, there is no problem increasing the capacitance rating of the local decoupling capacitor, especially for small values less than 1000µF. IMO, a 2X-3X increase is acceptable for most small capacity capacitors whose purpose is solely DC filtering. In these cases, the extra load on the power supply transformer and diodes is minimal. However, the extra load would be a consideration when large main power supply capacitors are to be replaced; in that case, a more conservative approach is warranted, e.g., the stock main filter capacitors for the AU-717 are rated at 15,000µF and increasing them to 18,000µF (a 20% increase) would be acceptable, but beyond this value may be inviting problems.Very good. But how do you account (or allow) for higher uf values when the factory assigned the values that were in there? Higher voltage is one thing. But uf value is another.
On the F-2720 board, the capacitors C15 and C16 were replaced with audio grade types (Silmic II, 10µF/35V). In a blow-up of the original picture below, you can see the capacitor C15. But it was inadvertently not mentioned in the accompanying text. Regarding C21,C22,C45 and C46, use the 10µF/25V or 10µF/50V that you have on hand.
There isn't really enough room for large polypropylene film capacitors as replacements for C27/C29 and C28/C30 on the F-2723 board. However, 4.7µF stacked polyester film types (e.g., WIMA MKS2 or Kemet R82) will fit in the space originally occupied by the C35/C36 polyester bypass; see earlier post #20 for picture. Alternatively, a single 4.7µF Nichicon ES bi-polar electrolytic capacitor can be used to replace the original polarized capacitor pair and the by-pass kept.
The impedance of the power amplifier is 50kohm, and with the 5.0µF electrolytic capacitors in the high pass input filter, the F3 is 0.64Hz; with the replacement 2.2µF film capacitors, the F3 increases to an inconsequential 1.45Hz.
Part 3: Driver Circuit Board (F-2721 & F-2722)
The capacitors (C02, C04) which shunt the 22V zeners were originally 33µF/25V; the replacements were low ESR types rated at 100µF/35V. Also, the zeners (ZD01, ZD02) themselves were replaced with 22V/1.3W types (BZX85C22). The local decoupling capacitors C11 and C14, originally rated at 470µF/63V, were replaced with 1000µF/63V low ESR types. The C12 capacitor was 1µF/50V and was replaced with a low ESR type of the same value. The variable resistors VR1, VR2 and VR3 (100ohm, 2.2kohm and 1kohm, respectively) were replaced with Bourns single turn cermet types. The failure-prone 150ohm fusitors (R23 & R25) were replaced with 150ohm/0.25W metal film resistors. The negative feedback resistor (R16) was also replaced with a 27.4kohm/0.5W metal film resistor.
A couple of additional components were also replaced due their proximity to the C11 or C14 capacitors that were attached to the board with the corrosive glue: R15 (10kohm) was replaced with a same value 0.25W metal film resistor on F-2721 and D02 (1S2473) was replaced with a 1N4148 diode on F-2722.
Discrepancies between the Sansui schematics and the actual physical circuit are rather common. In most cases it is due to changes during the production run. I think that you are referring the R32 and not R34. The 0.33µF film capacitor across R32 is stock (I did not add this capacitor). As for R32, but I cannot confirm that it is 180ohm or 270ohm (since I don't have any pictures that show this clearly and the unit is back with its owner).
