AU Alpha 707 L Extra - PSU caps upgrade - I need input

[Fitap]

Hi to all and sorry for my english is not good.

I own of a vintage japanese market AU Alpha 707L Extra model, and I looking for the service manual for read the part list because I wish to upgrade the electrolytic capacitors of power supply.

But a bit confused when I inspect the PSU; there are 2 big caps of 63mm x 80mm what I have to replace 1:1 with Nichicon KG series Super Through (I hear suggestions for others brands, but they must fit into the clamp) and I found what there are two diferent brands and values of the capacitors into, one is of 12000 uF 80 Vdc Gold SupplY brand and the other one is of 6800 uF 80Vdc Pure Focus brand. Like a said, both are diferent brands and diferent values.

Also another upgrade into PSU I like to do are the diodes, mainly the bridge diodes.

Anyone can confirm what I comment is alright? May be the gear have a bad service prior?

The poweramp is working today, the sound is amazing, I have done a full recap with a good technician in my country, using caps Nichicon, Elna, etc, all of them audio grade.

I'm was impossible to find the service manual, I know what the electronic in domestic japanese market are diferent of international market, ins't?

Thanks for reading and I apreciate any input.

My best.

pd. here some pics

 

[Hipocrates]

But a bit confused when I inspect the PSU; there are 2 big caps of 63mm x 80mm what I have to replace 1:1 with Nichicon KG series Super Through

I would say looking other alphas that 80V and 12000uf to 15000uf are going to work ok. Brands? United Chemicon, Panasonic, Kemet, CDE will do. and I pretty sure they will fit.... I would not worry about the rectifiers unless you see something fishy.

 

[pete_mac]

Those capacitors are the original capacitors for the 707L Extra - in the JDM models, Sansui used two different values and types of capacitors in many of the 707 series, all the way up to the MR series.

Personally, I would not change the filter caps in the Alphas unless they are faulty (and that advice is coming from someone who tends to replace every capacitor that he looks at!). They are exceptionally good capacitors and are not prone to failure.

 

[Hyperion]

Personally, I would not change the filter caps in the Alphas unless they are faulty (and that advice is coming from someone who tends to replace every capacitor that he looks at!). They are exceptionally good capacitors and are not prone to failure.

Quoted for truth.

 

[Hipocrates]

The reason I thought it was a good idea is because I thought, that Sansui used Nichicon 12000uf 63V for power supply filters on those type of units, not ''Pure Focus'' and "Gold Supply" 80V caps

 

[Fitap]

Thanks for replies guys.

I would say looking other alphas that 80V and 12000uf to 15000uf are going to work ok. Brands? United Chemicon, Panasonic, Kemet, CDE will do. and I pretty sure they will fit.... I would not worry about the rectifiers unless you see something fishy.

I agree, and just wondering wich is the reason to use diferent values? enginering desing?

Those capacitors are the original capacitors for the 707L Extra - in the JDM models, Sansui used two different values and types of capacitors in many of the 707 series, all the way up to the MR series.

Personally, I would not change the filter caps in the Alphas unless they are faulty (and that advice is coming from someone who tends to replace every capacitor that he looks at!). They are exceptionally good capacitors and are not prone to failure.

I agree too, but is to hard find the part list to know if they are the sansui's stock.
The japanese market are diferent from other market, like international market? in japanese market they put better goods?

The reason I thought it was a good idea is because I thought, that Sansui used Nichicon 12000uf 63V for power supply filters on those type of units, not ''Pure Focus'' and "Gold Supply" 80V caps

In this case both of them are 80 Vdc, with those values and brands what you said.

Like I posted above, the 707L extra I did a full signal recap, It's working today and the sound is amazing, with a good depth, wide, separation instruments and 3D image stereo.

Only think what is appropriate upgrade the PSU and the signal cables also.

Best regards

 

[Hipocrates]

Only think what is appropriate upgrade the PSU and the signal cables also.

Those are Nichicon, terrific caps as Pete said (he's a real expert)... Just enjoy your unit and start to look for the next project.

 

[pete_mac]

The reason I thought it was a good idea is because I thought, that Sansui used Nichicon 12000uf 63V for power supply filters on those type of units, not ''Pure Focus'' and "Gold Supply" 80V caps

No, they didn’t use 12000uf caps in any of the 707s - the 607s used a pair of 10000uf or 12000uf caps depending upon the exact model.

Thanks for replies guys.

I agree, and just wondering wich is the reason to use diferent values? enginering desing?

I agree too, but is to hard find the part list to know if they are the sansui's stock.
The japanese market are diferent from other market, like international market? in japanese market they put better goods?

Here's an example from the service manual for the 607/707/907MR/MRX models. The same general design features and topology carried through from the earlier 707 models to the later models.

MC11 and MC12 are the filter caps on the 707. There is a variation in MC11 depending upon whether it is the Japanese MR model (00) or the international MRX model (XX). The MR has one 8200uf Gold Supply and one 5600uf Pure Focus, whilst the MRX has a pair of 8200uf Gold Supplies.

The 907MR and MRX also have different filter capacitor values, consistent with the above.

The use of two different capacitors on the Japanese models was a design choice by the Sansui engineers - they always did things for a reason, particularly in their Alpha series of amps. Personally, I would trust their judgement

 

[Hipocrates]

used a pair of 10000uf or 12000uf caps depending upon the exact model.

Cool stuff, thanks for the clarification man.

 

[Fitap]

Thanks a lot @pete_mac for the explanation.

I follow your recommendation and it will be remained like are designed.

Regards.