Quad 707 improvements.

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10-Jul-2018 05:04 PM

Not Available

Posts: 3

Hi, i'm new to the site and have registered so i can learn about potential 707 upgrades. I already like the sound it produces through my Monitor Audio Studio 50's but would like to get the amp upgraded. What would be the ultimate 707 upgrades and would these upgrades significantly improve on the sound quality? There are several companies offering these services but which offers the best sound for pound upgrades? Thanks. 

Regards Mark.


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13-Jul-2018 02:05 PM

circlotron

circlotron

Posts: 8

My 707 had bad electrolytic caps on the PCBs due to age. Their ESR was very high when measured with an Atlas ESR meter. They looked OK physically though. I would suggest starting there.
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13-Jul-2018 04:53 PM

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Posts: 3

Thanks, what would be the best recommended quality caps to buy? I'm complete new in all this modifying. My amp has developed a dry joint in the power input on the amp at the back. So i'm thinking while in there i want to get it serviced with high quality parts and perhaps take in the best upgrades known to improve on the amp.   

What does Dado offer? 

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14-Jul-2018 03:10 AM

circlotron

circlotron

Posts: 8

I like Nichicon and Elna for durability. Panasonic and Rubycon are good as well.
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06-Sep-2018 03:11 AM

Not Available

Posts: 3

I guess from the serious lack of response to this i might as well move on to another amplifier as no one here has any passion for the 707.  

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06-Sep-2018 02:58 PM

circlotron

circlotron

Posts: 8

I'm really happy with my 707. I replaced all the electrolytic caps and removed the Quadlink PCB. Also added a 0.1uF C0G bypass cap on the V+ terminal of the Op-Amp and replaced the V- bypass with another 0.1uF C0G. Also replaced the 270pF radial ceramics with C0G.
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07-Sep-2018 02:23 AM

circlotron

circlotron

Posts: 8

I should have said I replaced the 330pF axial ceramics (not 270pF radial) with C0G (3 per channel). Also, the rubber insulators on the RCA jacks were deteriorating. I replaced those with some Switchcraft S1564 fiber shoulder washers. I did need to sand the washers down a bit as the washers were designed for a thicker panel. The coax from the Quadlink PCB to the amplifier PCBs was getting brittle so I replaced that with some RG-174 FEP coax.
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16-Sep-2018 05:44 PM

Fabian

Fabian

Posts: 55

Did you check the download section? There you'll find the Dada revision manual which is for 606, 707 and 909.

It's main target is to replace components that have sufferd from aging. There are a few modifications that can be seen as an "upgrade", too. How much of a difference you will notice will at least partly depend on how the current condition of your amp is.The revision manual also contains recommendations for the caps to use. Ready-made kits are available from dada.

All electronlytics are prone to aging, but tolerances and differing usage patterns will speed up or delay this process. OTOH it is pretty save to say that 20+ year old amplifiers will benefit from replacing them.

This forum is operated by Dada Electronics. From my experience their services offer the best sound per pound.

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