700 Series II Build

[Hexis22]

Fully assembled, meters calibrated, output power confirmed with symmetrical clipping, and initial listening tests completed.

Time to move into main listening room for the real sound performance evaluation.

I now have a completed pair of 100% hand assembled, upgraded, and restored matching Black beauties...

 

[bscote]

Finally getting around to building myself a 700 after finding a Series II with functioning donor components, not the best cosmetically but will do given the price.

After finishing a 700B for a customer, I'm looking forward to having a 700 to use when I want a concert in my living room. I also liked the front panel On/Off and meter sensitivity switch features.

I will most likely update my 400 S2 with a meter sensitivity switch as well. I call it the Wife sensitivity switch, the meters don't usually move much when she's home...

I plan a full White Oak upgrade including new chassis and faceplate.

Here is what I have to work with, it's all stock except a large variation of replacement outputs with SIL pads AND thermal grease:

The good thing is that that amp is the full complementary version. Did you use the original output transistors?

 

[Hexis22]

The good thing is that that amp is the full complementary version. Did you use the original output transistors?

Absolutely not!

 

[bscote]

Absolutely not!

Okay, what outputs did you go with? And how is it all working out so far?

 

[bscote]

Wired up and passed all bench testing.

Time to button everything up and start playing the sweet sound of music.

That is some truly beautiful work you did with the installations and wiring!

 

[Hexis22]

That is some truly beautiful work you did with the installations and wiring!

Thank you.

White Oak offers new ON Semi output drivers (MJ21195G, MJ21196G) at competitive pricing.

https://www.whiteoakaudio.com/estore.aspx

The White Oak backplane boards are only full complementary output by design.

Highly recommend replacing 40 year old output drivers due to unknown history, thermal cycling, and significant improvements with modern materials and manufacturing techniques with new devices.

 

[laatsch55]

Not to mention lower distortion and being an audio dedicated part..

 

[MusicSteve]

Fully assembled, meters calibrated, output power confirmed with symmetrical clipping, and initial listening tests completed.

Time to move into main listening room for the real sound performance evaluation.

I now have a completed pair of 100% hand assembled, upgraded, and restored matching Black beauties...

Looks Cool
Did you buy new Volume Knob? if yes do you have a part Number?
thanks
Steve

 

[Hexis22]

Looks Cool
Did you buy new Volume Knob? if yes do you have a part Number?
thanks
Steve

Many options on Amazon.

This is the knob used: https://a.co/d/janaNfF

 

[MusicSteve]

Many options on Amazon.

This is the knob used: https://a.co/d/janaNfF

Thanks, The more options the better
Anyone have a replacement for the Original one?

 

[Gepetto]

Many available options are 6mm, not 6.35mm and need to be bored out to fit 1/4" diameter pot shafts.

 

[Hexis22]

Yes, every option I’ve found required drilling out to fit 1/4” shafts.

 

[Loggitie]

Beautiful work, I'm impressed !

 

[Hexis22]

Beautiful work, I'm impressed !

Thank you.

You will enjoy upgrading your 400, they are very gratifying projects.

 

[Pulpmillguy]

Yeah...I know...

I wonder if taking it outside and using the high pressure washer would work...but I love the idea of the natural gas condensate, sounds like some REALLY good shit...I used brake cleaner when I did my 700 and it worked pretty well.

 

[Pulpmillguy]

Chassis assembly has started.

Going with a barrier terminal block for terminating the transformer.

Edit: In true Phase Linear fashion, this transformer was wired with the solid conductors closest to the core. All others I've worked with had the striped wires at the core. I guess I should not be surprised, considering it was most likely not specified combined with the use of non-polarized plugs at that time.

Drilled out and chamfered all heat sink TO-3 mounting holes for correct aliment with chassis.

Started AC wire routing and incorporated one of Don's Triac power switches.

Lots of fun new updates on this build...

Pretty slick how you used the spade fittings on the xfmr leads at the bridge...wouldn't have thought to do that instead of soldering...maybe next time

 

[Gepetto]

Pretty slick how you used the spade fittings on the xfmr leads at the bridge...wouldn't have thought to do that instead of soldering...maybe next time

The snubber board was designed with that in mind. The snubber was designed for the Model ONE that uses Faston connectors on all the wires attached to the bridge.

 

[Hexis22]

Pretty slick how you used the spade fittings on the xfmr leads at the bridge...wouldn't have thought to do that instead of soldering...maybe next time

I typically prefer direct solder terminations, but the wires gauge size of this transformer was cleaner to terminate with a Faston connector.

 

[Dnspy007]

Finished switch updates today.

Replaced both power and meter sensitivity switches and mounted to mid-plate bracket after marking and drilling 2 new holes.

Finished switch updates today.

Replaced both power and meter sensitivity switches and mounted to mid-plate bracket after marking and drilling 2 new holes.

I sure would like get a few of those, would you happen to have a part#

 

[Hexis22]

I sure would like get a few of those, would you happen to have a part#

Found on ebay:

https://www.ebay.com/itm/252661219693