Friday, November 28, 2014

Marantz 1070 Integrated Amplifier

Marantz 1070
Heres a real early commission of a Marantz 1070 integrated, a neat design on a model you seldom come across.

Silmic II's and a FG were used on the power supply from a recommendation on this particular unit,H801 was a common cathode MUR1620 diode, where a 131B was. The, Adjustments were made at J810 & J811 adj. R807 to 40VDC initial 41.00V Reset to 40.00V. As much of the glue and so fourth cleaned off nicely.
A new EG1018-ND switch was placed with the safety cap across.

I used my typical assortment here, Nichicon muse for the bipolar's and WIMA's in place of the tantalums along with Silmics, again I recommend keeping the large brown films, unless a must some ECW PP's there. I think these selections really have some harmony here.

Silmic and WIMA's were again used here with transistors to bother on this model, a slight variations from the 845's with 0.00ma leakage and testing well.

The removal of the amp board can be tricky, but I found if you have the heatsink mounted SVT diodes and unscrew the rear panel you gain an easy access point. Silmic/WIMA and FG's were used along with a special Elna Cerafine, these are very nice, albeit pricey electrolytic. The bias and offset have pretty easy tap locations as well. New thermal compounds and mica were done as well just to freshen up the old stuff.
Idle Current Adj.
J714 & J716 adj. R733 to 10mv initial 10.5mv Reset to 10.00mv
J715 & J717 adj. R734 to 10mv initial 10.00mc Set
DC offset
J723 & J722(G) adj. R711 to initial 5.0mv Reset to 0.00mv
R724 & J722(G) adj. R712 to initial 3.5mv Reset to 0.00mv

The Main filter caps have a unique location mounted under the chassis on this model, these were replaced with two 10000uf 50V 
647-LKG1H103MESCBK Nichicon KG's. The higher capacitance leads to us to a more refined and deeper lower end.

A blue LED replaced the original yellow incandescent to give that typical  blue Marantz to match the owners Model 150 Tuner. 


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