Monday, August 17, 2015

Marantz 1030 Integrated Amplifier

Marantz 1030 Integrated Amplifier

The Marantz Integrated Amplifiers happen to be one of my favorite 70's Marantz pieces. Being a big fan of the 2230 similar 1060 Integrated, I knew id love the like sound of the 1030 Integrated. Rated at a conservative 15 Watts a channel, the 1030 uses a very similar pre-amplifier topography again as the 1060. The phono stage features shielding I haven't seen yet on any 1060's either.

Power Supply;
The regulated 35V+/37V+ power supply is fairly straight forward on this model, replacing electrolytics with high temp, long life Panasonic FR/FC's. Several Carbon Composite resistors were replaced as well with MOX Flame-Proof, all glue was removed. 

The filter caps in these are positioned smack in front of the amplifier sections, which of course is a source of significant radiant heat. I like to come back, same with 22XX receivers who position these against driver sections, but I like to install a smaller foot print electrolytic here. This increases the overall area around the drive boards and decreases the subjected heat these caps experience. I increased the values  here past the 20% extreme at 4700 for 2200 and 6800 at 4700's microfarads. To finish up a new 7A EG1018 power switch and X1Y2 rated safety capacitor was installed.

Again, with such a close topography minus the 1st stage, to the bigger 1060 Integrated I want with a similar compilation. Using low impedance PW's and Elna Silmics and small values with WIMA film capacitors. the coupling stage original Mylars were replaced with a Polypropylene MPK Solen. 

Marantz 1030

Marantz 2230

The phono stage was similar to others, updating 2SC458 Bi-Polar Transistor pairs to KSC1845's and Elna Silmics/PW's. Its important to notate that C909/910 is an axial type electrolytic shunted with a 100ohm 1/4W resistor to ground. 

Driver Stages
One important update to perform on the the symmetric driver stage is the H715/716 Diodes (1N60) to a series of 1N4148 diodes for reliability and adding Bourns Precision 500/100K trimmer potentiometers. Differential Pairs to matched Hfe 1845's. The coupling C725/26 and 01/02 were upgraded with polypropylene Solens and WIMA MK film capacitors, Elna/PW's were used for electrolytics throughout. 


Several variations on output devices were tried and tested due to a repair required. original TO-66's are hard to come by, I recommend for a different option using MJE15032 NPN TO-220 type BJ-Transistors if necessary with some slight heatsink modifications and SilPads. 

Friday, August 7, 2015

Infinity Quantum 5 (Q5) Speakers XO Rebuild

Infinity Quantum 5 (Q5) Speakers

I wanted to come back to a pair of speakers we had in a few months ago.

This is a pair of Infinity Quantum 5's. These are beautiful speakers, with an interesting L-style metal pedestals thats factory and a neat elevated grill snap. These are rated at a nominal 4 ohm load with a driver range of 30-250Watts (38-32KHz +3dB)

One major thing I'd like to highlight on the Quantum series are the EMIT tweeters. Now I absolutely love how these sound, but I haven't come across such a delicate tweeter in my life. At this point in their lives many have started to delaminate the VC tracing from the diaphrams. Another issue with the EMITs are the solder pads for connections, many have developed bad solder joints and simply reflowing will get ya back to reading proper ohms. Thats not to say their bad, the electrostatic design and extreme Cobalt magnetics are nothing to scoff at. 

The lower frequency driver is a dual voice-coil Watkins driver, these are phenomenal drivers that were built like tanks.  The midrange driver is a poly type dome construction sweeping from 600 to 4KHz<.

The bug with these speakers is to pull the EMIT and test them, reflow if necessary and attack the cross-overs. They use two pretty well constructed standard can type electrolytics along with an array of film polypropylenes, three inductors, rheostat and phenolic potentiometer.  The can type electrolytics were replaced with two axial electrolytics in parallel to obtain the correct value, all the original films were replaced with a much higher quality Solen MK type polypropylene capacitor in a similar fashion. (XO Points of perception 600Hz,4kHz)

**one major notation I want to add is the fuse, do not use the original rated value, I highly recommend .5-.750mA fuse as really anything over and you can say good bye to those EMITs.



With correct placement and proper drive these truly sound amazing before and after. They look just stellar with a proper cleaning and the heavily constructed metal pedestals.