Mike Mount
New Member
First off, I want to THANK PEOPLE HERE for sharing ideas and the images of this amp in its progression. I sold the entire Kenwood line in the late 70's - early 80's and was always fond of the KA-7100, but owned, built and modified Haflers in the day. I was always interested in this piece over the years and after researching a multitude of vintage gear the Harmon Kardons 330-430 receivers, select Kenwood Tuners and amps, and Hafler for separates. In the hierarchy, scheme of gear, there is symmetry in the voicing and sound. All very worthy of TLC only we might lavish on an old garage sale or Ebay relic. I always want to 'play' with vintage gear, but was afraid of the very thing that I am now completely taking head on. The OLD STUFF is cool but needs to be rebuilt, in most cases, not partially.
I came to Audiokarma, by a search about the KA7100. Read the blog, studied the (most excellent) pictures, circuit and layout. Mirrored that information with the excellent dialog here. Feeling confident, I bought (3) KA7100s, and 3 Kenwood tuners. I already had parts inventory, most of the parts which I have been using on other circuits (HK330c) it was very easy to proceed. The amp responded FABULOUSLY WELL!
My goals: use 3 units for circuit mirroring, easier to back track. Complete rebuild / test each in stages.
Update .every capacitor., full replacement to limit variability and parasitic failures.
Raise the voltage a level or 2. Raise the quality level 2-3 steps (audio grade caps)
consider raising the capacitance (if prudent) and bypass all critical caps,
especially those most immediate to the circuit.
I have used all the same parts across multiple tuners, receivers, integrated amps, pre-amps and power amps. I am hearing principle differences in the circuits and individual designs (not variations in parts) Essentially modeling each piece on the same development line. I have been building for 35 years, was a Musical Concepts dealer/reseller. Common sense in circuit optimization applies across all of these products - what works in one works in others, for the most part.
Nearly entirely power supply work. With extensive film bypasses. Used mostly Nichicon Muse throughout and in tight spaces the Fine Golds (main p/s, phono and pre-amp interstage coupling) I also experimented with quality, size, and voltage in the output section. I used all Wimas for all film bypasses and (most) filter networks. Higher voltage 6,800mfd/63 volt main p/s caps sounded much better, than with higher added capacitance alone... they are simply more relaxed sounding. I will always choose the higher quality part over higher value (EG: Jensen caps, in main p/s) budget permitting.
I will post some pictures and share, eventually. I appreciate the spirit of those here, you all that helped me immensely I was able to take a plunge and learn about these Kenwood models first hand here, with your objective commentary. I nearly want to downplay my enthusiasm publicly, as there may be a rush on these vintage gems. I have 3, and wonder if it is enough to last me a lifetime ;-) If I will ever where them out... they are so seriously 'overbuilt' now.
I came to Audiokarma, by a search about the KA7100. Read the blog, studied the (most excellent) pictures, circuit and layout. Mirrored that information with the excellent dialog here. Feeling confident, I bought (3) KA7100s, and 3 Kenwood tuners. I already had parts inventory, most of the parts which I have been using on other circuits (HK330c) it was very easy to proceed. The amp responded FABULOUSLY WELL!
My goals: use 3 units for circuit mirroring, easier to back track. Complete rebuild / test each in stages.
Update .every capacitor., full replacement to limit variability and parasitic failures.
Raise the voltage a level or 2. Raise the quality level 2-3 steps (audio grade caps)
consider raising the capacitance (if prudent) and bypass all critical caps,
especially those most immediate to the circuit.
I have used all the same parts across multiple tuners, receivers, integrated amps, pre-amps and power amps. I am hearing principle differences in the circuits and individual designs (not variations in parts) Essentially modeling each piece on the same development line. I have been building for 35 years, was a Musical Concepts dealer/reseller. Common sense in circuit optimization applies across all of these products - what works in one works in others, for the most part.
Nearly entirely power supply work. With extensive film bypasses. Used mostly Nichicon Muse throughout and in tight spaces the Fine Golds (main p/s, phono and pre-amp interstage coupling) I also experimented with quality, size, and voltage in the output section. I used all Wimas for all film bypasses and (most) filter networks. Higher voltage 6,800mfd/63 volt main p/s caps sounded much better, than with higher added capacitance alone... they are simply more relaxed sounding. I will always choose the higher quality part over higher value (EG: Jensen caps, in main p/s) budget permitting.
I will post some pictures and share, eventually. I appreciate the spirit of those here, you all that helped me immensely I was able to take a plunge and learn about these Kenwood models first hand here, with your objective commentary. I nearly want to downplay my enthusiasm publicly, as there may be a rush on these vintage gems. I have 3, and wonder if it is enough to last me a lifetime ;-) If I will ever where them out... they are so seriously 'overbuilt' now.
