To all and especially to Dave G and Larry...Thanks again for your willingness to share what you so expertly know about our gear. I was just thinking this weekend how far I've come in 1 year in my ability to work more comfortably (and knowledgeably) in the electronics/tube restoration world. I actually enjoyed studying the kx-200 schematic this weekend and reveled in being able to identify stages, components, signal versus power flows, and using components to adjust both signal and power flows. Although I'm still at the point where I need to follow others' step by step instructions and choices of which components to add, replace and remove, I'm making my best effort to UNDERSTAND WHY I'm replacing components and the effect of their different values.
I replaced diodes/rectifiers SD1 to SD 4 with 3A 1000v editions. I'm not sure, but I seem to have lost a little of the deep bass I so enjoy. And it seems I've lost some volume too. I'm having to turn the volume up to get the same punch I had before. The super clarity is still there. Overall I just love the sound of this kx-200. My poor 500-C has been sitting idle. I don't yet have a permanent location for the KX. Table space in my studio/office is extremely limited. I have to start thinking vertically !
This weekend I also added a second CL-80, this time on the fuse side of the incoming electric. I replaced 2 caps, C13, C14, in the tone stack with orange drops. They are .047uF, were 400v, I upped the voltage to 600v. I also replaced 2 caps in the phono preamp stage, C7, C8. One of them was pushing its upper tolerance limits. I replaced 2 lytics C25, C26, that were 50uF 70v, gave them some head room since they're right up front before everything - 100uF 100v. Like I said, somewhere in all of this I seem to have lost some deep bass. I would bet it has to be in the caps values. I know in guitar amps the combination of values of caps and resistors affect the cutoff/slope frequencies of bass, mids and trebles.
Still more to come... Replace can caps with Hayseed Hamfest products. Replace some missing screws, replace some damaged RCA jacks. Find a nice cabinet (I have some web sites marked). Adjust the phase inverters since I changed all the tubes. Maybe try some changes some other folks have done in other forums. Add EFB !!
Thorne
PS - I just replaced the bias meter resistor. Was 390 ohm. Replaced with 240 ohm 1/2 watt 5%.
PSS - I've been playing the KX all day. Missing deep bass? Not anymore. Tubes need to warm up? Just so happened the source material earlier today was weak? I love this KX !