scottyh777
Super Member
Actually not sold but donated to PIO1980 who is going to attempt to bring it back at least better than how I sent it to him.See below.
Mitsubishi LT-30 restoration
- Thread starter kotofei
- Start date
Actually not sold but donated to PIO1980 who is going to attempt to bring it back at least better than how I sent it to him.See below.
Pio1980
AK Member
So far I can say the base plinth isn't as bad as it looked in the pix, it's still structurally sound. Over cdx is very nice if not collector/museum quality, perfect for my purposes. I was able to reset tracking before it failed to re-initiate, I suspect default/reset hangup due to non-functional cueing and need to determine the belt size before disassembly, the main point of concern to me right now is that the servomotors should run briefly upon power-up to re-initiate and zero the servo systems if it works like every other servo system LT I've seen. Bulb lamps and headshells are already on order.
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Do the prism bulbs work? They were both blown on mine and they are 5v. All of the control panel bulbs in mine are original. I replaced the tracking bulbs without checking them.
If you have a capacitance meter, I'd be interested to hear what the total capacitance is from the tonearm through interconnects.
If you have a capacitance meter, I'd be interested to hear what the total capacitance is from the tonearm through interconnects.
Pio1980
AK Member
The prism lamps are good as are both tracking shutter lamps and the control panel indicators, so far the only lamp that may be out AFAIK is end-of-play. Since it's locked in cue-down I can probably check capacitance, BRB ----.
Ca 221pF each sans headshell with stock cabling and replacement plug-ends. That falls into what most MM/MI either want or tolerate, MCs are less affected by shunt capacitance but otherwise all things being equal it'll round off edges and roll-off the upper end vs less shunt cap.
My SL-1600MkII is ca 68pF each channel with muting ckt disconnected, stock cables and ends, no headshell.
Ca 221pF each sans headshell with stock cabling and replacement plug-ends. That falls into what most MM/MI either want or tolerate, MCs are less affected by shunt capacitance but otherwise all things being equal it'll round off edges and roll-off the upper end vs less shunt cap.
My SL-1600MkII is ca 68pF each channel with muting ckt disconnected, stock cables and ends, no headshell.
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I posted it here: http://www.audiokarma.org/forums/showthread.php?t=405707
Made a nice improvement in the sound.
Made a nice improvement in the sound.
+1. Great job by Aerobat!!
I have thought about re-wiring or a long time; however, I'll probably change both internal (i.e. in the tonearm) and external wires to the Cardas.
The other thing I thought about is to encapsule a muting board into some sort of grounded metal box. I have some hum off the Mitsu; the source is the CD player transformer.
BTW I changed the interconnectors to Petra at the time of the original restoration so I don't know if sound became better. However, changing ICs to Petras on TTs did improve sound.
I have thought about re-wiring or a long time; however, I'll probably change both internal (i.e. in the tonearm) and external wires to the Cardas.
The other thing I thought about is to encapsule a muting board into some sort of grounded metal box. I have some hum off the Mitsu; the source is the CD player transformer.
BTW I changed the interconnectors to Petra at the time of the original restoration so I don't know if sound became better. However, changing ICs to Petras on TTs did improve sound.
I'm having some hum issues as well (from before my re-wire). My other table doesn't do it and they're side-by-side, so it's something with the Mitsu.
Pio1980
AK Member
The Cart wires here are run with others in the carriage,
I'd think they should be separated.
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Oddly, my LT-30 makes a light buzzing sound regardless of whether the ground is connected to the preamp. In fact, grounding it or not makes absolutely no difference in the noise level.
Holding the ground wire between my fingers reduces the buzz though.
Edit: I found out why I was having a grounding issue. My phono pre, a Pearl 2, reverses phase as part of its design. I had reversed the polarity of the cart leads, and this caused the problem. Putting the leads back to proper polarity eliminated the buzzing sound.
In another post Steve had said that he can hear reversed absolute phase -- so far I haven't been able to tell the diff.
Back to your regularly scheduled thread...
Holding the ground wire between my fingers reduces the buzz though.
Edit: I found out why I was having a grounding issue. My phono pre, a Pearl 2, reverses phase as part of its design. I had reversed the polarity of the cart leads, and this caused the problem. Putting the leads back to proper polarity eliminated the buzzing sound.
In another post Steve had said that he can hear reversed absolute phase -- so far I haven't been able to tell the diff.
Back to your regularly scheduled thread...
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Pio1980
AK Member
The bulbs from dwojo and headshells from Musician's Friend came in, the el-cheapo Technics knock-off headshells are really quite decent and a real bargain. No adjustable azimuth at this price level just as with the originals, my alternate lo-mass composite headshell is azimuth-adjustable. Waiting on belts and the Cardas signal wire for the carriage-to-terminal block run. My main concern is that the lift motor may be NF /burned up from a false default cdx under which it may have constantly ran while the TT was being used in such a state unknown to prior users.
Perhaps, they could be replaced with shielded wires?
I saw Cardas shielded wires for sale; however, don't remember at what store.
I saw Cardas shielded wires for sale; however, don't remember at what store.
rnorton
Super Member
Reversed absolute phase is most evident in trumpet solos and male vocals, both of which are asymmetrical waveforms with a negative half that exceeds the positive half.