Hello,
Yesterday I took the bottom off my old turntable to see why the left channel doesn't play after years of non use and two moves. I finally installed a new cartridge (Shure M97 X) that I bought years ago when I put it away in anticipation of when I set it up again. The previous Shure V15 III was fried.
So I tested the ICs from the RCAs to where they are soldered to a PCB that also connects to the fine wires from the tonearm/headset. One had no connectivity so I suspect the jack is bad (very cheap and boney wires).
So should I solder on new RCA jacks to the old boney wire or replace both ICs with a ground wire back to the pcb (this looks like very delicate work and easy to ruin)? I searched the Internet for hours looking for something like this (kit or whatever) and nothing for Technics except SL1200/1210 and that looks different.
So if new cables are the answer, what should I use. I am trying to not spend more than $50 as the TT isn't worth a huge investment. The cartridge is new and about $100 so I would fix it to get the use from that. I hope many of you have experience with this Technics setup and can make great recommendations!
I look forward to my cheap TT making my CD Players disappointing again! Thanks!
Regards//Keith
Yesterday I took the bottom off my old turntable to see why the left channel doesn't play after years of non use and two moves. I finally installed a new cartridge (Shure M97 X) that I bought years ago when I put it away in anticipation of when I set it up again. The previous Shure V15 III was fried.
So I tested the ICs from the RCAs to where they are soldered to a PCB that also connects to the fine wires from the tonearm/headset. One had no connectivity so I suspect the jack is bad (very cheap and boney wires).
So should I solder on new RCA jacks to the old boney wire or replace both ICs with a ground wire back to the pcb (this looks like very delicate work and easy to ruin)? I searched the Internet for hours looking for something like this (kit or whatever) and nothing for Technics except SL1200/1210 and that looks different.
So if new cables are the answer, what should I use. I am trying to not spend more than $50 as the TT isn't worth a huge investment. The cartridge is new and about $100 so I would fix it to get the use from that. I hope many of you have experience with this Technics setup and can make great recommendations!
I look forward to my cheap TT making my CD Players disappointing again! Thanks!
Regards//Keith
Hi sq225917,
Just checked from the pins in the headset to the PCB and they are fine (thank Heaven). They would be a mess to fix. So the problem definitely lies between the PCB and the RCA Plugs (basically the ICs) and I am inclined to think the wire was torn upon removing the RCA plug from the Preamp. Easy fix with new and better plugs but I am thinking that new ICs might sound even better. This is where I could use some direction from someone with this experience. Thanks!
Regards//Keith
Just checked from the pins in the headset to the PCB and they are fine (thank Heaven). They would be a mess to fix. So the problem definitely lies between the PCB and the RCA Plugs (basically the ICs) and I am inclined to think the wire was torn upon removing the RCA plug from the Preamp. Easy fix with new and better plugs but I am thinking that new ICs might sound even better. This is where I could use some direction from someone with this experience. Thanks!
Regards//Keith
Sorry, I fail to understand how an IC in a turntable may affect the sound?
It's only purpose is to lock the speed of the platter!
Best you just fix the plugs/cable and stick with the original ICs.
Spend the effort and money on parts that make a difference, like the phono preamp!
All the best and have fun listening! Hannes
It's only purpose is to lock the speed of the platter!
Best you just fix the plugs/cable and stick with the original ICs.
Spend the effort and money on parts that make a difference, like the phono preamp!
All the best and have fun listening! Hannes
Ah sorry I see!
Well, if you're a cable believer, feel free to do so! (No pun intended ;-))
I don't know wether the cable just goes to a terminal on the back of the turntable or wether the cable goes directly to the phono pre.
In case the cable goes from the turntable internals to the phono pre I just can strongly recommend you that you keep an eye on the capacitance of this cable!!
Moving magnet cartridges are depending on the exact value of capacitance to work properly!! That means to give a neutral frequency response.
For every single mm-cartridge the manufacturer recommends a capacitance which includes also the value of the cable. These values are around 100-200pF and are often already provided by the cable alone! Typ. values of cables are around 100pF per meter!
If you don't keep an eye on this you'll wonder why mms sound that bad (no heights, too much heights) and convert unnecessarily to MCs which are less sensitive on capacitance (but have other troubles).
All the best and please let me know in case I expressed myself not understandably, Hannes
Well, if you're a cable believer, feel free to do so! (No pun intended ;-))
I don't know wether the cable just goes to a terminal on the back of the turntable or wether the cable goes directly to the phono pre.
In case the cable goes from the turntable internals to the phono pre I just can strongly recommend you that you keep an eye on the capacitance of this cable!!
Moving magnet cartridges are depending on the exact value of capacitance to work properly!! That means to give a neutral frequency response.
For every single mm-cartridge the manufacturer recommends a capacitance which includes also the value of the cable. These values are around 100-200pF and are often already provided by the cable alone! Typ. values of cables are around 100pF per meter!
If you don't keep an eye on this you'll wonder why mms sound that bad (no heights, too much heights) and convert unnecessarily to MCs which are less sensitive on capacitance (but have other troubles).
All the best and please let me know in case I expressed myself not understandably, Hannes
Hi Hannes,
Thank you for helping me to understand better the dynamics of what helps and hurts the TT to sound better. I understood just fine!
This was not an expensive TT. It was $150 USD or maybe less in 1978. It doesn't do anything exceptionally well like more expensive TTs but it doesn't really do anything bad either. Plus it is a reliable workhorse.
The cables from the TT to any Preamp are what is in question. At one end are the traditional cheap plastic RCAs attached to cheap shielded cable (0.1 inches in diameter), that are attached at the other end to a PCB inside the TT where they are soldered. The wires from the Tonearm/Headset are also soldered to this small PCB, so the PCB is the interface between the Tonearm and the Cables and the Internal Ground.
Capacitance, this is why I was asking if there was a kit to replace the cables that was already designed to keep all the values where they would allow the TT to perform best (at a reasonable cost). OR someone with experience on these to tell me what they designed/used with the same issues in mind. I don't have any equipment to measure Capacitance. Also, I didn't know what value I needed to be with a MM cartridge. (thanks Hannes).
So that is why I am here, but I am getting the feeling that I should just cut off the old RCAs and solder on some better new ones!
Regards//Keith
Thank you for helping me to understand better the dynamics of what helps and hurts the TT to sound better. I understood just fine!
This was not an expensive TT. It was $150 USD or maybe less in 1978. It doesn't do anything exceptionally well like more expensive TTs but it doesn't really do anything bad either. Plus it is a reliable workhorse.
The cables from the TT to any Preamp are what is in question. At one end are the traditional cheap plastic RCAs attached to cheap shielded cable (0.1 inches in diameter), that are attached at the other end to a PCB inside the TT where they are soldered. The wires from the Tonearm/Headset are also soldered to this small PCB, so the PCB is the interface between the Tonearm and the Cables and the Internal Ground.
Capacitance, this is why I was asking if there was a kit to replace the cables that was already designed to keep all the values where they would allow the TT to perform best (at a reasonable cost). OR someone with experience on these to tell me what they designed/used with the same issues in mind. I don't have any equipment to measure Capacitance. Also, I didn't know what value I needed to be with a MM cartridge. (thanks Hannes).
So that is why I am here, but I am getting the feeling that I should just cut off the old RCAs and solder on some better new ones!
Regards//Keith
Ok I understand better now.
First let me say that the Technics is a perfectly fine turntable that to replace with something similar performing is very hard today.
Further don't forget that 150$ 30 years ago are a lot more today (inflation) and in addition production costs were far lower back then because the production volume (number of produced/sold units) was extremely much higher than today. Today this is a tiny market not even of interest to the big players.
No need to talk smallish about your technics!
Now to the interesting part of my posting:
Tell me your cartridge and I'll try to find the capacitance recommendation of its manufacturer (or ask people that might know), so that you have a basis to decide.
Further I would recommend that - in case you still want to replace the cable+plugs - you use a cable with a capacitance of about 100pF/m and use 1m length of it.
2nd it would be necessary to know how much capacitance is on your phono preamp input (usually stated in the technical details of your pre, usually in the owner's manual).
Then you know how much in total (you just need to add these 2 numbers) you have.
Increasing it is not the problem (if you have switchable capacitance, you can select anyway, otherwise you can just solder in additional capacitance), decreasing is not possible. That's the reason why I recommend 100pF/m and 1m length. Depending on your phono pre this is a solid figure to start.
All the best and have fun with your technics, Hannes
First let me say that the Technics is a perfectly fine turntable that to replace with something similar performing is very hard today.
Further don't forget that 150$ 30 years ago are a lot more today (inflation) and in addition production costs were far lower back then because the production volume (number of produced/sold units) was extremely much higher than today. Today this is a tiny market not even of interest to the big players.
No need to talk smallish about your technics!
Now to the interesting part of my posting:
Tell me your cartridge and I'll try to find the capacitance recommendation of its manufacturer (or ask people that might know), so that you have a basis to decide.
Further I would recommend that - in case you still want to replace the cable+plugs - you use a cable with a capacitance of about 100pF/m and use 1m length of it.
2nd it would be necessary to know how much capacitance is on your phono preamp input (usually stated in the technical details of your pre, usually in the owner's manual).
Then you know how much in total (you just need to add these 2 numbers) you have.
Increasing it is not the problem (if you have switchable capacitance, you can select anyway, otherwise you can just solder in additional capacitance), decreasing is not possible. That's the reason why I recommend 100pF/m and 1m length. Depending on your phono pre this is a solid figure to start.
All the best and have fun with your technics, Hannes
Hi Hannes,
So I did my homework and my preamp is looking for an input of: 2.5mV/47Kohms, but it says nothing about Capacitance. I contacted Rotel directly and they didn't have that info anywhere in their system.
My Cartridge is a Shure M97xE and has the following specs:
Optimum Load 47 kilohms, 200 - 300 picofarads/channel, including tone arm and amplifier input capacitance.
DC resistance 1550 ohms
Inductance 650 millihenries
I found a place online that sells better replacement cables for Technics Turntables for only $20 USD and that is right about what this is worth for an upgrade (59 to 65pF per meter): http://www.kabusa.com/frameset.htm?/index.htm
I will be ordering a meter at the most!
Thanks!
Regards//Keith
So I did my homework and my preamp is looking for an input of: 2.5mV/47Kohms, but it says nothing about Capacitance. I contacted Rotel directly and they didn't have that info anywhere in their system.
My Cartridge is a Shure M97xE and has the following specs:
Optimum Load 47 kilohms, 200 - 300 picofarads/channel, including tone arm and amplifier input capacitance.
DC resistance 1550 ohms
Inductance 650 millihenries
I found a place online that sells better replacement cables for Technics Turntables for only $20 USD and that is right about what this is worth for an upgrade (59 to 65pF per meter): http://www.kabusa.com/frameset.htm?/index.htm
I will be ordering a meter at the most!
Thanks!
Regards//Keith
Hey All,
I called Kevin at KABUSA and he was a great help. If you have any needs for turntables, especially Technics SL-1200/1210 (and other Technics turntables as well) he is the Man! You can also email him, his email is at the web-site in the previous post.
He has very interesting experience and views of the Vinyl world and high end TTs. All of which made you think and see the picture from a better perspective (or at least a different one).
Regards//Keith
I called Kevin at KABUSA and he was a great help. If you have any needs for turntables, especially Technics SL-1200/1210 (and other Technics turntables as well) he is the Man! You can also email him, his email is at the web-site in the previous post.
He has very interesting experience and views of the Vinyl world and high end TTs. All of which made you think and see the picture from a better perspective (or at least a different one).
Regards//Keith
Hi Keith!
Great to hear of your progress!
The Shure is a great choice for sure! It even rhymes ;-)
Just a pity there's no data on the rotel pre!
If you could tell me the exact model no of your Rotel pre, I could have a look.
By the way, ~60pF per meter is a bit on the low side, but of course the lower the better. Increasing it is not the problem. Depending on the Rotel, you will eventually need to add some capacity (easiest to solder an axial pp-cap in the the RCA-plugs to achieve this).
All the best, Hannes
Great to hear of your progress!
The Shure is a great choice for sure! It even rhymes ;-)
Just a pity there's no data on the rotel pre!
If you could tell me the exact model no of your Rotel pre, I could have a look.
By the way, ~60pF per meter is a bit on the low side, but of course the lower the better. Increasing it is not the problem. Depending on the Rotel, you will eventually need to add some capacity (easiest to solder an axial pp-cap in the the RCA-plugs to achieve this).
All the best, Hannes
Hi Hannes,
Thank you for the hand holding and taking such interest! It is so much more productive in the learning cycle than the "One Liner" posts!
The Preamp is a Rotel RTC-850. It is from the early 90s and I guess it isn't high-end enough to publish the desired Phono capacitance. Not much info anywhere about it on Google either.
My next will be a Modwright SWLP 9.0 SE.
BTW I bought the 65 pF/meter cable and 2 meters of it so if I need to make it a little longer, fine, but I'd rather mod the Preamp. I also heard that changing the input impedance resistor from 47K to 75K or 100K is also a benefit! Helps to focus on the music and reduce noise.
Thanks again!
Regards//Keith
Thank you for the hand holding and taking such interest! It is so much more productive in the learning cycle than the "One Liner" posts!
The Preamp is a Rotel RTC-850. It is from the early 90s and I guess it isn't high-end enough to publish the desired Phono capacitance. Not much info anywhere about it on Google either.
My next will be a Modwright SWLP 9.0 SE.
BTW I bought the 65 pF/meter cable and 2 meters of it so if I need to make it a little longer, fine, but I'd rather mod the Preamp. I also heard that changing the input impedance resistor from 47K to 75K or 100K is also a benefit! Helps to focus on the music and reduce noise.
Thanks again!
Regards//Keith
C'mon you're welcome!
I'm happy that I could help you! I'm especially happy that it concerns the capacity topic of MMs which is a topic most people have never heared of. Even hear I read now and then that people build a phono stage (e.g. the pearl) and ask afterwards what they should put into its "Custom capacity" socket. Or if they could leave that out to tune the phono stage (!).
Sorry I haven't been able to locate the needed infos, but if you want to play with the input impedance anyway, you'll have to locate the R_in and C_in and that will solve everything. Maybe best just solder in some sockets.
Let me know, if you want to know something else ;-))
All the best and enjoy your vinyl, Hannes
PS: by increasing the input resistor you also increase thermal noise ;-))
Oh and enjoy your new line stage! Looks gorgeous!
I'm happy that I could help you! I'm especially happy that it concerns the capacity topic of MMs which is a topic most people have never heared of. Even hear I read now and then that people build a phono stage (e.g. the pearl) and ask afterwards what they should put into its "Custom capacity" socket. Or if they could leave that out to tune the phono stage (!).
Sorry I haven't been able to locate the needed infos, but if you want to play with the input impedance anyway, you'll have to locate the R_in and C_in and that will solve everything. Maybe best just solder in some sockets.
Let me know, if you want to know something else ;-))
All the best and enjoy your vinyl, Hannes
PS: by increasing the input resistor you also increase thermal noise ;-))
Oh and enjoy your new line stage! Looks gorgeous!
Hi Hannes,
Thanks for trying to find the info on the Rotel.
Maybe I will try to play with the input capacitance but "I don't need no stinking thermal noise!" So I will stick with the 47K.
I am looking forward to finishing this and listening to Vinyl again!
I am now more educated! Hopefully somewhere along the line, I can return the help!
That Modwright is a beautiful Linestage (plain looking but who cares, it's the sound that is amazing). The only problem is it is expensive, even used. Used goes for at least $2800.00 USD!
What can I sell?
Thanks again for all the help!
Regards//Keith
Thanks for trying to find the info on the Rotel.
Maybe I will try to play with the input capacitance but "I don't need no stinking thermal noise!" So I will stick with the 47K.
I am looking forward to finishing this and listening to Vinyl again!
I am now more educated! Hopefully somewhere along the line, I can return the help!
That Modwright is a beautiful Linestage (plain looking but who cares, it's the sound that is amazing). The only problem is it is expensive, even used. Used goes for at least $2800.00 USD!
What can I sell?
Thanks again for all the help!
Regards//Keith
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