Help with a BSR/McDonald LS-1 TT.....

[wal92tt]

I recently bought this on CL for $25 and I was told the guys father used it for a bit when new but it sat boxed up ever since. It looks like new to me. I had to use a soldering iron to remove the platter and gear in order to clean it and oil it. It all looks good and clean but when I play records, it plays at an extreme volume and gets louder as the music gets louder, regardless of how low I turn the volume. I've tried a new needle and still the same. I bought this just to play 78's that I've collected but never have listened to.
Is there something I'm missing? My regular TT is a Pioneer PL-55 and sounds great. My Yamaha CR-2020 needs servicing so I'm using an 80's Marantz TA 100 which is ugly buts sounds great in the mean time. The BSR does not have a ground wire in case that makes any difference? I have not been able to find any info on this TT by the way.
Thank you in advance, Wally

 

[tubewade]

Likely it has a ceramic cartridge. This was intended to be used into a high impedance line level input and not a magnetic input. If this is the case, put a 1k ohm resistor across each lead from the cartridge to common/ground, underneath the table, and then you will be able to connect it to your magnetic phono input.

 

[noogies]

... or just plug it into an unboosted line level input ...

 

[tubewade]

... or just plug it into an unboosted line level input ...

You can do this, but the high impedance ceramic cartridge likes to see about 1M ohm or higher input impedance at line level, otherwise all the bass does a disappearing act. Transistor and IC amplifiers often have line level input impedance of around 50k ohms.

 

[Bill Beausol]

Nope, you can't connect to the phono input because in addition to the gain, the phono circuit is equalized with the RIAA curve and ceramic cartridges have a frequency response that mimics the curve without equalization. i.e. Ceramic cartridges fall off on the high end in approximately the way the RIAA curve requires without equilization. Use a line level input.

 

[noogies]

Well, it looks like we're stymied until OP lets us know whether it's a magnetic or ceramic cartridge. BSR used both. I'm not familiar with the model so I Googled it but came up empty.

 

[tubewade]

Nope, you can't connect to the phono input because in addition to the gain, the phono circuit is equalized with the RIAA curve and ceramic cartridges have a frequency response that mimics the curve without equalization. i.e. Ceramic cartridges fall off on the high end in approximately the way the RIAA curve requires without equilization. Use a line level input.

This is absolutely true. A ceramic cartridges output is based on amplitude, which when loaded with a high impedance, approximates the RIAA curve. Loading the high impedance device with a low impedance, the 1k ohm resistor in my first suggestion, will turn its output to velocity based, allowing one to plug it into a magnetic input and get actual RIAA equalisation in the preamp. Alternatively you can use a 100pF capacitor in series with each cartridge output lead and achieve the same thing. Try it! It really does work. If you look inside many solid state preamps that have ceramic phono inputs you'll see they have done the same thing.

 

[tubewade]

I've found much the same thing, Joseph. And found that using a 1k load will pull the output down as needed even more than the standard 47k load in a phono input you are using, thereby eliminating the need (or requirement) for gain adjustment. And I agree that some ceramics can sound very nice when the conditions are right. I've done the same thing we are talking about with the EV and Astatic ceramics in my Collaro changers.

 

[noogies]

If the OP has been reading along, he may be having second thoughts.

 

[tubewade]

I agree about optimising as much as one is able and having a little dedication. I hope no one would feel overwhelmed in this case by needing to add a resistor or two or a small capacitor outside the amplifier. On a BSR the leads from the pickup are available at the RCA socket under the platter. I would encourage him or anyone else, don't give up. It's not that difficult.

noogies suggestion to plug into a line level input will verify whether it is a ceramic cartridge. If plugged in to the AUX input and the level seems "normal" (probably slightly lower than a tape or radio) and relatively undistorted then he will have to decide if that sound is acceptable or if it would be worth the effort to try to improve it a bit. If the level is so low that he has to turn the volume up all the way to hear it then it is a magnetic and we can try to sort those problems.

 

[noogies]

Bottom line, we need input from OP before proceeding to solve his problem for him and he hasn't been heard from since Wednesday, so he may indeed have been scared straight.

 

[wal92tt]

All this is over my head. Here are some pics if they may help? The cartridge is not removable. I'm assuming this was part of a stereo system which is why there's literally nothing online about it? If you're expecting me to operate on this, I literally need step by step instructions in bafoon English. I'm pretty sure my Yamaha has both phono inputs for mm and ceramic but it's not working for now....
Thank you for all the responses, but apparently none of them were emailed to me and I just now found them Googling for info on it again.

 

[cardnut]

I have a BSR McDonald 50MX TT that I am having issues trying to find any manuals or info on.

IMG_0351

• cardnut
• Jul 12, 2019

product tag

IMG_0350

• cardnut
• Jul 12, 2019

BSR McDonald 50MX

Any help would be appreciated.