Meissner 9-1065 record cutter

[Markgold55]

Hey everyone. I’m new to the lathe world but would like to get more knowledge and experience. I recently purchased this Meissner 9-1065 record cutter/lathe. I know these are not meant to record high fidelity recordings and that they are very lo-fi. I plan to upgrade in the future but would like to experiment with this one for awhile. The issue I’m having is the audio that is recorded on the record. When I first received the unit no audio would record to the record only noise so I had the cutter head rebuilt by West-Tech. With the rebuilt cutter head I am now able to hear audio on the recorded records but it is very low. The volume needs to be maxed out on my Harman Kardon receiver in order to hear the music at somewhat normal volume. I replaced all of the caps on the unit with exception to the metal can electrolytics and also had all of the tubes tested to make sure they were good. The record player playback works great along with the radio so I’m not sure if the electrolytics could specifically cause an issue with the recording volume or if there is something else I can check to diagnose?

Any help would be much appreciated.

Thanks!

[markrob]

Hi,

If the record player/radio sounds fine, then its not the electronics. The same signal path is used for the cutter head. Might need to go back to Westech. Contact him and let him know and see what he recommends. It is possible that the output transformer is shorted and not developing the proper voltage to the head. Does the "normal" neon lamp light record indicator lamp light when you are cutting? Can you drive it such that the overload neon lights? If so, then the transformer is doing its thing correctly and you are hitting the head with enough level. If not, then you might need to check the output transformer. It's a bit odd as it is configured as a step up auto transformer on the plate side of the circuit. These type heads are very high impedance and need high peak voltage to drive them. If you think the drive levels to the head are ok, then I would look into sending it back.

Ultimately, I would replace the electrolytic's if you plan to use this often. They are old and likely to fail and that might be bad for the power transformer if they short. For now, if there is not excess hum with the unit in player mode with the volume turned down, then they are probably ok. I see this has a choke in the B+ so the caps can be preety bad and the unit will still be pretty low in hum.

The two 10uf cathode bypass caps should be replaced if they are dried out or you will lose quite a bit of gain. They are low voltage and easy to replace with modern caps. To see if they are bad, try lifting one leg of the one on the 6V6 and see if the gain drops by a large amount. If not, then its shot. Same goes for the 6SC7 driver.

Hope that helps.

Mark

[Markgold55]

Thanks Mark,

I did send the cutter head back after it would not work properly but he confirmed the cutter head was good and sent it back to me. He thinks it may be a connection somewhere but was also going to ask about the 4 10mfd bypass caps. The neon lights do light up and if I turn the volume all the way up on my phone(MP3 player) I do see the overload light blink as well but I have noticed when the unit is on for awhile(more than 20 minutes) the lights will go dimmer with no overload when I try to record which produces even lower volume. This was before I replaced the remaining paper wax caps though so I would have to test it again. I cut a record last night with the lights blinking normally and the volume was slightly better but still need to crank the volume all the way up on another player to hear it decently. I only had the unit powered on for 5 minutes or so though. The 10mfd cathode caps that you mentioned are those the 4 bypass caps? If they are responsible for gain should I go ahead and change them out? The record player and radio do work fine though. I wanted to replace them last night but I am not sure which connections are the 4 10mfd bypass caps. I see a total of 6 connections from the bottom of three cans on the chassis but I’m not sure which ones are which. I know 4 of them are the 10mfd caps and 2 of them are the 15mfd caps. I attached a pic with the cans connections circled. I have individual replacement caps to use. I assume the positive end of the new cap would just connect to the wire that is in the can connection and the negative would go to chassis ground?

Thanks,
Mark

[markrob]

Hi,

I can't tell from the photo which 2 caps are the 10uf 25V, but you should be able to figure that out by looking at the cans to see the rating and also tracing the circuit. Given that that radio and record player plays fine, I don't think changing them will make any difference. Also, note that if you decide to replace the cans, you should isolate the connections to the old cans. You don't want them to short down the road. They will still see full voltage and that could cause them to breakdown and short.

If I am understanding correctly, the two level indicator neon bulbs can be made to light on peaks. Since a typical NE-1 fires in the 90V range, I think you are getting the correct drive to the head. The overload lamp is set to fire about 10db higher than the normal indicator (see the voltage divider on the schematic). If you can make both fire, then its probably getting as much signal as the designers intended. If you want more conformation, you could try to connect a digital meter (don't use a low impedance analog meter here) across the head and feed in a steady 1Khz sine wave. Run the gain until the normal neon lights and check the AC voltage. It should read around 64 Vac (.707 * 90V). If you increase the gain and find the point that the overload neon lights, that I calculate should happen at around 190 Vac (64V * 3 due to the voltage divider).

It might be a good idea to cut the 1Khz tone at just below the overload point and see how loud this plays back. Perhaps you are feeding wide bandwidth source material and are eating up power that is not able to be cut. Don't expect this head to make cuts that compete with commercial records. If you have done this and you are still not getting good results, you should contact Westech and explain the testing you have done and see if he can offer any help.

Mark

[Markgold55]

Thanks Mark I really appreciate the help.

The cans are inside the chassis to where I can’t see them only the connections on the bottom of the chassis but I will do my best to trace the circuit. For isolating you mean make sure nothing touches the old connections from the cans that are sticking out if I replace them with individual caps? For the digital meter I would read the AC voltage from the wiring connections from the unit wires and the cutter head while running a 1khz frequency through it right? I attached a pic below. I can remove the wire caps to read the voltage and see what it says.

Thanks,
Mark

[markrob]

Hi,

The metal cans should be stamped with the values on the top of the chassis. If you can't read them, then you will need to trace out the wiring.

Yes, you need to break the connections to the cans. You can use the lugs as tie points and the common ground can stay. It can get a bit messy to do that, but its the best approach. Given how much smaller equivalent caps are today, you can usually find a way. You can follow the wires back to the individual tie points and add the cap locally. This can end up being much neater, but I will warn you that if you do this and ground each cap locally, you can end up with hum problems due to ground loops. Others have removed the cans, cut them open, gutted the innards and added modern replacements. That is really nice looking, but tedious. You can also buy new cans, but they tend to be quite expensive and probably not worth it for this unit. I would avoid NOS as they can be shaky.

The two points you have found would be fine to make the measurement. You could also trace the two wires back to the chassis as well.

Mark

[Markgold55]

Thanks Mark,

The top of the chassis is not visible so I would need to trace the circuit. I’m unable to get to the cans to remove them so would have to replace them underneath with individual caps. For the common ground do you mean the negative end of the new individual caps would need to go to a specific ground point to avoid hum issues? If I do replace them I was planning on just connected ting the negative end of the new caps to the closest chassis ground point. Would this work?

[markrob]

Hi,

You should be able to get to the top of the chassis. Just might require a bit of work to remove the knobs and some screws. Maybe its just too much hassle.

It might work out ok if you add a small axial cap at each circuit point and use the closest ground. You will find out pretty quickly if this results in any ground loop hum issues. Maybe do one at a time and test as you go. If that's the case, you may have to experiment with moving a few of the caps ground point(s) around. In general, there is a star ground point on the chassis where everything returns. All of the cans are clustered in one general area, so all of them are grounded near to each other.

Mark

[Markgold55]

Thanks Mark,

I haven’t done anything with the caps yet but I did try the test that you recommended. I ran a 1khz frequency through the head and measured the ac voltage. I turned the volume dial just to where the normal light is illuminated and I read 93VAC. I turned the volume all the way up to where both the normal and the overload light were illuminated and I got 173VAC. Would this confirm I can leave the caps alone? Also I tried cutting about 10 seconds of the 1khz frequency on a record with the normal light illuminated and the overload light just barely illuminated and the volume was a lot louder. You mentioned something about wide bandwidth audio possibly being the issue. The setup I had was using YouTube on my phone and I also tried with an mp3 from a laptop but in the both cases the cable is going to the headphone jack on the phone/laptop. Same case with cutting the 1khz frequency. Is there a way to get the audio to cut at the same volume as the frequency or to narrow the bandwidth?

Thanks,
Mark

[Markgold55]

Update #2 the frequency that I cut is actually maybe 15% louder after comparing it to a regular commercial 78 but I am seeing the 90VAC and the 173VAC.

Thanks,
Mark

[markrob]

Hi,

Good job testing and measuring the voltages. It seems like you are getting the correct drive to the head. So that's good news. Down the road, I would recommend replacing the caps, but not until you get the loudness issue solved.

I was confused by your second posting. Are you saying that the sine wav test cut is 15% louder than a commercial 78? Or, are you saying that its only 15% louder than your original cuts of program material.

When you cut program material are you able to get the overload neon to flicker? Have you tried really pushing the input recoding level past the overload point to see if there is extra headroom? A bit of overload distortion might not be noticeable and will allow you to increase the volume. Don't be afraid to find out the limits. Other than distortion, you are not going to damage anything.

You can pre-process your audio using an audio app like Audacity to low pass filter the audio and also add some compression and limiting to increase the average loudness. These processes will let you cut somewhat hotter, but depending on you source material may not make a huge difference.

BTW, what material are you cutting? What type of stylus are you using? Other than loudness, is the audio you cut sounding good?

Mark

[Markgold55]

Thanks Mark,

Yes the cut with the frequency was only around 15% louder than the audio that I have been recording. Not near as loud as a commercial record. When I connect the phone to the mic input and set it to either “record mic” or “record radio” I am able to see the overload light flicker if I turn the recording volume all the way up. I usually use the record radio option that way I can hear the source material from the speaker even though it is also low but I have tried both. I have been cutting to where the overload light is just barely blinking. If I turn it all the way up the music sounds very distorted coming from the speaker but I can try and cut like that to see how it sounds on the record. I’m using pvc discs that I purchased from recordblanks.com but I also have a few coated original metal acetates that came with the unit. Those seem to be less noisy but both have the same volume. I’m using a sapphire cutting stylus that came with the unit but I also purchased a steel cutting stylus from Gib at West Tech. Both cut with the same volume but the sapphire cuts with less noise. Wish I can attach a video here. The audio sounds decent as long as the volume is maxed out. Very little bass/treble presence but I’m sure that’s tied to the volume as well. I do have audacity but I haven’t messed with any of the editing settings yet. Good to know though if I’m getting the correct voltages to the head it shouldn’t have anything to do with the electrolytic bypass caps. Could it possibly be the cutting head. Gib did confirm it was good though. He had me do a test where I use the cutting head and hook it up to the playback arm and play a record with a regular stylus to see how loud it was and it did play the record loud.

Thanks,
Mark

Thanks,
Mark

[markrob]

Hi Mark,

Sorry about the delay responding. I've never owned one of these machines, so I can't really comment on how loud they were able to cut. I suspect that you may be up against the limits of what the head can do. Its unlikely that there are any original heads in working condition to compare against. It would be good to get a quantitative number on how much lower in level your cut is as compared with a commercial cut. To do that, you would need to capture a commercial cut to a file and then without changing any playback settings, capture your cut to a file. The use some software to measure the the average loudness of each cut (I think Audacity can do this). The dB difference between the two captures will give you a good number to use. I'm not sure what to expect, but I would guess the difference could be as much as 10dB. You could post the samples here and maybe some of the owners here can comment on the results.

You could try to talk with Gib at Westech to see if there is anything he can do to boost the response of his re-build, but I suspect there is not much to be done. Astatic did make a magnetic replacement cutter head for these units, but they are rare to find and I'm not sure how much better they are.

ark

[Markgold55]

Thanks Mark,

No worries I really appreciate the help. I will try to cut and record a sample to upload in Audacity and compare it to the source audio. I would say the cuts are about 1/8 the volume of a commercial record.

Thanks,
Mark

[ZephyrRadio]

IDK if there's already one of these available... if yes, here's another. (If not, here's one?) I bought and scanned this looking for more information about the GI-R-90 turntable they used.