Balles kladdebok

[Balle Clorin]

Noe nytt gammelt på vei...impulskjøp..

 

[Sevald]

For å finne ut hva compliance /resonans er på en pickup må man vite hva effektiv masse på sin tonearm er, og hva den er med pickup montert. Vanligvis tar man den oppgitte effektive massen og legger til pickup vekten. Men effektiv masse er ikke bare effektiv masse, Er oppgitt effektiv masse med armen balansert med eller uten pickup vil det utgjøre en forskjell. Så for å nerde litt om dette lekte jeg meg med litt matematikk og statikk og moment.

Det viser seg at legger man til masse til en balansert arm må jo armen rebalanseres og det medfører endring=ØKNING av den effektive massen, og etter mye knot og sjekk og noen feil og til slutt korrigering av feilen kommer jeg fram til følgende formel:

dEM= Økning i effektiv masse=CM1+(CM1^2+2*H*CM1)/W

Hvor:

CM1=PU masse eventuelt annen endring av vekt

H= Effektiv masse av headshell enden av armen, typisk 90 til 95 % av oppgitt effektiv masse

W= Masse av motvekt

La oss ta et eksempel med oppgitt effekt masse 10 gram og legge til pickup på 10 g med skruer og det hele, og en motvekt på tohundre gram (som er ganske heftig=high end motvekt)

dEM=10+(10*10+2*(10*0.95)*10)/200=10+1.45=11.45 gram

Ny effektiv masse er dermed ikke 10+10=20 men 10+10+1.45=21.45 gram eller hele 3.6% lavere resonans frekvens, (eventuelt samme % effekt på beregnet compliance fra testplate resonans Hz). Har man lettere motvekt for eksempel 100gram blir tillegget dobbelt så mye, nesten 3 gram. Dette kan jo være en forklaring for de som lurer på hvorfor resonanfrekvensen ble lavere enn de trodde…

Det er jaggu mye å bekymre seg for angående vinyl reproduksjon

Spoiler: utleding og sjekk med rettelser

Vis vedlegget 1127692

Dette regner ChatGPT ut på 2 sekunder….

 

[Balle Clorin]

Dette regner ChatGPT ut på 2 sekunder….

Slett ikke, jeg sjekket også med AI og spurte Microsoft sin AI og den regnet feil 3 ganger som vanlig, etter å ha irettesatt ai noen ganger fikk den det til..
Første gale svar var feks at 8 gram PU øker effektiv mass med 8g, deretter regnet den ute feil effektiv masse og måtte så korrigeres en gang til..
ta en titt her..

Linn Lp-12

Slapp av, dette ser helt riktig ut. Ingen grunn til å bytte plata pga. den svaien der. Når plata bøyes i den andre retningen, som ptb skriver over, blir det en bøy som den du har på høyre side. Venstre side rettes ut, det må den for å få god kontakt med konsollen i plinthet, men bøyen på høyre...

www.hifisentralen.no

Har ikke ChatGPT, mulig den er smarere enn Microsoft CoPilot
Har ikke turt å bruke chat GPT, enda en brukerpofil som melkes for data, men den er kansje verdt det om den regner riktig

ny test
can you provide a formula for calulating the incread in effective mass when adding a cartridge to a turntable tonearm with knoen effective mass.

Of course! Let’s keep it simple and clear.


To calculate the total effective mass when you add a cartridge to your tonearm, just use this plain formula:


Total Effective Mass = Tonearm Mass + Cartridge Mass + Mounting Hardware Mass


Here’s how each part breaks down:

• Tonearm Mass is what the manufacturer lists as the effective mass of your tonearm (in grams).
• Cartridge Mass is the weight of the cartridge you’re adding.
• Mounting Hardware Mass includes the screws and any small pieces used to attach the cartridge—usually about 0.5 to 1 gram.

So, for example:

• If your tonearm has an effective mass of 11 grams
• Your cartridge weighs 6 grams
• And your mounting hardware is 1 gram

Then the total effective mass = 11 + 6 + 1 = 18 grams


Let me know what values you're working with, and I can run the numbers for you!
Or if you want help choosing a good cartridge match, I’ve got you covered.


this is not the correct answer, when adding a pickup to an arm the arm must be relabalances and thet changes the effective mass, it increases the total effecrive mass more then the added cartridge mass

You're absolutely right, —and that’s a crucial nuance in tonearm physics that gets missed too often in simplified explanations.


When you add a cartridge (pickup) to the end of the tonearm and then rebalance the arm using the counterweight, you're not just adding mass—you’re redistributing it. The act of balancing introduces a torque-dependent dynamic that increases the moment of inertia of the entire moving system, which effectively raises the moving mass more than the sum of its parts.


To more accurately reflect this, we consider the effective mass as being related to how mass is distributed along the tonearm's length and how it affects the stylus during groove modulation. That’s why two tonearms with the same physical mass can behave differently depending on that mass distribution.


A more precise calculation would involve modeling the arm as a lever, using rotational inertia principles. That’s not always practical outside a lab—but for enthusiasts or tonearm designers, it’s not uncommon to use:


Effective Mass ≈ physical mass of all components × (distance from pivot to center of mass)²


If you’re balancing with a heavier cartridge, the counterweight must shift farther back to achieve equilibrium—that increases the radius of mass distribution, and thus, the effective mass rises more than linearly.


Would you like a more detailed walkthrough of that principle? Or maybe a way to estimate the effect without needing a physics lab in your living room?

.og så fortsetter den med feil svar noen ganger til

 

[Sevald]

Slett ikke, jeg sjekket også med AI og spurte Microsoft sin AI og den regnet feil 3 ganger som vanlig, etter å ha irettesatt ai noen ganger fikk den det til..
Første gale svar var feks at 8 gram PU øker effektiv mass med 8g, deretter regnet den ute feil effektiv masse og måtte så korrigeres en gang til..
ta en titt her..

Linn Lp-12

Slapp av, dette ser helt riktig ut. Ingen grunn til å bytte plata pga. den svaien der. Når plata bøyes i den andre retningen, som ptb skriver over, blir det en bøy som den du har på høyre side. Venstre side rettes ut, det må den for å få god kontakt med konsollen i plinthet, men bøyen på høyre...

www.hifisentralen.no

Har ikke ChatGPT, mulig den er smarere enn Microsoft CoPilot
Har ikke turt å bruke chat GPT, enda en brukerpofil som melkes for data, men den er kansje verdt det om den regner riktig

Mulig. Fikk dette svaret når jeg sjekket:

 

[Balle Clorin]

Mulig. Fikk dette svaret når jeg sjekket:

Vis vedlegget 1127962 Vis vedlegget 1127963

Poenget er et den effektive massen til armen din IKKE er konstant den er ikke 12 gram lengre, den er ØKT fordi du må flyte motvekten litt lengre bak når du legger på vekt i pickup enden, og det endrer den effektive masse. Eller sagt på en annen måte den reelle effektive massen til armen er en funksjon av posisjon av motvekten, Kanskj derfor SME V oppgit til 10/11 gram

Det burde vært en standard som oppgir den effektive massen til armen med en gitt PU vekt, og en gitt VTF for en statisk balanser arm.
Men feilen er ikke stor da, 5-10%

 

[Sevald]

Poenget er et den effektive massen til armen din IKKE er konstant den er ikke 12 gram lengre, den er ØKT fordi du må flyte motvekten litt lengre bak når du legger på vekt i pickup enden, og det endrer den effektive masse. Eller sagt på en annen måte den reell effektive massen til armen er en funksjon av posisjon av motvekten

Det burde vært en standard som oppgir den effektive massen til armen med en gitt PU vekt, og en gitt VTF for en statisk balanser arm.
Men feilen er ikke stor da, 5-10%

Med 5-10% avvik så er jeg fremdeles innafor

 

[Balle Clorin]

Jeg er lavere 8-9hz, da betyr et avviket mer.
God natt

 

[Balle Clorin]

Fisher MT-6330 Turntable inside pictures:

OK, litt på impuls plukket jeg opp denne Fisher MT- 6330 for noen hundrelapper , den er ment å erstatte Sony PS-212 som kjøkkenbenk/pickupsjekker.
Med original AT-10 OEM pickup. Plastikkspiller men med flytende internt chassis

Gjenskinnet gjør det vanskelig å ta bilde av coveret..
Hastigheten er OK stabil på 33rpm, mer kilen på 45, så det er nok rom for forbedring ved å sjekke og justere manuelt iht servicemanualen.

Det er fortsatt bedre enn mye annet som fås kjøpt nytt i dag.

Variasjon på 0.1% per rotasjon tilsvarer faktisk 0.032% DIN W&F.
Faktisk nær spec på 0.035% 45 år gammel er ikke ille.

Innmat

Fix tips that might become useful.
Fisher Studio Standard Turntable TOO FAST - Page 2 - Antique Radio Forums


Tweaks og forbedringer...

This system has a 24V unregulated power supply, in order to make a better system can I replace the existing supply with a stabilized 24V LM317 regulator based on a switch mode power supply

Yes, you can replace the unregulated 24 V supply with a regulated one to improve system performance. Using a stabilized 24 V supply means that all the biasing, oscillator operation, and servo control functions see a steady voltage without ripple or drift. That helps improve overall stability and may reduce unwanted noise in the control loop.
A common approach is to combine the efficiency of a switch-mode power supply (SMPS) with the precision of a linear regulator. For example, you could build an SMPS that outputs, say, 28–30 V and then use an LM317 (or a better low-dropout option, if needed) to drop and regulate that down to exactly 24 V. This hybrid approach has several advantages:

1. Improved Efficiency and Reduced Heat: The SMPS stage handles the bulk conversion efficiently, avoiding the excess heat that a purely linear regulator would generate with a high voltage drop. This is particularly beneficial when there’s a significant difference between the raw supply voltage and your desired 24 V level [2].
2. Stable, Clean Output: The LM317 (or similar adjustable linear regulator) further cleans up the voltage by providing excellent regulation and low ripple. A stabilized 24 V rail is far superior for sensitive analog circuits, such as the oscillator and servo circuits in your MT‑6330, compared to an unregulated supply that might vary with load and time.
3. Better Servo and Oscillator Performance: With a fixed and predictable supply, the oscillator’s operating points and bias conditions remain constant. This helps maintain accurate modulation and servo control for the motor. Fluctuations in an unregulated supply could otherwise cause small shifts in bias, leading to performance inconsistencies.
4. Design Considerations:
   • Dropout Requirements: Keep in mind that the LM317 typically has a dropout voltage of around 2 V. Thus, your pre-regulator or SMPS stage should supply a voltage high enough (typically 26–28 V for a desired 24 V output) to allow the LM317 to regulate properly.
   • Noise and Filtering: While SMPS can sometimes introduce switching noise, proper filtering (using output capacitors and possibly additional LC filtering) will ensure that the regulated 24 V rail is as quiet as required for high-performance audio or motor control applications.
   • Current Requirements: Make sure the LM317 and the associated switching regulator can supply the needed current for your system. Although the LM317 is versatile, in higher-current applications you might consider a different regulator with a lower dropout and better thermal performance.

This approach is popular in projects where efficiency and stability are paramount. Several hobbyists and professionals have adopted similar methods to replace older unregulated power supplies with a combination of SMPS and linear regulation for improved performance [2][3].
Would you like to explore a potential schematic or simulation setup in LTspice to see how this can be implemented or discuss further refinements in the design?

Thanks, can you suggest a better regulator than LM317 in this service
Based on experiences shared by audio DIY enthusiasts and experts, there are a few options that tend to outperform the LM317 in terms of noise, dropout voltage, and overall stability. One popular alternative is the LT1963 series. Here’s why it might be a better choice:

1. Lower Noise and Better PSRR: The LT1963 is designed to have lower output noise and better power-supply rejection, which is especially important in high-performance audio and servo control circuits. The cleaner regulation can result in fewer unwanted disturbances in your servo loop.
2. Low Dropout Operation: Compared to the LM317, the LT1963 has a lower dropout voltage, meaning it can maintain regulation with a smaller difference between the input and output voltages. In an application where efficiency and tight voltage regulation are critical, this feature is very beneficial.
3. Performance Under Load: The LT1963 (or similar parts like the LT1084, if you require higher current capacity) typically handles transient load changes more gracefully than the LM317. This means a more stable output, which is key for applications requiring smooth and reliable control signals, such as in the turntable’s servo control system.
4. Pin Compatibility and Ease of Integration: In many cases, regulators like the LT1963 are available in pin-compatible packages, making them relatively straightforward substitutes for the LM317 in your design. This allows you to benefit from enhanced performance without a complete redesign of your board layout.

For your application in refining the servo control in the MT‑6330, using a regulator with improved noise characteristics and tighter voltage regulation can contribute to a more stable and predictable performance. Other options—like the LM338 or LT1084—also offer improvements and should be selected based on your specific current and thermal requirements.
Would you like to see a sample LTspice simulation incorporating the LT1963 (or another alternative) for a side-by-side comparison with the LM317, or additional details on its power characteristics in a servo-controlled design?

Baser på dette kan man regne med at MT-6225 har bedre elektonikk motor styring enn MT- 6330 ( regulert spenning og oscillator referert til 0 jord) . men at 6330 har bedre isolering og er mindre sensitiv mot omgivelser pga flytende oppheng.
6250 blir enda ett hakk opp med Quartz oscillator

Spoiler: Modifikasjon

For the LT1963, you'll generally want to provide a bit more than 24 V at the input—usually around 25 V—to ensure adequate headroom for regulation. Here’s why:

1. **Dropout Voltage Consideration:**
The LT1963 is a low dropout regulator, but it still typically requires around 300–400 mV of headroom under moderate to heavy load conditions. This means that even though its dropout is low compared to older regulators like the LM317, you still need the input to be higher than your desired output. In a light-load scenario the dropout can be lower, but for worst-case operation and to account for ripple or component tolerances, having about a 1 V margin is a good rule of thumb.

2. **Practical Recommendation:**
With a 24 V output target, boosting the input to roughly 25 V ensures that under all operating conditions the regulator has enough “extra” voltage to work with. This margin helps improve line regulation and ensures that transient dips in the supply (or demands from the load) won’t cause the output voltage to drop out of specification.

3. **Additional Factors:**
If your pre-regulated or switch-mode power supply output isn’t perfectly steady (i.e., if it has any significant ripple or transient spikes), the additional headroom provided by a 25 V input can help maintain a stable and clean 24 V output.

So, while the LT1963 is very efficient at maintaining output close to the input under light loads, a practical input voltage of about **25 V** is recommended to comfortably achieve a stable 24 V output.

Would you like to explore how this might be modeled in a transient or AC simulation in LTspice, or discuss how the actual load current affects the dropout voltage further?


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AC TO DC Adjustable Adapter Source High Voltage Transformer 3V 5V 12V 24V 36V 2A 3A 5A 10A DC Female Alligator Clip Connector - AliExpress

 

[Balle Clorin]

Denon 51F er fortsatt best

 

[Balle Clorin]

Fisher MT-6330 Turntable inside pictures:

OK, litt på impuls plukket jeg opp denne Fisher MT- 6330 for noen hundrelapper , den er ment å erstatte Sony PS-212 som kjøkkenbenk/pickupsjekker.
Med original AT-10 OEM pickup. Plastikkspiller men med flytende internt chassis

Vis vedlegget 1128026
Vis vedlegget 1128028
Vis vedlegget 1128030
Gjenskinnet gjør det vanskelig å ta bilde av coveret..
Hastigheten er OK stabil på 33rpm, mer kilen på 45, så det er nok rom for forbedring ved å sjekke og justere manuelt iht servicemanualen.

Det er fortsatt bedre enn mye annet som fås kjøpt nytt i dag.
Vis vedlegget 1128033

Vis vedlegget 1128294




Variasjon på 0.1% per rotasjon tilsvarer faktisk 0.032% DIN W&F.
Faktisk nær spec på 0.035% 45 år gammel er ikke ille.

Innmat
Vis vedlegget 1128042
Vis vedlegget 1128043
Vis vedlegget 1128044
Vis vedlegget 1128045

Vis vedlegget 1128266 Vis vedlegget 1128267

Fix tips that might become useful.
Fisher Studio Standard Turntable TOO FAST - Page 2 - Antique Radio Forums


Tweaks og forbedringer...

This system has a 24V unregulated power supply, in order to make a better system can I replace the existing supply with a stabilized 24V LM317 regulator based on a switch mode power supply

Vis vedlegget 1128676


Yes, you can replace the unregulated 24 V supply with a regulated one to improve system performance. Using a stabilized 24 V supply means that all the biasing, oscillator operation, and servo control functions see a steady voltage without ripple or drift. That helps improve overall stability and may reduce unwanted noise in the control loop.
A common approach is to combine the efficiency of a switch-mode power supply (SMPS) with the precision of a linear regulator. For example, you could build an SMPS that outputs, say, 28–30 V and then use an LM317 (or a better low-dropout option, if needed) to drop and regulate that down to exactly 24 V. This hybrid approach has several advantages:

1. Improved Efficiency and Reduced Heat: The SMPS stage handles the bulk conversion efficiently, avoiding the excess heat that a purely linear regulator would generate with a high voltage drop. This is particularly beneficial when there’s a significant difference between the raw supply voltage and your desired 24 V level [2].
2. Stable, Clean Output: The LM317 (or similar adjustable linear regulator) further cleans up the voltage by providing excellent regulation and low ripple. A stabilized 24 V rail is far superior for sensitive analog circuits, such as the oscillator and servo circuits in your MT‑6330, compared to an unregulated supply that might vary with load and time.
3. Better Servo and Oscillator Performance: With a fixed and predictable supply, the oscillator’s operating points and bias conditions remain constant. This helps maintain accurate modulation and servo control for the motor. Fluctuations in an unregulated supply could otherwise cause small shifts in bias, leading to performance inconsistencies.
4. Design Considerations:
   • Dropout Requirements: Keep in mind that the LM317 typically has a dropout voltage of around 2 V. Thus, your pre-regulator or SMPS stage should supply a voltage high enough (typically 26–28 V for a desired 24 V output) to allow the LM317 to regulate properly.
   • Noise and Filtering: While SMPS can sometimes introduce switching noise, proper filtering (using output capacitors and possibly additional LC filtering) will ensure that the regulated 24 V rail is as quiet as required for high-performance audio or motor control applications.
   • Current Requirements: Make sure the LM317 and the associated switching regulator can supply the needed current for your system. Although the LM317 is versatile, in higher-current applications you might consider a different regulator with a lower dropout and better thermal performance.

This approach is popular in projects where efficiency and stability are paramount. Several hobbyists and professionals have adopted similar methods to replace older unregulated power supplies with a combination of SMPS and linear regulation for improved performance [2][3].
Would you like to explore a potential schematic or simulation setup in LTspice to see how this can be implemented or discuss further refinements in the design?

Thanks, can you suggest a better regulator than LM317 in this service
Based on experiences shared by audio DIY enthusiasts and experts, there are a few options that tend to outperform the LM317 in terms of noise, dropout voltage, and overall stability. One popular alternative is the LT1963 series. Here’s why it might be a better choice:

1. Lower Noise and Better PSRR: The LT1963 is designed to have lower output noise and better power-supply rejection, which is especially important in high-performance audio and servo control circuits. The cleaner regulation can result in fewer unwanted disturbances in your servo loop.
2. Low Dropout Operation: Compared to the LM317, the LT1963 has a lower dropout voltage, meaning it can maintain regulation with a smaller difference between the input and output voltages. In an application where efficiency and tight voltage regulation are critical, this feature is very beneficial.
3. Performance Under Load: The LT1963 (or similar parts like the LT1084, if you require higher current capacity) typically handles transient load changes more gracefully than the LM317. This means a more stable output, which is key for applications requiring smooth and reliable control signals, such as in the turntable’s servo control system.
4. Pin Compatibility and Ease of Integration: In many cases, regulators like the LT1963 are available in pin-compatible packages, making them relatively straightforward substitutes for the LM317 in your design. This allows you to benefit from enhanced performance without a complete redesign of your board layout.

For your application in refining the servo control in the MT‑6330, using a regulator with improved noise characteristics and tighter voltage regulation can contribute to a more stable and predictable performance. Other options—like the LM338 or LT1084—also offer improvements and should be selected based on your specific current and thermal requirements.
Would you like to see a sample LTspice simulation incorporating the LT1963 (or another alternative) for a side-by-side comparison with the LM317, or additional details on its power characteristics in a servo-controlled design?

Baser på dette kan man regne med at MT-6225 har bedre elektonikk motor styring enn MT- 6330 ( regulert spenning og oscillator referert til 0 jord) . men at 6330 har bedre isolering og er mindre sensitiv mot omgivelser pga flytende oppheng.
6250 blir enda ett hakk opp med Quartz oscillator

Spoiler: Modifikasjon

Vis vedlegget 1128684

For the LT1963, you'll generally want to provide a bit more than 24 V at the input—usually around 25 V—to ensure adequate headroom for regulation. Here’s why:

1. **Dropout Voltage Consideration:**
The LT1963 is a low dropout regulator, but it still typically requires around 300–400 mV of headroom under moderate to heavy load conditions. This means that even though its dropout is low compared to older regulators like the LM317, you still need the input to be higher than your desired output. In a light-load scenario the dropout can be lower, but for worst-case operation and to account for ripple or component tolerances, having about a 1 V margin is a good rule of thumb.

2. **Practical Recommendation:**
With a 24 V output target, boosting the input to roughly 25 V ensures that under all operating conditions the regulator has enough “extra” voltage to work with. This margin helps improve line regulation and ensures that transient dips in the supply (or demands from the load) won’t cause the output voltage to drop out of specification.

3. **Additional Factors:**
If your pre-regulated or switch-mode power supply output isn’t perfectly steady (i.e., if it has any significant ripple or transient spikes), the additional headroom provided by a 25 V input can help maintain a stable and clean 24 V output.

So, while the LT1963 is very efficient at maintaining output close to the input under light loads, a practical input voltage of about **25 V** is recommended to comfortably achieve a stable 24 V output.

Would you like to explore how this might be modeled in a transient or AC simulation in LTspice, or discuss how the actual load current affects the dropout voltage further?


Wall Mount Power Supply 30v 32v 33v 500ma 1a 2a Ac Dc Adapter - Buy 30v Ac Dc Adapter 30v 1a Ac Dc Adapter 32v Ac Dc Adapter Product on Alibaba.com


AC TO DC Adjustable Adapter Source High Voltage Transformer 3V 5V 12V 24V 36V 2A 3A 5A 10A DC Female Alligator Clip Connector - AliExpress

Dermed er en fersk pickup montert og satt opp... Armen er mye bedre enn på Sony Ps -212 og platetallerken er bedfe på Fisher også, tydelig mindre rusk og resonanser under 1000hz. kansje 16 gram effektiv masse +3 gram skruer hjelper
VTA er nok ikke helt optimal ennå,får se på det senere

 

[Balle Clorin]

Wally skater med litt tilpasning…

 

[Balle Clorin]

Da er den nye strømforsyningen til Fisher spilleren ankommet. Meningen er å koble fra trafoen og forsyne de spesifiserte 24V DC til det riktige interne punktet ( etter likeretter)
Blir spennende å se hvilken effekt det gir å få en regulert DC spenning i stedet for bare likeretting og kondensator glatting. Blir også kvitt trafo støy og trafo-vibrasjoner.
Her en kort test på 58watt, spec er 60 Max . Stabil spenning i allefall. Spilleren trenger under 10 watt faktisk bare 2.2W i følge bakplaten , så kapasiteten er grei. Kanskje man bør spe på med litt dummy last???

På 10watt last.

11euro og noen smådeler totalt 200kr med frakt og moms.

Spoiler: Dummy load

Impact of Low Load on a 3–35 VDC, 60 W Switch-Mode Supply
Using a switch-mode bench supply at just 2.2 W (≈ 90 mA at 24 V) can sit below its built-in minimum‐load threshold. Many off-the-shelf 3–35 VDC, 60 W modules specify a minimum load of 5–10 % of full rated current—at 60 W/24 V that’s 2.5 A, so 10 % is 250 mA. Below this they often:

• Drop out of regulation
• Overshoot or wander in output voltage
• Exhibit higher ripple and noise
• Enter intermittent “hiccup” mode

• Switch-mode regulators sense current through their feedback network.
• At very light loads they can’t maintain stable feedback, so duty cycles mis‐fire.
• Resulting voltage can float above your setpoint or oscillate.

Draw at least the minimum operating current. For 250 mA at 24 V:
R = V/I = 24 V / 0.25 A ≈ 96 Ω
P = V·I = 24 V·0.25 A = 6 W
Use a 100 Ω, 10 W metal-film resistor across the output. That ensures ~240 mA dummy current. Total load becomes ≈ 330 mA.

• Mount the resistor outside the chassis or on a heatsink inside.
• Verify speed stability with a strobe disc after adding the dummy load.
• If noise persists, place a small inductor (≈ 100 µH) in series and a 100 µF low-ESR cap at the motor feed.

How the LC Filter Works
An LC filter on your DC output combines a series inductor and a bypass capacitor at the motor terminals to tame high-frequency switching noise and smooth current surges.

Series Inductor (≈ 100 µH)

• Placed in the positive lead between the supply and the motor.
• Opposes rapid changes in current, blocking high-frequency spikes.
• Choose an inductor rated above your motor’s steady current (e.g., ≥ 0.5 A).
• Ferrite-core chokes or powder-core inductors work well for 20–100 µH.

Bypass Capacitor (100 µF, Low-ESR)

• Connected from motor “+” to “–” (ground) as close to the motor terminals as possible.
• Provides a local charge reservoir to absorb voltage ripple.
• Low equivalent series resistance (ESR) ensures it handles fast transients.
• You can parallel a small ceramic cap (e.g., 0.1 µF) to catch very high frequencies.

Wiring and Layout

1. Cut the positive lead between your power supply and the motor.
2. Solder the inductor inline on that lead.
3. Right at the motor end, connect the 100 µF cap between the positive rail and ground.

• Keep leads short (< 5 cm) to minimize added inductance or loop area.
• Secure components so vibration from the turntable won’t loosen them.
• If noise still shows up on a scope, add a small RC snubber (e.g., 100 Ω + 100 nF) across the motor.
• Twisting power leads together reduces radiated EMI.
• A common-mode choke on both + and – can further suppress emissions.
• Always re-check speed stability with your strobe after each change.

link

Using Adjustable Power Supply for Turntable

Delt via Copilot

copilot.microsoft.com

Using Adjustable Power Supply for Turntable

Delt via Copilot

copilot.microsoft.com

Ok, I use a metal box then, the turntable and RIAA only have 2-prong contact

Delt via Copilot

copilot.microsoft.com

## Single‐Point Grounding Inside Your Filter Box

You want exactly one solid bond between your 0 V “minus” rail and the metal chassis—at the SMPS inlet. All other minus connections (bleeder resistor, capacitors, output minus) tie to that same internal bus, but nowhere else.

---

### 1. Inlet Bond (Your Only Chassis Tie)

- Bring the SMPS “–24 V” lead into the box.
- Directly at that feed-in point, crimp/solder it to a ring lug and bolt that lug to the chassis wall.
- This is your sole chassis‐to‐minus connection.

---

### 2. Internal Minus Bus

- From the inlet lug, run a short, fat jumper to a small terminal strip or buss bar.
- Land all internal negatives here:
- Bleeder resistor
- Electrolytic bulk cap “–”
- Ceramic bypass cap “–”
- Output minus conductor

---

### 3. Output Feed-Through

- Use an **insulated** feed-through or plastic-bushed terminal for the box’s “– 24 V” exit.
- The minus wire to your turntable ties to this insulated terminal—**it must not** again touch chassis.
- Your box’s chassis remains isolated from that output pin except via the single inlet bond.

---

### 4. Why Not Tie Minus at the Outlet?

- A second chassis tie creates a ground loop: two parallel return paths (inlet & outlet) can encourage hum or RF coupling.
- Keeping the outlet minus insulated ensures all ground currents flow through your one designed star point.

---

### 5. Quick Layout Sketch

```text
SMPS –24 V In ──┬──– Lug bolted to Chassis ← SINGLE bond
│
+── Internal Minus Bus (terminal strip)
│ │ │
[Bleeder] [Cb] [Output – (insulated)]
│ │ │
SMPS +24 V In ── L ─────+── Bulk cap +── Output +24 V
```

- L = series choke
- Cb = bypass cap

All “–” legs join at the terminal strip, but only the inlet lug touches chassis steel. The exit minus lead runs on its own insulated post.

---

### 6. Cable Shielding on Output

- On your +/– pair to the turntable, carry a third (shield) conductor.
- Terminate the shield to chassis **only** at the filter‐box side.
- Leave it floating or tied to the turntable’s own chassis at the other end—never bond both ends to box.

Following this single‐bond, insulated‐output scheme gives you the cleanest return path and avoids ground‐loop noise while keeping your 0 V rail tied solidly to the enclosure.