KA-electronics Flat phono MC preamp.
- Trådstarter habicht
- Startdato
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Hvis det er snakk om et gruppekjøp hiver jeg meg gjerne med på et kjøp.
gruppekjøpet skjedde i fjor, men PSU løsningen har ventet på seg siden silentswitcherene aldri kom tilbake på lager - vi skal vel til å bestille noen forsyninger som wayne hadde på lager, så om han har noen MC kort klare for levering går det kanskje an å slenge seg på bestillingen.
@habicht
Bra habicht
Da er det bare å glede seg.
Wayne skal også ordne en koblingsskjema for tilkobling av 2 armer med separat last innstilling.
Han skulle bare gjøre klar en bestilling først
Han sender med ups til Jet carrier så dette bør gå relativt fort.
I received your payment, thank you!
I'll put the FMCP preamps on an overnight burn-in and do a pre-shipment QC on them tomorrow.
You should be receiving UPS tracking from me and a pickup notice from UPS late in the day tomorrow.
Best;
Wayne
Flatbanker in action
Spiller vel som forventet... Venter på ny AT OC 9 XML så venter med dommen til da... Ortofon Vivo red som jeg bruker nå har ukjent tilstand...
Har og standard ubalansert armkabel og det trekker vel ikke akkurat opp...
nå er jeg tydeligvis tilbakestående angående kobling strøm, men er det common eller AC FG som skal inn i G kontakten mellom v+ og v-?
ref meldingen du sendte til habicht om at du koblet 1-4-5 til 15v og 2-3 til 5v
jeg monterer også min i en plastboks, så har ikke jordet chassis - burde jeg lodde en kabel fra FG punktet på kortet til FG på strømforsyningen?Variable Termination and Connection Diagram for the Flat Balanced Input Moving Coil Phono Preamp
I'm frequently asked how to do switchable termination for the Flat Moving Coil Preamp
The simplest termination scheme uses a 6 pin female connector plugged onto the termination jumper header. This option provides four values: 10, 30, 100 and 1KΩ or any three values <1KΩ plus 1KΩ.
The switch wires directly to the header and uses the on-board resistors.
A Mouser BOM for the female housing and pins is here: https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=08ae674507
For more than four values a 2 pole 6 position miniature rotary switch such as the NKK MRA206 can be used with resistors mounted on the switch and located at or near the XLR input connectors.
NKK MRA206 2 pole 6 position switch:
Here is a connection diagram for the Flat Moving Coil Preamp showing switchable input termination.
Large format: https://ka-electronics.com/images/p...gram_With_Switchable_Termination_012923-1.png
The NKK MRA206 pinout (front view) looks like this:
Resistors R1-R6 are in parallel with the internal 1KΩ bias resistors and larger values require calculating termination with them in parallel.
The values of R1-R6 can be calculated by:
1/Rdesired - 1/1000 = 1/Ractual
So for a 400Ω termination:
1/400 - 1/1000 = 1/Ractual = 667Ω = 665Ω rounded to an E96 value.
A spreadsheet to calculate Moving Coil Input Termination is here: https://ka-electronics.com/calculators/Moving_Coil_Termination_Calculator.xls
Two Input with Independent Termination
Large format: https://ka-electronics.com/images/p...nput_With_Switchable_Termination_012923-1.png
For two inputs with only one termination selector move the switch connections to after the 4PDT switch.
Mouser Project Manager link for the NKK 4PDT (gold contacts) and MR206 Rotary Switch: https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=e465205d3a
On the BOM above the switch that includes the knob is about $2 less expensive.
A similar NKK rotary switch wired with resistors. This one is a hastily-wired 12 position mic preamp gain switch I use on the bench.
Tip: When wiring the switch be sure to solder the lead to the center common pins before installing the resistors. If you don't you won't be able to get the soldering iron tip into the recess formed by the resistor bodies.
A DIN power pigtail for the Meanwell P25A:
More construction information here: https://www.proaudiodesignforum.com/forum/php/viewtopic.php?t=1179Da spiller det!
Og vinner estetikk-prisen gjør jeg vel også
Finere boks får komme senere en gang, når jeg begir meg ut på flere innganger og ekstern load-justering.
Og lyden?
Naturligvis farlig å uttale seg etter kun et par låter, men akkurat som når vi testet hos @habicht er det umiddelbare inntrykket at man får litt mer av alt.
Har ikke justert så mye etter at ART9 kom i hus siden jeg ventet på å få Flatbankeren opp å gå, så blir gøy å fortsette tweaking av oppsettet nå som jeg kan sove godt og vite at RIAA'en ikke lenger struper signalet
Faen, det tenkte jeg ikke på!Kan selvfølgelig være kabel magi som står for godlyden
Der har vi detKan selvfølgelig være kabel magi som står for godlyden
Klar for å flytte strømforsyning, ny armkabel er montert med balansert Mogami kabel og Neutrik gull plugger
Hana ankommer i morgen
SSlettet medlem 32125
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Ivrig nåKlar for å flytte strømforsyning, ny armkabel er montert med balansert Mogami kabel og Neutrik gull plugger
Hana ankommer i morgen
Vis vedlegget 888578 Vis vedlegget 888579 Vis vedlegget 888580
Fått opp farta vettuIvrig nå
Vært lite hifi det siste året, men Inspirert av framdriften her har jeg nå varmet opp loddebolten, og har montert ferdig kretskortet til flatbankern. Har også delene til strømforsyning liggende etter innkjøp i fjor, men kjøpte selvsagt for liten boks, så det må vente litt.Vedlegg
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Åssen technics spiller er den store grå klumpen som er felt ned i plankenJa nå koser vi oss!
Vis vedlegget 888563
Tenk at en så "simpel" sak i en plastboks fra Clas kan spille så bra!
Vis vedlegget 888568
Noe du har modifisert selv?
En Technics SL-1000mk2p fra svensk radio - den er original, bortsett fra at jeg har kledd den i ny valnøttfiner.Åssen technics spiller er den store grå klumpen som er felt ned i planken Noe du har modifisert selv?
SSlettet medlem 32125
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Ok. Den var stilig.
Thank you everyone for your support! I'm glad to see so many units packaged and being used.
This is my preamp in a Hammond enclosure. I used "D" connectors in order to quickly switch preamps between MC and MM. The 9 pin Ds are pinned out such that if one were to absent-mindedly plug the audio/DC cable directly into the cart leads power would never be applied to the cart.
I would highly recommend everyone powering the preamp up the first time to measure with a meter to make sure there's no DC potential at the inputs that could be applied to the cart. A few mV (in common mode from input to ground) is permissible but in the event the DC supply were connected improperly there could be problems. Do make sure the DC connections at the Phoenix are nice and tight. The assembly and test instructions cover checking the inputs: https://proaudiodesignforum.com/ima...ly_And_Test_Instructions_FMCP_28_012622_1.pdf
These preamps were designed for cutting facilities where the preamp is mounted at the lathe and remote from the RIAA board and/or AD converter and monitors. There is about 50 feet of balanced audio and DC power cable between the Flat Preamp and RIAA EQ Monitor Switcher board. All of the noise measurements I show for my MC and MM preamps with carts as sources are measured with these long cables. The cart leads are fully-balanced and only about 3 feet long.
Some of my clients use the RIAA EQ Monitor Switcher's line input as a second turntable input. The board can also be jumpered for Inverse-RIAA and is used as the actual cutting amp for both feedback and non-feedback lathes.
The pinout discrepancy on the Meanwell supply is due to the difference in 180° DIN and 240° DIN conventions. The actual male plug, as those of you that have one know, is 240°, but the label is for the 180°. I found this chart which explains the differences. Until these supplies I'm not sure I'd ever seen a 240°.
SSlettet medlem 32125
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Hello, do you have picture of the contacts? Nice workThank you everyone for your support! I'm glad to see so many units packaged and being used.
This is my preamp in a Hammond enclosure. I used "D" connectors in order to quickly switch preamps between MC and MM. The 9 pin Ds are pinned out such that if one were to absent-mindedly plug the audio/DC cable directly into the cart leads power would never be applied to the cart.
I would highly recommend everyone powering the preamp up the first time to measure with a meter to make sure there's no DC potential at the inputs that could be applied to the cart. A few mV (in common mode from input to ground) is permissible but in the event the DC supply were connected improperly there could be problems. Do make sure the DC connections at the Phoenix are nice and tight. The assembly and test instructions cover checking the inputs: https://proaudiodesignforum.com/ima...ly_And_Test_Instructions_FMCP_28_012622_1.pdf
These preamps were designed for cutting facilities where the preamp is mounted at the lathe and remote from the RIAA board and/or AD converter and monitors. There is about 50 feet of balanced audio and DC power cable between the Flat Preamp and RIAA EQ Monitor Switcher board. All of the noise measurements I show for my MC and MM preamps with carts as sources are measured with these long cables. The cart leads are fully-balanced and only about 3 feet long.
Some of my clients use the RIAA EQ Monitor Switcher's line input as a second turntable input. The board can also be jumpered for Inverse-RIAA and is used as the actual cutting amp for both feedback and non-feedback lathes.
The pinout discrepancy on the Meanwell supply is due to the difference in 180° DIN and 240° DIN conventions. The actual male plug, as those of you that have one know, is 240°, but the label is for the 180°. I found this chart which explains the differences. Until these supplies I'm not sure I'd ever seen a 240°.
Mvh pål
Ser ut som D-sub kontakterHello, do you have picture of the contacts? Nice work Mvh pål
SSlettet medlem 32125
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Ser sånn ut. Kult, litt røff lookIt is a DB-9 pinned out like this:
@KA-Electonics.com
Is it ok to leave the phono-amp on all the time or do you recommend a power switch?
My old Graham Slee RIAA didnt have a power button so it didn't cross my mind to add one when i put mine together, so now i am just wondering if i should hurry up and and add one, or do it at a more relaxed pace -
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