Phono stage Board

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Latteman
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Phono stage Board

Unread post by Latteman »

I’ve had good n bad fortune with Nva MM phono stage- regulator failures- usually my fault with multi meter probe slippage as mentioned in other posts today.
Nva have always been sympathetic and assisted where possible- the result is I am fortunate to have MM & MC boards— lack of a suitable enclosure had me using the mm only with an Ortofon SUT. Always been pleased with this but oh boy finally getting an enclosure for the mc board has really been a game changer
The difference is night n day- an up lift in music presentation, it’s brought life to cartridges I thought were dull, ordinary n safe- a real joy to listen to.
The unfortunate side is an additional box and especially a power socket needed for power on an already busy area.
If u know the Nva phono board u know how it is powered- do u think it’s possible to power both boards from a psu, share 0v, -v & +v so both are continuously powered and the inputs separately selected to allow signal to mm or mc and then onto the pe amp-?
I asked Doc if a mm mc phono stage was possible and he thought there was no room in current boxes- so I forgot about it until now. I assume it would be a larger box or 2 separate for boards & psu- I could live with the latter
I would be willing to try this but would be nervous- any advice etc much appreciated

Anyway- the Nva mc phono board is amazing- so much better than mm & Sut
Cheers
Analogue Source -
Denon DP47f- Ortofon mc20 supreme
Ifi Zen Phono
Doug Self balanced Pre amp
Akai 4000DS mk2 R2R
Digital Sources- IfI stream, Ifi Neo idsd Dac; Tidal / Radio Paradise
Amplification Nva 30vdc mono blocks
Speakers Lii Audio F-15 in Open Baffle; Ls6
Weiduka AC8.8- for digital sources
Mini BMU for analog sources

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r3xj0hn570n
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Re: Phono stage Board

Unread post by r3xj0hn570n »

I had a Threshold preamp once. It had an external MC headamp, powered from a socket in the back. I'd suggest that would be the way forward if you have no space left. No problem powering any reasonable number of preamp boards from the main power supply, their actual power consumption is so small. They sound better with an external PSU of course.

I built an NVA phono board into my KD600, directly wired to the cartridge, no connectors except the cartridge pins, external PSU for both the board and TT circuitry. That worked really well. Another option.
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Latteman (Sun Jan 16, 2022 11:01 pm) • karatestu (Mon Jan 17, 2022 6:18 am)

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Latteman
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Re: Phono stage Board

Unread post by Latteman »

Hmmm, food for thought 👍🏼
Analogue Source -
Denon DP47f- Ortofon mc20 supreme
Ifi Zen Phono
Doug Self balanced Pre amp
Akai 4000DS mk2 R2R
Digital Sources- IfI stream, Ifi Neo idsd Dac; Tidal / Radio Paradise
Amplification Nva 30vdc mono blocks
Speakers Lii Audio F-15 in Open Baffle; Ls6
Weiduka AC8.8- for digital sources
Mini BMU for analog sources

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karatestu
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Re: Phono stage Board

Unread post by karatestu »

I would say you can power MM and MC boards from the same power supply. As Rex says, the current draw is tiny. I presume the MM and MC boards use the same DC voltage? In fact I thought the boards were the same apart from two or three components ?

Just don't try putting a switch in the DC lines as the switch will probably fail. So both boards will be at idle all the time. You would of course need to be able to switch the signal between MM and MC unless you power everything down and switch interconnects (PITA).

If only a few components are different then surely there is a clever way to use the same board and just switch between the two sets of different components? Many use plug ins on the back panel- will require flying leads from boards to back panel. Or maybe a switch can be used if you can find one with enough poles ( = number of components to switch). Double throw is all you would need (= number of options).
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Re: Phono stage Board

Unread post by karatestu »

r3xj0hn570n wrote: Sun Jan 16, 2022 10:59 pm I built an NVA phono board into my KD600, directly wired to the cartridge, no connectors except the cartridge pins, external PSU for both the board and TT circuitry. That worked really well. Another option.
Happy new year Rex.

From the above I presume you mean building the phono board ( and regulators) into the turntable chassis like a Naim Prefix. I often thought of doing that as it is said there are considerable benefits to having extremely short signal wires from cartridge to phono stage. Only gotcha is having it near to the TT psu and motor but off boarding the TT psu would largely take care of that and the phono board could be put in a slimline metal enclosure to protect it from any interference from the motor.

The TT then needs two external power supplies and if you want to swap TT's then it's not so straight forward.
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r3xj0hn570n
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Re: Phono stage Board

Unread post by r3xj0hn570n »

karatestu wrote: Mon Jan 17, 2022 7:01 am
Happy new year Rex.
Back at ya Stu.
karatestu wrote: Mon Jan 17, 2022 7:01 am
From the above I presume you mean building the phono board ( and regulators) into the turntable chassis like a Naim Prefix. I often thought of doing that as it is said there are considerable benefits to having extremely short signal wires from cartridge to phono stage. Only gotcha is having it near to the TT psu and motor but off boarding the TT psu would largely take care of that and the phono board could be put in a slimline metal enclosure to protect it from any interference from the motor.

The TT then needs two external power supplies and if you want to swap TT's then it's not so straight forward.
The motor housing is made from quite thick steel, no external magnetic fields noticed. I made the external PSU at the same time as i installed the phono boards under the TT, so only one box and a multipin connector. It is really quiet, good enough to run straight into an ADC and archive lots of records.
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karatestu (Mon Jan 17, 2022 9:05 am)

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