Met 1 Upgrade

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Golyd
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Met 1 Upgrade

Post by Golyd »

Hi all.
Im considering replacing the output coupling caps with V-Cap TFTF's, for the 3front or maybe five of the channels, in my 6channel Met1.
It will be connected to a Premier 350SA and McCormack ht-5 wich both have 100k ohm input impedance so i guess 2uf should work fine.

For the sub channel I'm a bit uncertain what to do, the Mj Acoustics ref1 mk3 have an input impedance of 10k ohm.
If I understand things correct the original 4.15uf gives a Optimal low frequency response of 38.3Hz wich seems a bit high for a subwoofer channel.

I could add the replaced original 4uF's to get a total of 16-24 uF. Or I could find a cheaper option to several V-cap's that would work.
Since this is a dedicated sub channel mid and treble perfomance can be ignored.

Any Input would be welcome.

I see that both jeffreybehr and Mr_BT have experience with theese things ;)

Pre Amp: Conrad Johnson Met 1
Main Speakers Amplifier: Conrad Johnson Premier 350SA
Surround Amplifier: McCormack HT-5
Blu Ray: Oppo 105
Front Speakers: Boston Acoustics VR-M90
Center: Boston Acoustics VR-920
Rear: Boston Acoustics VR-MX
Sub: Mj Acoustics Ref 1 Mk3
jeffreybehr
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Re: Met 1 Upgrade

Post by jeffreybehr »

Tore, replacing coupling caps in the MET1 will be a rewarding upgrade. C-j's combination of 4uF 'propylenes and 0.15uF 'styrenes always sounds good and not edgy, but better coupling and PS-bypass caps will increase transparency substantially. If I were doing mine again, I'd still use Sonic Craft 2uF Platinums (Teflon-alloy-film) in the front-L/R channels and a MultiCap RTX (polystyrene) bypassed with trio of small Platinums in the center channel and do nothing with the surround and SW channel. You'll spend many-hundred$ unnecessarily (IMO) purchasing 5-star coupling caps, especially the hyper-expensive V-Cap TFTFs, for the surround and SW channels...and you may run out of space on the board.

A 2uF coupling cap in the front-L/R channels driving your net-83K* load will produce a high-pass-filterpoint (HPFP)** of c. 2.0Hz, an ideal number***, so you're good there. The SW channel's original 4.15uF driving net-9.8KOhms creates an HPFP of 3.9Hz, not 38Hz. But even 3.9Hz is too high, so how 'bout adding one of the removed 4uF original 'propylenes to the existing 4.15uF pair for 8.15uF and 2.0Hz?

I followed the advice of Jeffrey Glowacki of Sonic Craft on the main-PS-bypass caps, replacing Cs 41 and 94 with a 2.2/630 Jupiter HT and a 0.22 Platinum and Cs 33, 92, and 93 with another Jupiter 2.2/630 HT and a 0.01 Platinum. I suppose one could try to further increase the quality of the final PS-output caps 13 and 89 (30/400 'propylenes), but I have no idea what one might use there with the space limitations.

Image

Good luck. Do let us know what you decided.


* There's a 500K load resistor in the preamp that's in parallel with the poweramp load.
** The formula is F = 159155/RC, where F = frequency of -3dB point in Hertz, R = load resistance in Ohms, and C = capacitance in microFarads.
*** A HP filter point at least 3 octaves below the nominally-lowest frequency one wants to pass, that being 20Hz, is as low as one needs to use, altho lower doesn't hurt--it's just more expensive. :)
Tin-eared audiofool, large-scale-Classical-music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Golyd
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Re: Met 1 Upgrade

Post by Golyd »

Thank you for the reply Jeff, it's higly appreciated!
After reading alot of reviews I think I want to try Duelund Cast PIO in 2uf, hoping that I will be able to fit them in some way (62mm diameter and *66mm height)
The descriptions I have read of the three candidates, Vcap, Sonicap and Duelund leaves mee with a feeling that they will fit my taste the best, as in the "warm" direction.

I will limit the upgrade to the 3 front channels. (Thanks for giving me a push away from replacing all five)

For the sub channel, is there any downside to adding more than 1 4uf, i.e 2-or 3 of the original replaced caps, other than space limits? This channel will probably only be used with the lowpass filter set to around 25Hz, and I wont use them for anything else..

(The powersupply has already been upgraded with V-caps by RHB sound design.)

Thanks
jeffreybehr
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Re: Met 1 Upgrade

Post by jeffreybehr »

Golyd wrote:Thank you for the reply Jeff, it's highly appreciated!
YW.

For the sub channel, is there any downside to adding more than 1 4uf, i.e 2-or 3 of the original replaced caps, other than space limits? Not that I know of.
This channel will probably only be used with the lowpass filter set to around 25Hz, and I won't use them for anything else.

(The powersupply has already been upgraded with V-caps by RHB sound design.)

Thanks
Tin-eared audiofool, large-scale-Classical-music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Mr_BT
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Re: Met 1 Upgrade

Post by Mr_BT »

Golyd,

You're in good hands already, I see..... Jeffrey has guided me through the process and has given me support during tough times :) TYVM Jeffrey!!!

I can only tell you: Listen and trust your ears.... I know, experimentation in the capacitors field may cost a lot but at the end what your hear, and what pleases you the most is the goal....

BTW, still being tempted by SCP Teflon.

P.S. don't get too wind up in -3db point.....different capacitors brands may give you different perception of lower registers response at given uF value.
Also, synergy of audio path components is crucial.
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