The six-channel MET1

[pstrisik]

I have output from my DAC both to the CJ pre and my Onkyo pre/pro. When I'm listening to two channel, I play stereo through the pre and let the pre/pro output to the subs. Added benefit is separate volume controls for the mains and sub. Two remotes unless you use a universal (I have an Harmony).

[admin]

Thanks for the knowledge! I definitely don't want my signal going through the emotiva for 2 channel music. I think your 2nd recommendation of taking the L and R rca's out from my MET1 into the subwoofer and then using the RCA pass through on the subs to my yamamoto amplifier. Do you think going through the pass through connection will degrade the sound at all. Also does the LFE signal have different bass information than the L/R speakers? Another option would be for me to get a Y connector to hook up to my L/R outputs instead of using the pass through on the subwoofer amp. What do you think would be best to not degrade the sound, my avantgarde horns are pretty revealing. Thanks!!

If it is a good sub, the degredation in the audio signal by using the sub as a pass through should be very minimal. In regards to the LFE signal having different bass information than L/R speakers question: Are you asking whether L and R fronts in a 5.1 encoded source is different than the "x.1" LFE channel, then yes, it is different. The LFE channel in multichannel formats is unique from the rest of the channels.

At the end of the day you may have to do some experimentation to find out what sounds best to you. I have heard systems with subs used as passthrough that sounded completely transparent, to systems that did not mesh well. Let us know what you decide, good luck!

[Malcolm02]

I'm using the Oppo 105 with the MET1. I have both the 5.1 outputs going to the multichannel inputs on the MET1 and the stereo outs going to one of the stereo inputs. That way I can enjoy the full benefits of channel 5.1 sources and utilize the ARM feature with stereo sources.

Some people are using the Oppo going straight into a multi-channel power amp and using the software volume control in the Oppo. I'm sure that gives good results if you only have a small number of digital sources. I could get away with it, but I like the added warmth of tubes and the flexibility to use other analog sources, even though I don't have any other essential analog sources, just another DAC that is kind of redundant now and a tuner that I don't really use.

The drawbacks of this setup are that I can only do 5.1, not 7.1 or more, and there are no balanced connections, but this is fine with me. Also there is no room correction software going on or possible, but maybe Oppo will incorporate it into a future player.

I don't know why people are discussing using a processor with the MET1. I thought the whole point of the MET1 was to integrate a tube preamp with a home theater system. If you're using a processor why don't you use a 2-channel tube preamp with home theater bypass instead of the MET1?

[jeffreybehr]

I'm using the Oppo 105 with the MET1. I have both the 5.1 outputs going to the multichannel inputs on the MET1 and the stereo outs going to one of the stereo inputs. That way I can enjoy the full benefits of channel 5.1 sources and utilize the ARM feature with stereo sources.

Some people are using the Oppo going straight into a multi-channel power amp and using the software volume control in the Oppo. I'm sure that gives good results if you only have a small number of digital sources. I could get away with it, but I like the added warmth of tubes and the flexibility to use other analog sources, even though I don't have any other essential analog sources, just another DAC that is kind of redundant now and a tuner that I don't really use.

The drawbacks of this setup are that I can only do 5.1, not 7.1 or more, and there are no balanced connections, but this is fine with me. Also there is no room correction software going on or possible, but maybe Oppo will incorporate it into a future player.

I don't know why people are discussing using a processor with the MET1. I thought the whole point of the MET1 was to integrate a tube preamp with a home theater system. If you're using a processor why don't you use a 2-channel tube preamp with home theater bypass instead of the MET1?

Amen.

[pstrisik]

I thought it was a question of using the MET or a pre/pro, not both.

........Peter

[Malcolm02]

I thought it was a question of using the MET or a pre/pro, not both.

Oh ok, maybe I misunderstood. Then just ignore my last paragraph and I think the rest of my post answers the question anyway.

I have had my MET1 for only a few weeks but I'm loving it.

Malcolm

[Malcolm02]

I'm using the Oppo 105 with the MET1
blah blah blah

Amen.

Hi Jeffrey,
Thanks for your endorsement of my post. When I was researching the MET1 I came across several of your posts and I learned a lot from them.
Malcolm

[scottm_dj]

Hey all...I posted an inquiry here about 4 years ago and I just ran across one of these for a good price and thinking of getting it. I have used the MAP1 since that post so I would definitely miss it's operation (and ARM circuit!). I also realize I could do an "SMC audio" upgrade on my MAP1 for this cost...are the CJ parts that much superior as so much of the unit is alike...?

A couple questions: tube life is unknown on the MET1 unit in question...what type do they take and how do you know when they go bad? How much approx do they run apiece for "run of the mill" non-exotic ones? Also, with the MAP1 i usually keep it on all the time as it sounds best warmed up...but the CJ would wipe out the tubes quickly doing that i think? Is 'standby' mode enough to disengage the feed to them?

Finally...after all this time I didn't know holding MUTE 3 seconds works to put the MAP1 in standby! It's only listed in the CJ manual--not MAP1

Thanks!

[jeffreybehr]

Hey all...I posted an inquiry here about 4 years ago and I just ran across one of these for about $1500 and thinking of getting it. I have used the MAP1 since that post so I would definitely miss it's operation (and ARM circuit!). I also realize I could do an "SMC audio" upgrade on my MAP1 for this cost...are the CJ parts that much superior as so much of the unit is alike...?

A couple questions: tube life is unknown on the MET1 unit in question...what type do they take and how do you know when they go bad? How much approx do they run apiece for "run of the mill" non-exotic ones? Also, with the MAP1 i usually keep it on all the time as it sounds best warmed up...but the CJ would wipe out the tubes quickly doing that i think? Is 'standby' mode enough to disengage the feed to them?

Finally...after all this time I didn't know holding MUTE 3 seconds works to put the MAP1 in standby! It's only listed in the CJ manual--not MAP1

Thanks!

(1) If you don't buy this $1500 MET1, PLEASE e-mail me at jeffreybehr(at)cox(dot)net so that I can.
(2) The MET1 has an ARM circuit; what will you be missing with the MET1?
(3) The MET1 uses Mullard M8080s or Mullard CV4058s**, six of them. The American number for that is 6C4, but the vast majority of 6C4s that I bought and tested were very microfonic and useless for audio. Look for M8080s/CV4058s on eBay; I've bought lots and never received a bad one. I use my system an average of maybe 3 hours a day or 1000 hours per year, and I recommend changing at least the tubes for the three front channels every two years. I love to twiddle with this stuff and have found enough 6C4s and 6135s* to be able to use them in the surround and bass-effects channels.
(4) Yes, both filament and plate Voltages are off in standby.
(5) The MAP1 has no coupling caps that I can find in the circuit diagram I have, so one doesn't have to spend money replacing them! There is a 0.47/200 12VDC-Voltage-rail-bypass cap for each positive and negative rail in each channel (that's 2 caps per channel = 12 caps), but if I were improving it, I'd replace the pairs only in the front-three channels. There is also a pair of 0.5/200 bypass caps in the PS that I'd replace. IMO comparing the cost to upgrade the MET1 and MAP1 is foolish; they are MUCH different in circuitry. For instance, the retail value of Teflon-film coupling caps in the MET1 could easily be over $2K for all six channels.

Remember, PLEASE e-mail me if you DO NOT buy that MET1.


* the heavy-duty version of the 6C4
** the British-military number for the M8080

[scottm_dj]

*Update* I did decide to get the unit The source is actually the technical officer for Oppo in Europe (!)...so he's been bit a bit busy of late as you might imagine as they prep their 4K spinner for the holidays (yes, the one you see quoted in the first looks of the 203). The MET1 is in pristine shape as I would expect from that owner--and also had 3 main ch extra Mullard tubes (valves) ordered from the premier source Watford. As you can see from the attached pic it's getting close to making its journey back to the states...so I'm excited about that. All told with shipping it's going to be about 2 grand total (still we endure terrible GBP/USD conversion). I figure it if doesn't "jibe" in my current MAP1/HT5 system for whatever reason, its coveted enough to be a pretty EZ re-sell if it comes to that...

[admin]

Congrats on the purchase.

Also, I'm excited to hear that oppo is releasing a 4k player.

[jeffreybehr]

Congrats, Scott, I'm sure you'll love it.

[scottm_dj]

Oppo: Yes...but they are taking their time to get it right. Only a 103 equivalent now with a 105 enhanced update to follow. THis article probably describes it best--pics of the new interface and the DAC info (swiched to AKM). http://www.trustedreviews.com/oppo-udp-203-review

[admin]

Oppo: Yes...but they are taking their time to get it right. Only a 103 equivalent now with a 105 enhanced update to follow. THis article probably describes it best--pics of the new interface and the DAC info (swiched to AKM). http://www.trustedreviews.com/oppo-udp-203-review

Great article. I'm not to the point of upgrading my system to 4K just yet, but as soon as 4K projectors start hitting the market at more reasonable prices I plan to upgrade. I'm almost certain that my player will be an Oppo as I have owned a few of their units in the past and have always been happy with their products.

[scottm_dj]

Ok all..I finally got the CJ from jolly 'ol England to the US I have to say...other than a noisy center channel (only) which may be a bad tube and the royal pain of inverting polarity, the sound is definitely more refined and transparent than the McCormack--and more gain too. Sounds fantastic for sure...or did. It was heaven for about 90 min until..boom..all sound ceased immediately. It now just plays about the same volume as a turntable cartridge level--no matter what the volume there is little to no amplification.

At first i thought something had happened with my McCormack HT5 amp...but a quick direct hook up had sound in connected channel. A closer look and reading of the CJ manual is now having me pinpoint the tube control fuse. Notice in the attached pic how dark that cavity is...i do believe they are supposed to noticeably glow? It can't be the power fuse (turns on normally), it can't be the control fuse (switches inputs, etc), so there's only one left. I would think it would give some kind of warning if the fuse circuitry was inactive, yet turn on normally after the lengthy wait time. I can't take it apart just yet but I bet someone here knows exactly what's going on...any advice? Am i correct targeting the tube fuse?

Resized_20161103_182544.jpeg (636.07 KiB) Viewed 1255 times

BTW...I know some of you are probably thinking 230v vs 120v differences for UK vs US. That was professionally addressed (modified) before being sent over back to its homeland. However, I did notice the fuses have different ratings and blow twice as quickly for 230v version...so i wonder which ones are installed. Probably have to wait til weekend to dig more....

A couple more fun pics from the Oppo CJ source: .a custom halloween pumpkin...and the beautifully packed up CJ ready to ship among a warehouse of new Oppo products ready to hit retail

IMG20161028195934.jpg (2.51 MiB) Viewed 628 times

IMG20161025160458.jpg (2.49 MiB) Viewed 628 times

[plurn]

... Notice in the attached pic how dark that cavity is...i do believe they are supposed to noticeably glow? It can't be the power fuse (turns on normally), it can't be the control fuse (switches inputs, etc), so there's only one left. I would think it would give some kind of warning if the fuse circuitry was inactive, yet turn on normally after the lengthy wait time. I can't take it apart just yet but I bet someone here knows exactly what's going on...any advice? Am i correct targeting the tube fuse?
...
BTW...I know some of you are probably thinking 230v vs 120v differences for UK vs US. That was professionally addressed (modified) before being sent over back to its homeland. However, I did notice the fuses have different ratings and blow twice as quickly for 230v version...so i wonder which ones are installed. Probably have to wait til weekend to dig more....
...

Hi scottm_dj,

From your question about whether the tubes should glow, it depends on the tube though it is likely you are correct. For example the small signal tube in my ET5 has a slight but noticeable glow.

Anyway, it sounds like you have this well in hand. Based on your comments and a quick look at the manual, I would guess that the wiring was changed to support 120v, while the fuses may not have been changed to suit. I think you may be leaning towards the same guess. If that is correct, then the fuses may be under-rated for current for running at 120v. For a given amount of watts consumed, half the mains voltage would require double the current drawn, so would need fuses with a higher amp rating. I agree with your troubleshooting that it may well be the tube fuse that has blown. It will be easy to check when you open it up to check the ratings on the fuses, and their condition.

You may be aware of this but I will state it anyway as it might help someone one day. The voltage rating of the fuse is not critical as long as it is a bigger number that the voltage you are running the device at. The important rating is the current (in amps). So from the manual:

"If configured for 100 or 120V:
F1 1/2 amp, slow blow
F2 1/4 amp, slow blow
F3 T800ma

If configured for 220 or 240V:
F1 1/4 amp, slow blow
F2 1/8 amp, slow blow
F3 T400ma"

Taking the example of F2, when running at 240V mains power, a fuse of 125mA/250V (125mA = 1/8amp = 0.125A) slow blow would be suitable.
When running at 120V mains power, a fuse of 250 mA/250V slow blow would be suitable (as would a fuse of 250 mA/125V slow blow). The 250V rating of the fuse does not need to match your mains power, it just needs to be => it. That is my understanding anyway - though I could be wrong. Happy to be corrected.

Good luck and hopefully it is just a blown fuse and nothing serious.

Anthony

[scottm_dj]

Thanks Anthony. Curious to see what Jeffrey thinks as i think he has a pretty intimate knowledge of the MET internals

One more thing I've seen listed somewhere but can't readily find: does anyone know which tube corresponds to which channel? For instance, the rushing noise was center channel only---so which tube would i be looking at possibly being bad? I also wonder if it was SO bad it tripped the fuse...

[plurn]

From the schematic it looks like V5 6C4 is centre (CTR on the schematic).

V1 LF left Front
V2 RF
V3 LF left rear
V4 RR
V5 CTR

viewtopic.php?f=17&t=128 In "Part 1" Schematics file

Anthony

edit: not sure if that helps. I don't have a MET1 so I don't know if each tube position is labeled?

[jeffreybehr]

Thanks Anthony. Curious to see what Jeffrey thinks as i think he has a pretty intimate knowledge of the MET internals

One more thing I've seen listed somewhere but can't readily find: does anyone know which tube corresponds to which channel? For instance, the rushing noise was center channel only---so which tube would i be looking at possibly being bad? I also wonder if it was SO bad it tripped the fuse...

To paraphrase a well-known movie line, I don't know nothin' about birthin' no AC-power fuses, but tube positions I know! With the preamp positioned normally and you staring at the front panel, the back row of two tubes contains the Center channel's tube on your left and the '.1' or SW channel's tube on the right. The front row of four are, from the left, LF, RF (making the three front channels' tubes all in the left-hand half of the tube bay), then the LR channel third from the left (and 2nd from the right) and the RR channel's tube far right. Let's see if I can diagram it:
Left edge, rear row------------------C-------------SW-----------------------Right edge
Left edge, front row------LF--------RF------------LR--------------RR------Right edge.

Hint--NEVER turn the preamp on with a tube or tubes missing, and never remove a tube with the preamp turned on. Doing either will 'blow' that channel's output-buffer FET, and then that channel won't operate.

I can't imagine a tube's noise performance causing a tube to blow, but using a fuse with half the correct current rating sure will.

[scottm_dj]

Ok guys...I just checked the fuses. The plot thickens

US power fuse should be T800...and it IS

US fuse F1 should be 1/2amp...and is is 1/4. UK spec as I suspected

US fuse F2 should be 1/4 amp...and is is....very interestingly T500 so 500ma which is 1/2 amp. Uk spec is 1/8 amp. This could be an issue.

None of the fuses appears blown but i bet F2 is the tube fuse and didnt have a low enough value in it. What do you all think?