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MX110z Tube positions and recommendations

Alfmonster

Alfmonster

Active Member
Hello AK,

I’m trying to get more familiar with the MX110z and have been a bit confused by the tube positions. Unfortunately most all of the tube ID is gone from the preamp. Is there something to explain this a bit more simpler than the schematic?

I’ve also read that the most significant effect comes from changing the 12ax7 phono tubes and the 6u8 tubes. Is there any recommendations as to specific brands or other tube positions that would work well if changed? And also, should all 4 of the 12ax7’s be matched? Tele’s seem to be selling for top dollar these days - would 4 unmatched RCA black plates work alright? I have 3 - would need to pick up one more.

I’m trying to tune this more specifically for Jazz and classical records.

Currently, the Mx110z is paired with a mc225.

As always, thank you so much.
 
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Tele 12ax7 for the v1 position is my choice. I don't use phono so I have cheapies in the two phono spots. Rca black plate 6u8 are the best of that variety I have heard. The first position 12ax7 is most influential sound wise in my experience.
 
mnmmt said:
Tele 12ax7 for the v1 position is my choice. I don't use phono so I have cheapies in the two phono spots. Rca black plate 6u8 are the best of that variety I have heard. The first position 12ax7 is most influential sound wise in my experience.
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this is great information — thank you!

I took a screenshot of a section from a tube layout of a MX110 I found online and circled the tubes I think you are talking about?

The RCA 6u8 black plates and the tele 12ax7 would go in these spots?

also, do the 6u8 tubes all need to be matched?
 

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The single 12ax7 in the circle is the one I referenced that all audio signal goes through. Balanced sections of that tube are good since each half handles one channel, but I have never tested mine. The two 6u8 you circled are the amplifiers, one for each channel. It would be good to match them but I had never tested mine. The other two 12ax7 are the phono section so whether you get fancy tubes for those will depend on whether you listen to a tt. All the other tubes on that are for fm and really can't affect the sound (except the 6d10 which was only ever made by one company and can't be tube rolled).
 
mnmmt said:
The single 12ax7 in the circle is the one I referenced that all audio signal goes through. Balanced sections of that tube are good since each half handles one channel, but I have never tested mine. The two 6u8 you circled are the amplifiers, one for each channel. It would be good to match them but I had never tested mine. The other two 12ax7 are the phono section so whether you get fancy tubes for those will depend on whether you listen to a tt. All the other tubes on that are for fm and really can't affect the sound (except the 6d10 which was only ever made by one company and can't be tube rolled).
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Your explanation helped so much — Thank you! I’m looking into some 6u8 black plates - hopefully I can find a good matched pair although I don’t know how trustworthy eBay is.
 
mnmmt said:
Brent jessee tubes is very good to deal with and you can have them selected and matched.
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Thank you!! Just looked up his site, will call him Monday. His prices are so reasonable. It’s always such a stressful crapshoot with eBay.
 
Yes, he seems to have everything. I picked up a spare 6d10 and one of those little metal ones (6ds4?) last time I bought from him. I have an electronics surplus shop nearby that had all the other tuner tubes I needed so I think I am good for the next 50 years or so.
 
mnmmt said:
Yes, he seems to have everything. I picked up a spare 6d10 and one of those little metal ones (6ds4?) last time I bought from him. I have an electronics surplus shop nearby that had all the other tuner tubes I needed so I think I am good for the next 50 years or so.
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haha that has now become a legitimate worry of mine — about eventually not being able to acquire the dwindling supplies of vintage or rare tubes. Also good to know about the rare 6d10 tube. I’ll also ask Brent about those as well
 
clinic-audio said:
Hello Alfmonster

thank you for using my drawing and I am happy to see that it was helpfull for you !
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hello!! It’s nice to see you again on audiokarma!

That was your image?? The internet is so such a small place - but thank you for contributing that drawing to the archives it helped me (and I’m sure countless others) so much.

a question I had when looking at the image, is the tube layout different for the different versions of the Mx110? Like in your image I don’t see the 6d10 tube where it is on the MX110z.

also your advise about the MCD7007 cd wobble helped so much and it’s still working great!
 

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Hello Alfmonster

Really happy to help you with your MCD7007 who is working now !
yes , I see my picture (complete this time ) on the left ! do you know why we can see the 6D10 on your MX110 picture ?
Because it is a MX110 Z . Only the MX110 Z has a compactron !
On my picture this is a MX110 M (first generation without compactron of course !)
There is also the X serie but there is no EM84A for "magic eye" but a 6HU6 as "magic eye"
 
clinic-audio said:
Hello Alfmonster

Really happy to help you with your MCD7007 who is working now !
yes , I see my picture (complete this time ) on the left ! do you know why we can see the 6D10 on your MX110 picture ?
Because it is a MX110 Z . Only the MX110 Z has a compactron !
On my picture this is a MX110 M (first generation without compactron of course !)
There is also the X serie but there is no EM84A for "magic eye" but a 6HU6 as "magic eye"
Click to expand...

I’ve been looking but am failing to find a tube layout for the MX110z — Do you know where I might be able to get a tube layout for the MX110z? Also, what did the addition of the compactron and the use of the 6hu6 as the magic eye do?
 
mnmmt said:
Tele 12ax7 for the v1 position is my choice. I don't use phono so I have cheapies in the two phono spots. Rca black plate 6u8 are the best of that variety I have heard. The first position 12ax7 is most influential sound wise in my experience.
Click to expand...

RCA Black plate 6u8 made the most drastic improvement in any piece of tube equipment I have ever owned in the MX110. I normally cannot hear the subtle differences some people hear in rolling tubes in gear. With this exception. Try them there and see if you like them
 
Thocom said:
RCA Black plate 6u8 made the most drastic improvement in any piece of tube equipment I have ever owned in the MX110. I normally cannot hear the subtle differences some people hear in rolling tubes in gear. With this exception. Try them there and see if you like them
Click to expand...

i just ordered a matched pair of RCA Black plates for the L/R and then a third RCA BP 6u8 for that other 6u8 slot.

I have some spare RCA black plate 12ax7 that I’ll try in the phono section and the other 12ax7 slot until I can get some Telefunkens. But they are so expensive now.

Do you know which valve position affects the aux? I have the CD player going in there.

Unfortunately my Mx110 is at AudioClassics for repair due to a malfunctioning selector switch - so I will be ready and waiting to give the new tubes a go.
 
Watch out on the tuner section tubes - if you swap those out you will need a tech to rework/align the tuner.

My preferences:

6U8 French/Radiotechnique dual support getter, late '60s early 70s. This is the best 6U8 that ever landed in my MX110, that includes RCA. Tele, Tung-Sol. It's the best for audio in that tube I've seen. Appears in Amperex (usually globe logo) as well as Valvo. When searching, try "ECF82" as these are how they typically are packaged. Unsung tube, because no body besides Mc MX110 uses them really these days, save for a few tuners out there maybe....

12AX7: Telefunken, this is a no brainer and where the "magic" of these vintage Macs come from in part. The 6U8 is the exception, the French/RT beats it. But in 12AX7 for MX110 or MC30/240/etc the Teles are fab.

On the aux, that bypasses the 6D10, then the tubes are the singular 12AX7 and 6U8 as a trio which flavor the line stage at that point.
 
Audible Nectar said:
Watch out on the tuner section tubes - if you swap those out you will need a tech to rework/align the tuner.

My preferences:

6U8 French/Radiotechnique dual support getter, late '60s early 70s. This is the best 6U8 that ever landed in my MX110, that includes RCA. Tele, Tung-Sol. It's the best for audio in that tube I've seen. Appears in Amperex (usually globe logo) as well as Valvo. When searching, try "ECF82" as these are how they typically are packaged. Unsung tube, because no body besides Mc MX110 uses them really these days, save for a few tuners out there maybe....

12AX7: Telefunken, this is a no brainer and where the "magic" of these vintage Macs come from in part. The 6U8 is the exception, the French/RT beats it. But in 12AX7 for MX110 or MC30/240/etc the Teles are fab.

On the aux, that bypasses the 6D10, then the tubes are the singular 12AX7 and 6U8 as a trio which flavor the line stage at that point.
Click to expand...

Thank you for all that great information and the very helpful breakdown of which tubes do what. I think it was one of your old posts that I first saw mention of this French Amperex dual support tube. And I’ve been looking for a while but can’t seem to find it. Is there a particular place you might know of that has a stash of these? This particular tube seems extremely rare and a matched pair even more rare.

Great to know about the radio tubes - I won’t touch those. I’ve had the MX110z into the shop so many times due to various malfunctions but I would be so sad if I had to send it back again because I changed the wrong tubes.
 
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