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Moondog 2A3 Monoblocks


Blackbird

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By virtue of my post (from an earlier page) being quoted, I understood "right off" that he was reading through the thread and was at that point inspired to offer his opinion, before having finished catching up.  Done it many times myself...  Slack given.

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4 minutes ago, glens said:

By virtue of my post (from an earlier page) being quoted, I understood "right off" that he was reading through the thread and was at that point inspired to offer his opinion, before having finished catching up.  Done it many times myself...  Slack given.

 

I was guilty of this as well.  But I kept quiet.  😇

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I don't know yet what the new replacement will be for all of the new parts.  He will let me know soon and I trust that he will use the best of parts.  Once I get the Moondogs back, I will take a few photos of the amplifiers' inner.

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On 6/15/2019 at 12:58 AM, Blackbird said:

Well, I have had these pair of Moondogs for 18 years.  This is the first time I am having problem with them about two weeks ago.  Tonight was the first time I opened them in so long I don’t even remember.  I played music on these pair almost every day with my Klipschorns.

 

I'd talk to the tech about replacing all the film capacitors, including the Jensens. 

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  • 3 weeks later...

I finally got my Moondogs back.  They were burned in for about 3 days.

 

All of the caps have been replaced.  All of the sockets and pin holders have been tighten.  The technician told me that according to the schematic, two resistors were wrong.  R10 was suppose to be 2K not 1K and R13 was suppose to be 1.8K not 1K.  Other then that they sound incredible!  The longer they are burned in, the better they get.  Sonically, they sound better then before.  They cost me a total of $450 for parts and labors.  I am extremely happy with the sound.

 

Here are photos of both amps.

 

Moondogs Right.jpeg

Moondogs Left.jpeg

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10 hours ago, Jeffrey D. Medwin said:

No need to leave amp "ON" all the time, if that is what you were doing previously. !!  Its hard on tubes, etc. 

 

Actually, as far as I can remember, I have only left the amps on twice (without turning them off) for a periods of maybe two to three weeks each time.

 

11 hours ago, Jeffrey D. Medwin said:

The technician told me that according to the schematic, two resistors were wrong.  R10 was suppose to be 2K not 1K and R13 was suppose to be 1.8K not 1K.

 

I forgot to mention that he replaced the R10 and R13 resistors since they have the wrong values.  He also replace all of the 10uF/400V caps with 10uF/630V caps.  As of today, the amps are almost dead quiet.  The sonics did not change but got better.

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4 hours ago, awsjr said:

this is magnequest

moondog magnequest.JPG

 

That is interesting.  The schematic Marvel provided is Electra Print but the technician replaced R10 and R13 with the resistors from Manequest parts list.

 

erik2A3 confirmed that my Moondogs indeed have Electra Print OPTs.  I trust the technician but I am wondering why he replaced R10 and R13 from Manaquest parts list?

 

My Moondogs seemed to work great and sonically better then before.

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There is a plausible reason...too tired right now to explain!  Glad you're amps are up and running again and that you're happy with them!  The net values of resistance are actually very similar.  It's not related so much to the output iron brand.  I happen to be working on a pair of Laurel IIs right now, and am just totally impressed by the massive size of the MagneQuest OPTs on the amps.  They are enormous and very Impressive.   

 

It's so great to see these great amplifiers from W. Labs during it's prime.  

 

 

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Erik, I've always wanted to spend the money to put the grid chokes in mine, but never had the cash. You told me at one time that mine had Magnequest trannies, but it there an easy way to know?

 

Bruce

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Bruce,

 

You might recall we've visited the subject of your OPTs a number of times.  So, yes, we could probably go back to that old link you provided earlier and have a look at the color coding on the secondary winding of the transformer.

 

If you'd like to compare them to my Electra-Print, we can do that too.  Tell you what:  I'll have a look at the inside shot you provided earlier in this thread, and tell you what to look for.  Or, have a look at the picture of these recently repaired and re-capped Moondogs.  Do you know where the secondary winding combinations are?  

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Hebe, that means I'll ha e to turn them off and open one up... I'll get to that, or find a pic of the inside of one I've made. Thanks Erik., it's not really important. As yoh said, either one is good, and I'm listening as I type this.

 

Bruce

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So, Bruce....

 

Have a look at Blackbirds pictured just above. The leads for the secondary impedance winding taps are just to the left of the filter choke.  All of the color codes seen there are used by Electra-Print.  They are the same codes that are in the manual I have for my Moondogs.

 

MagneQuest has always had a brown lead as one of those (Electra-Print Does not).  Checking your link, I can make out that brown lead in the picture you posted.  If you like, I'll tear open my Moondogs and take a picture of mine, although the entire inside is different.  I used very little of the construction manual, and built primarily from the schematic so I could make direct connections.

 

The transformers I have on my amps, right now, are from Electra-Print.  

 

Take off your OPTs if you want.  Undo the B+ connection in red, and the blue one to the 2a3 plate, and then the others, including common and positive on the speaker jacks.  Expose them so they are all clearly visible.  Then go to the MagneQuest site and refer to output connection combinations for that transformer, and you should find a match.  Pretty elementary detective work (wink)

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39 minutes ago, Marvel said:

Hebe, that means I'll ha e to turn them off and open one up... I'll get to that, or find a pic of the inside of one I've made. Thanks Erik., it's not really important. As yoh said, either one is good, and I'm listening as I type this.

 

Bruce

Right, however, it's still obviously important.  I have a ton of work to do on another person't Laurel IIs, but I will take my Moondog OPTs apart if you want.  It's busy work for me, and I can do it fairly quickly and post every single shot here on the forum.  I would just rather try to get this other gentleman's amps back to him as soon as I can.  I put aside three other build projects so I could fix these for him.  I will post a shot of the giant MQ trannies compared to my Moondogs.  Honestly, it could be used for a boat anchor!

 

I suppose I feel now that it's important to me, not just you, to confirm the identity of your transformers.  Sheesh, that was a long time ago.  I offered to look them over.  I've never charged anything for work, including an amplifier someone asked me to fix that the designer himself wouldn't work on -- after it had caught on fire.  That was a good bit of work, but it was done for a friend, and so very much worth the effort.  A good guy.

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Erik, thanks for the information. I've got a bit of other work on my plate too, so it might be a couple of weeks before I can pull one out to look. Please , don't feel obligated.

 

Magnequest now only has a Facebook front end for the company, which doesn't seem to have muct activity. Or their old pages on blogspot, which is even less active. They still do business, for sure, but they aren't as accessible as before.

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