Erik Mandaville Posted June 21, 2004 Share Posted June 21, 2004 Thanks, Neo. I'll take a schematic, a potter's wheel, sculpture tools -- that sort of stuff anyday to computer technology. It just doesn't stick well with me. People have different abilities and talents, but computers for me can be a struggle. Actually, I have many to thank on this forum for learning how to post manipulate and post digital images, which is something I never knew how to do before I came to this site. I have learned TONS here! Quote Link to comment Share on other sites More sharing options...
Deang Posted June 21, 2004 Share Posted June 21, 2004 So who's going to buy my QUADs so I can try the Moondogs? $1575.00 Quote Link to comment Share on other sites More sharing options...
Dale W Posted June 21, 2004 Share Posted June 21, 2004 Thanks for the heads up guy But i think i'll take a stab at the 300b first then switch to the 2A3 if i feel the added power is not needed or if the 300b is missing whats i'm looking for . Quote Link to comment Share on other sites More sharing options...
Piranha Posted June 21, 2004 Share Posted June 21, 2004 ---------------- On 6/21/2004 9:42:22 PM AK-4 wrote: So who's going to buy my QUADs so I can try the Moondogs? $1575.00---------------- Are you serious Dean? I know you would buy VRD's before Moondogs. Quote Link to comment Share on other sites More sharing options...
Deang Posted June 22, 2004 Share Posted June 22, 2004 I told Paul I really wanted to sell the QUADs to try the VRD's -- but my VRD's won't be ready for a while, so I have time to play. The Moondogs are an easy sell, so I could at least try them for a little while. I want to know more about what Rick saw. The connection from the driver to the board, under the cathode wires, to the coupling cap, to another board to the cathode of the 2A3, is that the normal way these are wired? why? Quote Link to comment Share on other sites More sharing options...
JohnWhite Posted June 22, 2004 Share Posted June 22, 2004 Now those are some nice looking amps. Of course after seeing them I took a look at Welborne Labs and find that the Moondog kits are no longer being sold Ah well, I guess I will just have to squirrel away some dough and snag a pair off Audiogon sometime. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted June 22, 2004 Share Posted June 22, 2004 Dean, That one is wired the same way I guess it is normal. My question is why the cap is not wired point to point in a more "economical" manner? Ron Welborne must have had a reason, but what? Rick Quote Link to comment Share on other sites More sharing options...
ben. Posted June 22, 2004 Share Posted June 22, 2004 What's the story with the AA batteries? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 22, 2004 Share Posted June 22, 2004 That is a mod to run DC on the heaters rather then AC it reduces hum. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 23, 2004 Share Posted June 23, 2004 Just a slight correction: Some people have experimented with using two AA batteries to bias the 6SN7s, which is what I think was being done in the case of the above Moondog. This amp, like virtually all Moondogs, is wired for AC on the 2A3 filaments, which you can see connected to the hum balance control toward the center of the amp. The two blue electrolytic capacitors are the filter caps in the DC rectifier and filter circuit for the 6SN7s. The way the high viltage filter capacitor is wired looks really strange to me. The dropping resistor looks to be installed correctly, but I'm studying this thing to find out what is going on. From what I can see, there is a twisted pair of wire from the large filter capacitor that extends over to where the RCA input jack normally is. From that area, there should be either a twisted pair (one of which is grounded)or a shielded cable going to the grid of the first 6SN7..... Binding post connections appear to be done with what looks like insulated silver wire, but I can't figure out the input connection. Also, the yellow twisted-pair AC heater supply for the rectifier (last tube on the right) should really be running along the right wall of the chassis. As is, it's really close to the first stage. One of the things I changed on my Moondogs has to do with the fact that multiple connections were often used, where just one would have sufficed. I think this was done intentionally to help provide numbered reference points on the terminal boards to help new builders. An example of this can be seen on the coupling cap between the second 6SN7 (this is the tube socket just to the right of the 2A3, which is the last tube on the left). The coupling cap could have been wired directly connected to the 2A3 grid, but instead goes to the terminal board first. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 23, 2004 Share Posted June 23, 2004 I think I may have figured this thing out: I believe the black twisted pair that's connected to the filter cap might be a B+ delay. Those twisted wires would go to a switch that's installed in the hole in the backplate normally used for the RCA jack. Depending on the actual connections, it's also possible that it's a switch to provide a bypass route across the dropping resistor. This would provide an increase of B+ to make the amp more suitable for use with the higher voltage ratings of some 2A3s, such as The KR Enterprise 2A3. If it's a standby switch, another way of doing this would have been to install a switch across the red/yellow center tap on the power transformer. I also found the input connection. It's just above the 6SN7s, where an extra hole had been drilled for it -- the same as I did on my amps to achieve the shortest possible route from the jack to the first 6SN7. Is someone contemplating a purchase of this amp? Quote Link to comment Share on other sites More sharing options...
neo33 Posted June 23, 2004 Share Posted June 23, 2004 The wirings in those Doggies look like a work of art. I wish mine can be like that. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 23, 2004 Share Posted June 23, 2004 What you say is really true, Neo. Moondogs look the same on the exterior, but the part that matters is really the inside. If you practice a little with a soldering iron, SET amps are fairly straightforward in terms of improving wiring issues. It might make for a rewarding project for you, and you have someone who can help you out if you hit a snag somewhere. If you have another amp you could use in the meantime, you could do a little rewiring of your Moondogs when you had the time. Depending on the strength of that wish of yours, a neater looking and possibly better sounding pair of Moondogs could be very possible. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 23, 2004 Share Posted June 23, 2004 Eric, I guess my memory didn't serve me well. I thought the battery mod was for the 2A3 heaters Ooops I looked and I can clearly see that the wiring does not run to the 2A3. Craig Quote Link to comment Share on other sites More sharing options...
mike stehr Posted June 23, 2004 Share Posted June 23, 2004 "If you practice a little with a soldering iron, SET amps are fairly straightforward in terms of improving wiring issues. It might make for a rewarding project for you, and you have someone who can help you out if you hit a snag somewhere." Yup! Quote Link to comment Share on other sites More sharing options...
Deang Posted June 23, 2004 Share Posted June 23, 2004 Man, that's a monster. Yikes. Quote Link to comment Share on other sites More sharing options...
jazman Posted June 23, 2004 Share Posted June 23, 2004 ---------------- On 6/23/2004 12:28:15 PM neo33 wrote: The wirings in those Doggies look like a work of art. I wish mine can be like that. ---------------- Neo, You mean to say your Moondogs don't look like this underneath.(Just kidding!) Wiring done by original builder, not me. I have not found a sufficient (performance enhancement) reason to modify his craftmanship. Klipsch out. PS. Thou shalt never make a hurried post. I'll try to clean this mess up later if I can. Quote Link to comment Share on other sites More sharing options...
Deang Posted June 23, 2004 Share Posted June 23, 2004 I don't know a thing about those amps as far as the impact of the various parts on the sound -- but has anyone ever tried replacing the Solens with something a little better? Quote Link to comment Share on other sites More sharing options...
3dzapper Posted June 23, 2004 Share Posted June 23, 2004 Again Erik on Edmund's Dog, The coupling cap is wired to the lug back to the grid. Puting that lead under the A/C filiment wires can only lead to noise induction. Plus it allows two more chances for a cold solder joint in the critical signal path. Edmund, your Dog looks like a pedigree. Rick Quote Link to comment Share on other sites More sharing options...
neo33 Posted June 24, 2004 Share Posted June 24, 2004 "Wiring done by original builder, not me. I have not found a sufficient (performance enhancement) reason to modify his craftmanship." Dang, your Doggies have nice guts, Edmond! Quote Link to comment Share on other sites More sharing options...
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