Mcintosh 20 w-2 and ae-2a questions about adapters, and marantz model one.

[dsx123]

Hi, long time lurker on audiokarma, have gotten a ton of useful info from various posts on here.

I recently acquired a couple pieces of equipment. a couple of them I have always wanted, and kind of cant believe i have. ( especially the marantz model one)

With regards to the 20- w2 amp. There are a number of different adapters that came with it, that plug in kind of like tubes. Its kind of a cool design/ way to make expansions. there are a few, that i under stand what they do, like the one to add the speaker outs, and the one for the rca input. there are a few that i dont understand however. The three cans on the left in the photo, the two silver and the clear plastic one. I am wondering if anyone knows how these work?

My plan is to recap and use this amp.

and with regards to the ae-2a, one was marked that it works only with a 20-w2 and one says only with a 50-w2. Why would this be? also, could they be used with an mc30? I also got a mc c4, that says it can be used with the mc30. could it also be used with the 20w-2?

and finally, I ended up getting a set of marantz model ones, but they do not have the power supply or cable. If i understand correctly, these can be powered off a model 8. How would that work, and are there plans for the cables to do so? or what is the plug on the back of the model one, I am thinking of building a cable for it. another thought would be to try to build a custom power supply for it, but i feel like that may be complex.

Any feedback and/ or info will be much appreciated.
I am excited to have these. I feel like they are a part of audio history, and I am there caretaker, rather then owner.

 

[dsx123]

Well i did some research, and figured out the purpose of the silver input transformer. what kind of sources would have low output enough to necessitate the transformer? and I am still unclear what the clear can is for.

another question i thought of. has anyone heard one of these? how do they compare sonically with models like the mc30/ mc225?

 

[gadget73]

Usually that sort of transformer is used to take a balanced input and make it work on an amplifier or preamp with an unbalanced circuit. Not sure the specifics on this one though. They are also sometimes used for impedance matching of microphones. LoZ to a HiZ input or vise-versa.

Can you post a clear picture of what exactly the tag on the clear transformer says? Enough is cut off that I can't figure it out.

 

[dsx123]

Ok, here are some better pics of the parts in question. now that I look at them again, it seems two of them have a spot on the top for a tube. I am excited to get this amp going, I always have wondered how these early amps sound.

 

[gadget73]

best I can find is this:

McIntosh Double Shielded Input Transformer Model ATI-1 for 50W-2 and 20W-2 Amps. The ratings are 30-50, 250, 600 ohm.

sounds like its used to convert a low impedance source to the high impedance that the amp runs at. The low ohm stuff would be balanced line or as a booster amp from another distributed sound rig. 250 and 600 ohm were common for that, similar to 25v and 70v PA systems in the slightly more modern era.

 

[kcin]

and finally, I ended up getting a set of marantz model ones, but they do not have the power supply or cable. If i understand correctly, these can be powered off a model 8. How would that work, and are there plans for the cables to do so? or what is the plug on the back of the model one, I am thinking of building a cable for it. another thought would be to try to build a custom power supply for it, but i feel like that may be complex.

The Marantz model 1's or Consolettes have their own individual power supply which connect through a Jones plug to the preamps. The preamps are not designed to be attached to a model 8 or any other amplifier for power. These PS come up rarely- I have seen people design their own where the PS is missing- plans to do so would be derived from the schematics of the cosolettes.

 

[dsx123]

The Marantz model 1's or Consolettes have their own individual power supply which connect through a Jones plug to the preamps. The preamps are not designed to be attached to a model 8 or any other amplifier for power. These PS come up rarely- I have seen people design their own where the PS is missing- plans to do so would be derived from the schematics of the cosolettes.

Interesting. for some reason I always thought they could piggy back off the model 8. or maybe that was the model 2 I was thinking about. Looks like I will have a project coming up. Will have to take a look at the schematic.

 

[dsx123]

The Marantz model 1's or Consolettes have their own individual power supply which connect through a Jones plug to the preamps. The preamps are not designed to be attached to a model 8 or any other amplifier for power. These PS come up rarely- I have seen people design their own where the PS is missing- plans to do so would be derived from the schematics of the cosolettes.

I think the 8 has some kind of preamp power out, although it probably doesnt work with a set of ones. I wonder if something like a mcintosh mc30 would be able to power them? I also have an eico mono block that has a power out for a pre, as well as a mcintosh 20 -w2. Its too bad the didnt standardize the power outs for preamps that got power from the power amp.

 

[gadget73]

The 8 and early 8b does have a preamp power outlet but thats about all I can tell you about them. I have no idea what it was intended to power, but I can say there is only one jack.

The model 1 being mono, i'd expect it to pair with probably a Marantz 2 power amp.

 

[kcin]

@ gadget73 :"The 8 and early 8b does have a preamp power outlet but thats about all I can tell you about them. I have no idea what it was intended to power, but I can say there is only one jack.

The model 1 being mono, i'd expect it to pair with probably a Marantz 2 power amp."

Gadget is correct that Marantz model 8 and very early 8b's had an octal socket - this was probably to power early preamps of the era including Marantz's predecessor to the Consolettes. You should measure the octal but I recall its pretty standard : pin 1 is ground , pin 2 is 12v and pin 3 is about 465v.

The Consolette uses a series string for the heaters at 18.9v and the B+ is about 320v . The consolettes are very valuable and desirable I would not go modifiying them because you don't have what you need. I would build up my own PS. As I mentioned before- the schematic is your friend.

Btw I have a pair of Consolettes and a pair of Model 2's and the model 2's do not have any provision for powering the Consolettes.

 

[gadget73]

Btw I have a pair of Consolettes and a pair of Model 2's and the model 2's do not have any provision for powering the Consolettes.

interesting. Whats the socket on the top for then? Thats usually what I've seen for preamp power, but I know nothing about either other than knowing it exists.

**edit** nevermind, I'm blind. The EL34 tubes are not installed.

 

[dsx123]

@ gadget73 :"The 8 and early 8b does have a preamp power outlet but thats about all I can tell you about them. I have no idea what it was intended to power, but I can say there is only one jack.

The model 1 being mono, i'd expect it to pair with probably a Marantz 2 power amp."

Gadget is correct that Marantz model 8 and very early 8b's had an octal socket - this was probably to power early preamps of the era including Marantz's predecessor to the Consolettes. You should measure the octal but I recall its pretty standard : pin 1 is ground , pin 2 is 12v and pin 3 is about 465v.

The Consolette uses a series string for the heaters at 18.9v and the B+ is about 320v . The consolettes are very valuable and desirable I would not go modifiying them because you don't have what you need. I would build up my own PS. As I mentioned before- the schematic is your friend.

Btw I have a pair of Consolettes and a pair of Model 2's and the model 2's do not have any provision for powering the Consolettes.

I think you are correct, I for sure shouldn't modify them. I think I am going to work on building a power supply for them. I have seen it done, and it didn't look too complex. The model twos are also on my bucket list of gear I would love to own someday. I wish I had saved and bought a set 20 years ago, when they were still found a decent amount on fleaBay. I actually have one model two, but it is a mess, and it has a replacement transformer. That is a whole other mess I need to sort out someday, but first i think i will try and get the models ones running.

Thanks for all the feedback on here. A few of the people that commented have posts I have read in the past that was super informative.