Show off your 2ch system

[dtel]

never thought of that, it's a unusual perspective.

I specialize in unusual perspectives. [Y]

[dtel]

I can't remember if I posted in this thread or not, so here is my system as it is now. Except the Super Baldwin amp in the pic is out and the Korneff 45 is in. I switch these two in and out every once in awhile but, the Korneff 45 is my refrence amp and always will be!!!

Jay

That is some cool looking tape machines, I use to have an old Akai, it looked like a toy compared to those.

[dtel]

The only place these beasts will fit is in my garage so here is DIY MWM bottom with DIY 555 bin and JBL 2360A horns with EV DH1A drivers .Center is a Peavey FH-1 with LSI top.

Well..........how's it sounding ? []

[erik2A3]

Speaking of Baldwins.........

I've spent the past two weeks completely rewiring one I'm sending to an old friend. It's essential exterior architecture remains the same, but the plumbing needed a thorough going over, including replacing a few of its antique carbon comp resistors that had drifted, installation of brand new octal sockets for its dual rectifiers and compliment of four 6L6 outputs, new cathode bypass and coupling capacitors -- and lastly and without a doubt most importantly, a single star ground configuration. Power supply, input/driver/phase inverter stages, and output stages have all been separated, with the stereo channel signal grounds separated via a 10 ohm resistor in a very unique position (not the common Dynaco RCA ground tab to ground connection, but derived from that).

The Baldwin was designed to use the chassis as a ground plane, with common ground connections at the nearest convenient place on the chassis. While this works, I was impressed with how much of an improvement was gained in terms of the drastic drop in background/ground loop noise through 104dB speakers afforded by star grounding (which always seems to help).

It's been a long while since I did anything at all with this amp, but it is playing music in a way that's pretty amazing. There are several amps I could live with on a daily basis, and this is without a doubt one of them. The La Scalas are in a very large listening space -- the entire first floor of our house, and as much as I like the SEOTL I've mentioned many times in the past, it simply was completely unable to fill that space well without running out of steam. That amp is only a bit over a single watt per channel, and does just fine in our upstairs combined HT/listening room. For a larger space, the horsepower of an amp like the Baldwin makes a really big difference. I'd forgotten what a great amp this is, and even better with these latest updates and modifications.

I had also experimented with bypassing the cathode resistor of the first stage, which among other things offers a bit of gain, but found the balance in frequency response tilted rather than even from top to bottom. Bypassing is one of those things easy to try, and easy to do away with if needed. While mentioning this, I should add that I also removed the old (and on this amp severely deteriorated 50k input potentiometers, and replaced them with a fixed value 50K (actually two 100K ohms in parallel) metal film resistor from grid to ground. it's also kind of an eye opener in terms of how new metal film resistors can sort of 'wake up' an amp, though I would say too much of that can be, in a subjective sense, maybe not such a good thing. Input stage cathode resistors also needed to be replaced. All filament wiring was also replaced with new fresh, undamaged (just from age) wire.

Wonderful amp, and I'm on the look out for another for a similarly done complete restoration. All the above work was done minus a schematic, but I finally was able to get my hands on one which enabled me to check operating voltages, etc.

Happy, happy! erik

[jcmusic]

...yes the two decks are awesome!!! They are both modded to take the signal directly from the playback head and send it to an external tubed tape pre amp!!! Really sweet stuff!!!

Is that an Otari on the right side? Built like tanks!

Bruce

Hi Bruce,

Yes that is an Otari MX5050 BII-2.

Jay

[jcmusic]

Jay's system sounds incredible! I had the pleasure of listening to "Little Hatch" from his Tape Project collection.......... pure, clean Nirvana!

Hey Jeff,

How are you and the Mrs.? I trust all is well! How is that Sony doing? I hope you are still enjoying it!

Jay

[jcmusic]

I can't remember if I posted in this thread or not, so here is my system as it is now. Except the Super Baldwin amp in the pic is out and the Korneff 45 is in. I switch these two in and out every once in awhile but, the Korneff 45 is my refrence amp and always will be!!!

Jay

That is some cool looking tape machines, I use to have an old Akai, it looked like a toy compared to those.

Dtel,

The next time you are near New Orleans let me know so we can get together and you can come by and give a listen!!!

Jay

[erik2A3]

Forgot to mention:

The two vertical cathode resistors for the output stage have been replaced with modern aluminum types mounted directly to the chassis, but by way of 1/2 aluminum stand-offs. The original two, one of which seemed to have led a stressful, possibly slightly overheated life, cracked when I very slightly moved the solder terminal lug when installing a new length of wire to it. It was also 10 ohms below its stated value, which isn't drastic. It was the damage that was unacceptable.

An important aspect of grounding, which some here may know (though I've known a number of techs who haven't) is that it CAN help to ground the center tap of the power transformer directly to the common (ground) connection of the first filter capacitor -- and then from there, not to daisy chain filter caps, but connect them according to their stage in power distribution of the rest of the circuit, individually to an uninsulated ground buss. I made the ground buss using #14 wire, toward one side of the chassis near the input jacks. All power, input, and output stages were connected individually for each channel to this buss, and from there, on the Baldwin, a single wire is run to the chassis on the side of the amp with heavy wire, and connected at the point with a ring terminal and star washers.

The new owner of this amp had purchased and sent to me another quad of Winged C 6L6s, which sound spectacular. Erik

[erik2A3]

Let me quickly add while on this subject that those of you with Baldwin amps that don't have some of the changes I made on the one I have here does NOT mean that yours is not up to snuff. If it's working and sounding good to you that's all that matters. I am extremely picky, pickier than most, about any extra noise from electronics when paired with high efficiency speakers, and will continue to search and experiment to get at the root of an issue. I did the same thing with my Transcendent amps, and mentioned some things that helped there, too.

I spent two weeks on these modifications, and could never afford to pay someone for that amount of labor and reworking -- on top of that, I love the challenge! My wife often says I wouldn't be happy if everything with my electronics was working exactly as it should. I recently also bought an as-new PrimaLuna preamp, but was unhappy with the value of potentiometer used, as well as part of how it was grounded (which caused noise, amd which I was able to completely remedy). That's just me. I'll get something and almost immediately try to re-enginner aspects I think might be improved -- which doesn't always happen. Erik

[fini]

Erik, sounds like a fun project! It's empowering to get to the bottom of a problem by just jumping in there and trying things. Good for you!!

[kg4guy]

The only place these beasts will fit is in my garage so here is DIY MWM bottom with DIY 555 bin and JBL 2360A horns with EV DH1A drivers .Center is a Peavey FH-1 with LSI top.

Well..........how's it sounding ?

Well I'm still amazed the bass is amazing in these cabinets they are big but simple and the JBL horns give a very big live sound to match them. I am still going to experiment with the mid bass cabinet I have a Peavey MB-2 I will try in place of the DIY 555 but I wonder what the Klipsch mid bass sounds like and also curious if they sell just those cabinets?[^o)]

[dtel]

also curious if they sell just those cabinets?

I have no idea ?

I like that big horn your using, I think what i like most about that which is similar to ours is how big it sounds. Any speaker can go loud but that big open effortless sound is hard to beat. It can easily fill a room or big open area without sounding like it's being pushed. [Y]

Mark 1101 is using a midbass horn, I would bet it sounds great.

[erik2A3]

Hey, Gregg:

Thanks for taking this in the right light, and for the encouragement.

Still working on this thing, but waiting for a couple of more parts, I have found connections that were crimped but not soldered that date from when the amp was first put together. So proceed with some discrimination when rebuilding and rewiring something like this.

Discovering how hot this amp actually get inside -- there is a power supply bleeder circuit with large power resistors that get pretty warm, plus the output stage cathode resistors, make me think it might be, to one's liking of course, to not use a bottom plate. I have the large rubber feet mounted on the flange, by way of a larger fender washer between the flange an the top of the foot. And then a cap nut to finish it above.

I don't think there is anyone that is able to finish beatup chassis and transformer bells like Will (his powder coater needs to be credited too, without a doubt!), but this amp really came to life with the work done inside. Good grief it's a nice sounding amp, too. There is something kind of SET-like about it, but with an enormous scale and sort of jump factor that makes listening really fun. The improved grounding scheme makes music jump out of silence, with incredible dynamics.

The exterior view is the same, except for my addition of the amber pilot light that was installed where the power switch used to be, and the switch moved to the side, with the fuse also relocated.

[erik2A3]

....I'll share a picture one of these days. I'm on the Mac and all my images are on the other computer. Erik

[Daddy Dee]

Just one quick pic here. From the front plate you can see that this amp is was Will Vincent rebuild from some years ago. I had one of Will's Baldwins, along with a pair of his work of art Mark III's. I was impressed with Will's redemption of those old organ amps in the first unit I had. Think that amp had the best bass dynamics I'd heard in any amp. Pretty. Awesome. One has to remember though, these amps were new some 55 years ago, so they do take some TLC over time.

l'm most fortunate to be on the receiving end of this project. Erik has done a ton of work here with some creative improvements to the circuit making it quieter than before.

The tubes are a quad of Winged C 6L6 along with a pair of JJ ECC 83 / 12ax7

I've had an attack of amnesia about the rectifier tubes.

Kudos Erik! as always great work.

Thanks for outlining the specifics on the project.

edit: the dual rectifiers are 5u4 type tubes. btw, the amber pilot light. which Erik added, looks perfectly retro oem on this amplifier. IMO

[Marvel]

I love it! My ST-70 is pretty well stripped right now. I had a Curcio front end I put in about six years ago, but I wasn't totally satisfied with it. I got a tubes4hifi board to try next, but I am thinking of making changes to use some 6L6 output tubes.

Bruce

[erik2A3]

Dee

Thanks, that saves me some time. It's very close to being done now. Erik

[erik2A3]

Bruce

The welborne labs upgrade board for the St70 is apparently very good. I Haven't heard it myself, but I believe Allen Kimmel, who also influenced aspects of the Moondogs, had a hand in the dynaco upgrade (for which a larger power transformer is also available -- you know how hot the stock trannie runs....). The dual rectifiers for the Baldwin are the 5U4 type.

[Marvel]

Erik,

The Welborne Labs front end costs too much! $320 without the tubes. I got mine from tubes4hifi, and it is a nice board. I'm using the 12aut version, since I don't need the higher gain.

http://www.tubes4hifi.com/ST70.htm

The power tranny is from Triode Electronics... a heavy piece of iron, that runs cooler.

http://store.triodestore.com/mq060.html

I'm tempted to move it all to a larger chassis.

Bruce

[Y] all links open in new window

[erik2A3]

Bruce

True enough, it 's not inexpensive. I had been wondering if Welborne sources the power transformer from Triode Electonics. I have to say that a bit more power for our La scalas in this big area made a difference. The Baldwin does not have they same low end control of the OTL amplifier, but it is not too bad either, just kind of different. I need to get a good sub for the LS, though.

I think/ hope The Baldwin above is going to be a very nice amp for Dee's Heresy/sub system. It's a great combination, and has been a source of inspiration for all the work I did on it. I could have had it running in about 30 minutes, but there is so much more that went into its revival beyond making it 'just work.'. For a SET lover like me, the 6l6 in push pull is like a 2a3 or 45 on steroids; all the air and presence at 10 X the power. And of course just an expression of my own response to it.

I was actually gping to turn the amp into a PP 2a3 I had been working on, but am glad I didn't. Replacing the riveted octal sockets wasn't exactly fun, but grinding the rivets down with a rotary tool and then punching them out sure made it easier. My dad was able to translate some of the color coding on the mica caps that are used in a rather uncommon to me ( to him it wasn't) plate-shunt position, which are probsbly there to filter RF. I wish my paragraph breaks would actually show up when I post! Erik