The Menace

[thrice]

Thanks for the kind words guys, it was very much a labor of love. The only bummer to come out of it is that my shelf space is simply not tall enough to allow me to put the wood accent pieces on that I originally wanted to. As it is there's only about 1/4" of clearance for the power supply (at the large choke) so I'm going to have to forgo that dream. I still might try to do something with the amp section since it isn't nearly as tall but right now I don't know how I feel about the two looking dissimilar.

*cough*buildanewrack*cough*

[n_maher]

*cough*buildanewrack*cough*

I'll get right on that in all the spare time that I have coming up this summer...

What is more likely is that there'd be a V2 of the power supply that used a different chassis since there's no earthly reason to use a 4" tall one like I did, I just had it laying around. But again, that's just not going to happen any time soon.

[swt61]

Knowing you Nate you'll have sold it long before you'd get to adding the wood trim anyway.

I for one hope you keep and enjoy that beautiful monster for a long time to come. It's quite an incredible build!

[n_maher]

Knowing you Nate you'll have sold it long before you'd get to adding the wood trim anyway.

Nah, if that was going to happen I would have done it at CanJam so I didn't have to ship the thing home! But seriously, knowing what I have into it for parts and time I really couldn't charge enough since all I'd do is build another.

I for one hope you keep and enjoy that beautiful monster for a long time to come. It's quite an incredible build!

Me too, I need to roll in a different input tube, the RCA that I had in there last night was kind of muffled and congested sounding. I greatly preferred the 5692 and the Sylvania 6SN7's that I've heard so far.

And the parts for my 7N7 adapters should be arriving this week so I've got that to look forward to.

[guzziguy]

Which one though, Art Carney, Jack Lemmon or Tony Randall?

Looks great Nate. I hope I get a chance to hear it someday.

Whichever one of them that could solder, of course!

And the parts for my 7N7 adapters should be arriving this week so I've got that to look forward to.

The tall bottle Sylvania 7N7 is one of my two favorite gain tubes in the SP Extreme. Just be sure to get a Sylvania tall bottle. Somehow I got a Sovtek tall bottle 7N7. It's not bad but not close to the Sylvania.

I'll get right on that in all the spare time that I have coming up this summer...

What is more likely is that there'd be a V2 of the power supply that used a different chassis since there's no earthly reason to use a 4" tall one like I did, I just had it laying around. But again, that's just not going to happen any time soon.

Yet you have time to make 7N7 adapters.

I really like the look of the 4" tall cases. It gives the Menace the proper proportions and I definitely think that the PS and amp should have the same size cases, unless you are going to stack them. Then you could get away with a thinner case. Of course, YTMV (your taste might vary).

[luvdunhill]

once you get the 7n7 up on adapters, they will be pretty tall, assuming you make adapters the same way I do.. then again, all my adapters have plate caps on them... don't forget about the 7af7, and perhaps it's time to think about a 12.6v heater option for your psu... this results in............

more tubes!

[n_maher]

once you get the 7n7 up on adapters, they will be pretty tall, assuming you make adapters the same way I do.. then again, all my adapters have plate caps on them... don't forget about the 7af7, and perhaps it's time to think about a 12.6v heater option for your psu... this results in............

more tubes!

Any pictures or details of the adapters that you've built? I'm more than just a little curious since all I was planning to was a direct pin to pin wiring of the loctal socket to the octal base.

And there won't be any 12.6V option, it is what it is at this point and it's not going to undergo any substantial changes in the foreseeable future.

[luvdunhill]

ah, 12.6V is only a single switch away! And so many more (cheaper) tube options await you, not to mention less current draw.

[img width=150 height=113 alt=P1010236]http://www.head-case.org/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=1494&g2_serialNumber=2&g2_GALLERYSID=245ffaedcdd434c3e031cadbc1e3669e

[n_maher]

ah, 12.6V is only a single switch away! And so many more (cheaper) tube options await you, not to mention less current draw.

Current draw really isn't an issue. Right now the input tube is drawing .6A of a possible 4A on that winding, but I know what you're saying. And it wouldn't quite be a single switch away as far as I can tell. The filaments are biased to B+ so I'm sure you could just simply switch in the 12.6V supply in place of the 6.3V without a pretty complicated switch. Granted, I haven't given it any thought so I could be over complicating the scenario but that's reason enough to pretty much stop thinking about it at this point. I want less building, more listening for a while.

[luvdunhill]

the adapters are pretty easy to make. Hardest part in my case was drilling a hole in the base for the top cap, as those bases are pretty fragile when drilling at that angle. You won't have to worry about this. I like to use bases and sockets that fit inside each other, then once the adapter is tested then I can secure the two together with an appropriate adhesive. I've also found that using PCB sockets work better that the loop style, as they are more compact when pushing the socket into the base. Just make sure you use proper temperature (and voltage) rated wire and you'll be fine.

[n_maher]

Schematic Time (click for larger versions if you have trouble reading these)

Amp

PS

I'll try to put together some thoughts on the build for inclusion with this but as you can see it's actually a pretty simple circuit with a low parts count. The only small correction that needs to be done is that the transformer is actually the BFT-1B, they don't make the 1A anymore but they are essentially the same so I'm not going to worry about it for now. And it should go without saying but I'll say it anyway, there are lots of options that individuals can choose. First and foremost the power supply could be something entirely different and might be made simple enough so that the entire thing could fit in one chassis. Along those lines there's nothing forcing anyone to use the giant motor-run caps that I did, the output caps can be whatever your heart/wallet desires. But what's shown is exactly what I built and the results are more than enough to convince me that I made some good choices and that Pete gave some great advice.

[kevin gilmore]

Nate, why did you have to go and publish the schematics?

Now ray will finally be able to finish his A10...

(not a chance)

[n_maher]

Nate, why did you have to go and publish the schematics?

Now ray will finally be able to finish his A10...

(not a chance)

:rofl:

[justin]

I wonder if anyone will actually build it with a 50V cap for C3?

[kevin gilmore]

someone is paying attention...

[n_maher]

I wonder if anyone will actually build it with a 50V cap for C3?

Whoops, that's supposed to be the same 10uF/400V cap used for C4. Clearly not 50V. Thanks for the catch, Justin.

[spritzer]

I wonder if anyone will actually build it with a 50V cap for C3?

Ray perhaps...

[fierce_freak]

lol, leave it that way just for him

[Fitz]

Ray perhaps...

[n_maher]

Schematic corrected and updated. May require clearing of cookies to see the new version since I did a direct replacement at the host so that the links would stay the same.

[luvdunhill]

I'm investigating a product right now called pyrosealant.

And we were thinking the same thing with the silicon caulking. There's no room for washers since anything that has an I.D. of 1-1/2" is going to have a huge O.D. and not fit in the hole. I'm working on some hand filing to slightly enlarge the hole that I drilled but I definitely want a physical layer of separation between the socket and the bare metal edge of the hole.

nate, what did you end up using here? I need some sort of silicon adhesive for securing some capacitors and what not. It needs to be insulating as well, as the caps have metal casings. I remember a thread somewhere about silicon adhesive... I looked at Home Despot yesterday and really couldn't find much to fit the bill ...

[n_maher]

nate, what did you end up using here?

I used red RTV silicone gasket material, but I'm not sure that's what would work best for your application. Are you trying to secure caps together or secure caps to a chassis? If it's the former, this should work but I'd first put o-rings around the caps to act as spacers and then fill the void with whatever adhesive you choose. That way you're not at all concerned with the compressive strength or elasticity of the adhesive. As for sources try automotive-type (Pepboys, etc) stores, it was in the automotive section of my local hardware store. If it's the latter I wouldn't use any kind of adhesive and would look for a mechanical connection like Pete, Kevin and Naaman suggested.

[luvdunhill]

Nate:

Did you ever post the other psu schematic? I'd rather like to take a look at it, if possible.

[n_maher]

Nate:

Did you ever post the other psu schematic? I'd rather like to take a look at it, if possible.

It's an untested, unfinished design so I'd rather not float it out there for public consumption. I'll host it somewhere and shoot you a PM.

[n_maher]

So this seemed as good a place as any to post the final details of this. Might as well have all my insanity in one convenient location (for now).

Earlier in the year I sold the Menace. Sad day, for sure, but one that ultimately became more and more necessary as Lily started to take over more and more of the space that I formerly called audio-home. Let's face it, when push comes to shove she's small but deceptively powerful. Anyway, as I found myself now headphone ampless I started digging through drawers in my diy workshop looking to see if I had enough parts to build a power supply for my long out of service Millett Hybrid. What I found was that in typical Nate fashion I'd acquired an insane degree of spare parts for the Menace. So with a little help from Ari (nikongod) we tweaked an existing design that used the same tube compliment by had a transformer coupled output and created what I named the MenaceTC Lite. Why Lite? Well, two reasons, one it weighs less than the original Menace due largely to the fact that it uses a SS power supply and two, the real MenaceTC is still sitting in 4 more boxes and is my "keep me sane this winter" project. When I get a chance I'll try to finish up the Lite schematic and post it, it's a deceptively simple looking beast but is not without it's share of neat tricks. For one thing it's a choke filtered power supply rather than the typical throw a huge cap in there style, it uses LEDs to bias the input tube along with some other trickery that Ari will have to explain. But this is getting long, so without further adieu here she is in mostly finished garb.

External Shots

Power Supply Side

Amp Side

Low Front

Back

"Dusty's Detail" (custom black SS washers)

Upskirt Pron

Overview

Audio Bits

Ground Bar

Initial listening impressions are, well, worthless so far but I'm about to go remedy that. I have the filaments floating right now and eventually I'll do something similar to what I did on the original Menace and reference them to ground. The amp does have just a touch of hum, hardly worth noting, and I believe that once the filament work is done that'll be a thing of the past. For those in the greater NYC area I'll have the amp with me this weekend.