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Warning About The Singlepower Extreme - Owners Please Read - Page 12

post #166 of 407
Thread Starter 
Quote:
Originally Posted by kevin gilmore View Post
So i was nice enough to offer moonboy the services of nate maher who was stupid
enough to accept. So nate was nice enough to offer skylab my services and i was
stupid enough to accept. OK, i'm done with this
Instant Karma's gonna get you Kevin.

Glad to hear that another Extreme is now ready to live a healthy, happy life.
post #167 of 407
Quote:
Originally Posted by The Monkey View Post
I think that actually looks pretty cool.
Me too! I think the Eletra-print transformers look nice on the Extreme. And they have the added advantage of working right
post #168 of 407
Nice work there Paul, hope to see the rest of your journey in pictures. Good luck.
post #169 of 407
Thread Starter 
Quote:
Originally Posted by The Monkey View Post
I think that actually looks pretty cool.
I agree. In the end I do somewhat marvel at what the "real" transformer looks like when it's large enough to supply the power required.

I read, and I think once even saw, a balanced Extreme. I wish I knew who the owner was, that amp has to be in seriously bad shape.
post #170 of 407
Wow, it looks a lot better now.
post #171 of 407
Wasn't it markmaxx? He has a Supra Extreme XLR.
post #172 of 407
Quote:
Originally Posted by mourip View Post
Kevin. What is the value of those wire wound resistors that drop the filament back to ~6.3v?
Depends on the individual unit, the size of the wires from the diode
bridge, the diode bridge itself... Anywhere from 0 to .15 ohms.

Measure first. Probably ok at 0.

Measure at the tubes!

3 down, just 400 more to go...
post #173 of 407
Quote:
Originally Posted by mrarroyo View Post
Nice work there Paul, hope to see the rest of your journey in pictures. Good luck.
Thanks. It was tricky doing all of that drilling and grinding over that powercoat black finish. I had to mother it along while my patient friend did his work. Luckily it turned out well...
post #174 of 407
Quote:
Originally Posted by kevin gilmore View Post
Depends on the individual unit, the size of the wires from the diode
bridge, the diode bridge itself... Anywhere from 0 to .15 ohms.

Measure first. Probably ok at 0.

Measure at the tubes!

3 down, just 400 more to go...
Thanks Kevin. I will wire it up and see what I get and then tweak from there. I have a pretty good stash of old low value wirewound resistors to draw from...

post #175 of 407

Different Extreme Drummer

I went a different route.



hammond/182e117/toroidal-transformer


The original Hamond transformer bobbin tranny did not show stress, according to tech. Since it was designed as a filament transformer, we decided to leave it be and supply only the filaments properly wired with it and to find a torroid that fits internally in the case to supply independent plate voltage. I was able to find a deal on the Hammond over 1/2 the price of catalog, so I thought what the heck--let's give it a try. I opted not to go blue, as well.

The torroid is 3.0" diameter, 1.6" tall. It fits in the Extreme case. The pics show it wired properly.

The data show 6.3V from Hammond and 180V out of the torroid. The external form factor is unchanged, only a single smallish bolt holds the torroid to case bottom, not visible unless unit is upside down.

Well, I turned it on and plugged in the the neural net distortion meter, cochlea-driven, pinna-modulated, HD600/cardas aided. RCA 6AS7G and WE 396A (ECC1 adapter). FYI.

The preponderant bass is gone, the unit is more transparent sounding, better balance. Still great bass, just not a 'tipped-down' sound anymore. Maybe I was hearing a bit of sag before--though it was not bad, just better now TME.

Notable is that the tranny case is now only warmish to touch. I estimate now 110 deg F, which is cool, I think. Before, it passed the the manly pinky test, now it could pass the Hot Lips Hoolihan test.

Listening volume out of Zapped Zahlou DAC into amp is 9 o'clock. Tube hiss sets in at 1-ish. ZERO HUM all the way up the dial, just like before. So it's true what they say about torroids not humming, I suppose.

What I call the OTL character (or others may believe it is the large cap character) is still there, and this is not bad, just different than some of the OT amps I own, like my favorites pictured below. I still own my Ear Max Pro, btw, still smitten by the warm clarity and goodness of prime hot gl-ass with pinched waists from Germany and Holland. Talk about cool running and tiny triode footprint. A classic.

The OTL amps I have owned are more fatigue free on over-extended loudish (85 db or so, db-A weighted, peak captured) listening, I have noted.

The extreme sounded great before, it sounds better now. I kept the external form factor, which I wanted to do, and I saved some bucks, which I also desired. I have seven or so tubed headamps (having sold around six others), and not all can live under one roof this coming (cold) winter, due to some changes I fear are coming. On the other hand, seven tube amps might be comfy on some days, when wolves start to howl. The problem is, each time I listen to these gals, I fall in love all over again with each. Clearly, I gots to get a life, and sell an amp or two. I may need to take extreme steps.

That's my story for now.

Thanks Kevin, Rob, Paul, Skylab, et al., for the great guidance. I found this particular thread the best I have experienced anywhere due to the above truly SUPREME, and not extreme, headfilies.

I'll listen for a bit more, let it run in overnight and tomorrow, and if all is well, I will post tech contact info. Might be useful to have a pro tech when needed.

P.L.H.



[IMG][/IMG]







post #176 of 407
Quote:
Originally Posted by kevin gilmore View Post
<snip>

Now i know for a fact
that mikhail has a NC controlled vertical mill and is capable of
making nice holes in things.
He probably had to sell it along the way.

Quote:
http://gilmore.chem.northwestern.edu/skylab-12.jpg
The 4 hex head stainless steel screws are the new mounting
screws, drilled and taped on my personal mill in my basement.
I really like all the file and scratch marks...

finished unit
http://gilmore.chem.northwestern.edu/skylab-13.jpg
It kills the looks, but it's a lot better to have dead looks than a dead amp.

Quote:
<snip>
how about that quality grinding job on the pot after cutting it off too short.

All of this is the most simple of stuff and he could not even get that right.
It simply boggles the mind.
post #177 of 407
I wired up the beast last night, adding the 25amp rectifier which gracefully fit into the existing position. When I plugged in the power cord I got a flash ...the 4th of July instead of Christmas!

The culprit was a solder blob that bridged the hot and neutral AC inlet tabs. One fuse later I had 9v and 170v from each supply without the tubes in place. Hopefully the unloaded filament supply will calm down to 6.3?

I did not put in tubes or try for music yet as I want to look inside one more time for other soldering blunders before risking my Tungsols.

Nice going on your amp Nurxhunter!

The adventure continues...
post #178 of 407

obervations

Thanks Paul.

Oddly, I could not go to sleep with the amp on, the sound was not quite doing it for me. Instead of a 396A, I popped in a CBS 5692 sitting in another amp handy. Bingo, the smooth tube signature I looked for, much better bass, better stage presence for Frank--a richer sounding Frank. Wider orchestra.

It appears the sound character of the amp has changed with the upgrade, whereas the clearer sound of the 396A before the fix seemed perfect, now, it seems a mite too detailed, and lacking just a touch of bass. With a 6sn7 in place, I liked it quite a bit better. Before the fix, the 6SN7 sounded way to soft for my taste with 6SN7 as driver. Will have fun rolling a bit again.

Ran all night, transformer cover barely warm. The case does get quite a bit warmer--not hot, though. The tubes get warmer than before the fix, not ultra hot. Before, I could touch their top (6AS7) comfortably, now I cannot. Still, this is a quiet amp--before and now, with plenty of strong,. clean overdrive capability. Impressive.

Imagination? Preliminary findings.

If 'real', i winder if the different preferences for the driver from so many SP owners had something to do with different builds. Imagination?
post #179 of 407
You could touch the top of a running 6as7 before? The old transformer must have been sagging a ton and barely providing enough filament current for the tube to function. There is no way a running tube of that size should ever be able to be touched "comfortably"
post #180 of 407
Quote:
Originally Posted by tkam View Post
You could touch the top of a running 6as7 before? The old transformer must have been sagging a ton and barely providing enough filament current for the tube to function. There is no way a running tube of that size should ever be able to be touched "comfortably"
Indeed! I have a half-dozen amps that use the 6AS7 - if you touch the 6AS7 when the amp is running, you're going to get burned, every time. This is as it should be.
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