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cGil

Bored silly

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I'm going bonkers waiting for SEwatt to come back online so I can get back to the fun of finding new ways to void all my Epiphone warranties. I think it's really beginning to get to me. Everything looks real short. Like the thread list. I was sure there was a thread around here somewhere that mentioned battery powered amps. Must've fallen off the edge of page 2 or something.

 

Anyway, I mentioned this possibility... http://www.pentodepress.com/receiving/street-musician-amp.html

 

As soon as I found out how CHEEP those tube are, the bug bit me.

 

MicroWatt-RawTop.jpg

MicroWatt-Heaters.jpg

 

Gil...

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Thought I might mention that's a Rat Shack 4" x 6" project box with 7 pin ceramic tube sockets on it. The switch is a center off type, for use as a combination Standby/Power-On switch. Volume, Tone, and guitar and speaker jacks it's all it gets. Whether or not I'll be able to get all the batteries inside that Rat Shack box along with everything else is gonna be another matter. Gotta build the amp first, then I'll see if there's enough room left inside the bottom of the box for a D-cell, and a bunch of 9-Volts. Either way, it's gonna be a really small tube amp. 8-[

 

I'm building this thing cuz when the power goes out, whatcha gonna do, right? But as usual, I'm taking my sweet time about it. Hey, it's a Gulf Coast thing, go figure. Anyway, as I was posting the above message, a thunderstorm blew through and guess what? Yep. Power went out. =D> Talk about a motivational experience! #-o

 

Gil...

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I'm going bonkers waiting for SEwatt to come back online so I can get back to the fun of finding new ways to void all my Epiphone warranties. I think it's really beginning to get to me. Everything looks real short. Like the thread list. I was sure there was a thread around here somewhere that mentioned battery powered amps. Must've fallen off the edge of page 2 or something.

 

Anyway' date=' I mentioned this possibility... http://www.pentodepress.com/receiving/street-musician-amp.html

 

As soon as I found out how CHEEP those tube are, the bug bit me.

 

[img']http://i166.photobucket.com/albums/u103/cgil155/MicroWatt-RawTop.jpg[/img]

MicroWatt-Heaters.jpg

 

Gil...

 

So do I understand this correctly....your plate power comes from 5 9volts in series? If so your gonna need a second box for the power supply....Right?

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Just think you're bored with Gustav on one side and Hanna on the other... I think you need to build a raft.

 

:-k Oh! Silly me,, how else are you going to keep yourself entertained on that raft with out a battery powered guitar amp.

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very nice work=d>

 

I'm in the middle of my first EL84/6V6 parallel scratch build and now sewatt is down! I have nowhere to ask my "noob" questions like, where do I put the cathode cap and resistor for the octal? terminal strip?

 

Gustav is fast approaching Gil...if it turns your way you'll definatly need that amp up and running!

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My kid forgot my bulb two days in a row.

the bastige.

now I'm thinking about copying your batt-amp!

TWANG

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My kid forgot my bulb two days in a row.

the bastige.

now I'm thinking about copying your batt-amp!

TWANG

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Thanks guys. Yeah, the Rat Shack box is only a couple inches deep, but I'm pretty sure the 9v's will fit. It's the D-Cell for the heaters that I'm mostly worried about. But I have a wooden "treasure chest" stash box I picked up cheep, and the Rat Shack box can sit in that with plenty of room around the sides. So if I use that, I can keep the batteries outside the main circuit box. Probably be best to do it that way so I won't have to unscrew anything to swap batteries. And it'll keep the batteries from beating up the spaghetti.

 

Kshef. Don't sweat it! You can hang the octal's cathode resistor and cap between the socket pin and pretty much any ground, including the bolt holding the socket to the chassis! But traditionally it's considered best if it's grounded to the same place as the power supply filter caps for the plate and screen. Most recently I used a single terminal for it, which was wired straight to the star ground chassis bolt where all the green ground wires come together. Worked just fine.

 

Gil...

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Thanks guys. Yeah' date=' the Rat Shack box is only a couple inches deep, but I'm pretty sure the 9v's will fit. It's the D-Cell for the heaters that I'm mostly worried about. But I have a wooden "treasure chest" stash box I picked up cheep, and the Rat Shack box can sit in that with plenty of room around the sides. So if I use that, I can keep the batteries outside the main circuit box. Probably be best to do it that way so I won't have to unscrew anything to swap batteries. And it'll keep the batteries from beating up the spaghetti.

 

Kshef. Don't sweat it! You can hang the octal's cathode resistor and cap between the socket pin and pretty much any ground, including the bolt holding the socket to the chassis! But traditionally it's considered best if it's grounded to the same place as the power supply filter caps for the plate and screen. Most recently I used a single terminal for it, which was wired straight to the star ground chassis bolt where all the green ground wires come together. Worked just fine.

 

Gil...[/quote']

 

Actually gill I had a thought what about 2 ratshack boxes back to back? You could put rubber feet on the bottom and access the batteries from there...it would also give the amp some stability and weight. BTW be safe with Gustav...I know its going well west of you...but the back side of those things are always nasty.....you still may see some sh#t!

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I'm more worried about StarGeezer and my step-bubba and various friends and cohorts over in that area. That Gustave monster is headed straight for 'em! I still can't believe this thing is following the projected track. Kinda boosts my faith in the National Hurricane Tracking Center. Well... For the moment anyway. [-X

 

Meanwhile, here's some pics of the treasure chest, which is basically what this amp is headed toward looking like.

MicroWatt-MoreSpaghetti.jpg

MicroWatt-TreasureChest.jpg

 

Gil...

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I'm more worried about StarGeezer and my step-bubba and various friends and cohorts over in that area. That Gustave monster is headed straight for 'em! I still can't believe this thing is following the projected track. Kinda boosts my faith in the National Hurricane Tracking Center. Well... For the moment anyway. [-X

 

Meanwhile' date= here's some pics of the treasure chest, which is basically what this amp is headed toward looking like.

MicroWatt-MoreSpaghetti.jpg

MicroWatt-TreasureChest.jpg

 

Gil...

 

That's cool....plenty of room in there! Yeah I PM'd Geezer and he's gettin out of harms way...goin' up to play some blues with a buddy and takin' 4 amps with him!

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Geezer's only taking 4 amps? Well, at least he won't run short of tones, or assets to sell if the cash runs short! Smart man. I wonder how many amps will make it back home? [-X

 

I dunno, though. This project amp just doesn't look quite like I had envisioned it just sitting loose in the box like that. The next larger size Rat Shack project box won't fit inside the treasure chest, but it turns out the aluminum top for the 5" x 7" box will fit almost perfectly with only 3/4" slack at one end. I had planned to use that larger top plate with some walnut veneer on top, but couldn't remember where I stashed my veneer in time. Now it's too late for that, cuz those sockets are getting wired in! If only I hadn't top-mounted them. #-o Oh well, I'll just have to think of something else to gussy it up when the amp's finished. No big deal.

 

Gil...

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Well, hang on before you buy a bunch of tubes and sockets. For all we know, this thing may blow chunks. Besides, the article did mention that it was so microphonic it'd make a good seismic detector, but I'm gonna find out. Maybe if I pack it in there with some felt? 8-[

 

Anyway, I got the eyelet strip fabricated, and I'm just up here giving my old back a much needed break from that bench stool before I dive back in to solder up the signal caps and resistors. I actually think I may have more parts on the floor than on the bench at the moment. ](*,)'

 

Gil....

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I think I would be on the lookout for an ultimately cool box for the knobs to hang out of...I'm thinking an all wood cigar box or a kids lunch box. The lunch box would rock because of all the cool flavors and you could open the lid to access everything and change batteries. Also a small speaker might be cool. Not a speaker you would really want to use but one there for more of a novelty...like this:

http://cgi.ebay.com/ZVex-Nano-Amp-1-2-watt-guitar-amp_W0QQitemZ300254523867QQihZ020QQcategoryZ10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

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Here's what he said about battery life"

 

Let's take inventory. I paid 2.25 euro for the D cell and 5.49 euro for each 9-volt battery. (OK, I was ripped off on the 9-volts, but science is science.) That comes to 29.70 euro. After 16 hours of full-power playing, without a pause to sign a recording contract, my signal generator has burned 1.86 euro per hour in batteries. That translates to almost 3 dollars per hour in the CTA tunnel at O'Hare, which represents a lot of cash on a slow travel day. I better keep my day job.

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Here's what he said about battery life"

 

Let's take inventory. I paid 2.25 euro for the D cell and 5.49 euro for each 9-volt battery. (OK' date=' I was ripped off on the 9-volts, but science is science.) That comes to 29.70 euro. After 16 hours of full-power playing, without a pause to sign a recording contract, my signal generator has burned 1.86 euro per hour in batteries. That translates to almost 3 dollars per hour in the CTA tunnel at O'Hare, which represents a lot of cash on a slow travel day. I better keep my day job. [/color']

 

Yeah, looks bad, huh! Maybe the guy should've had a Rat Shack battery club card? Four 9v- are $5 bucks. Gonna use 8. Throw in a D-cell and we're up to $12 bucks, which comes to 0.75 cents an hour. Add in the fact that realistically, I'm only going to play it for a few hours at a whack, so it should coast through 3 or 4 days of power blackout before I have to throw in a new set. I suppose I should just add indiviual jacks for power instead of directly hardwiring the battery clips to the switch. And maybe consider rechargable batteries. But those options depend on how it sounds as to whether I'll bother worrying about it.

 

Meanwhile, back at the fringes of Gustave... Boy is it ever raining now! A couple minutes ago it was coming down in horizontal sheets, but suddenly the wind stopped, and now it's coming straight down. ooops. Here come the winds again. It's gonna be a fun day. Even my cats are having fun. They woke me up by chasing their breakfast pidgeon around in my bedroom. I keep telling 'em not to play with their food so much, but they won't listen. So I snagged it and chucked it out the window. Tough love, perhaps, but they never clean up the mess. Got feathers everywhere! >8-[

 

Gil...

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I'm into RC and have a slew of lithium polymer packs laying around. I'm betting this thing could run off of a two or three cell lipo and play for a loooong time and they are rechargeable.

Cgil maybe we could work out a trade for batteries and you make an extra one. That would rock.

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No progress to report on the amp so far. Between the wild wind and the storms, the power company tree guys needing help navigating their truck through my jungle, the laundry (oops, not finished), the cleaning (also not finished), the cooking and feeding of mom and the cats, and chatting with refugees who stopped to visit... it has been busy Labor Day "holiday", that's for sure! I've got a bunch of VA clinic appointments keeping me away from the bench tomorrow and Wednesday. I really need to take a break and get this thing finished and fired up tonight.

 

The lithium polymer battery idea sounds interesting. What voltage are they? How many recharges can they take? Do they get senile with charge-memory problems? etc., etc. I was considering scrounging up five or six kiddie cart 12v gel cells for extended camping trips or whatever, but was thinking three 24v batteries would probably be even better. 72v to the plates would probably make that sucker sing! We'll see.

 

The heater at 1.5v is another issue. I could string all the tubes in series if there was a 7.5v battery. Not much chance of that I guess. The power pentodes can be configured for a 2.7v heater supply, but that would only bring it up to ~10v. But! If I add another preamp stage, it'll be a ~11.5v heater requirement! That's close enough to 12v. The real issue with it is the Christmas tree light effect... if one tubes goes south, they all stop working; and finding which one went bad means I'd probably have to go through the whole lot. Murphy's law will ensure that it'll be the last one checked, no matter what the odds. I think I like parallel heaters, so I guess I'll just have to bring a few rechargeable D cells. At least the bias battery will probably last a while.

 

Gil...

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A two cell lipo is 7.4. I would be curious to see what kind of life we could get out one, I think a lot longer than any battery off the shelf. 3 cell is 11.1. I can get all the 2 cells we want and could throw in a charger. They don't have memory and for this type of application they might actually last a while. I have lipos that are pretty damn old. Let me know and I'll send some your way!

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Let's see. Ten batteries for the plates would be good, cuz at a 74v plate voltage, I'm guessing one more 7.4v for the bias might be about perfect. Add one more for serial heaters, and there ya go! Total amp power supply from a bank of batteries that use only one type of battery. I'd suffer through tube swaps for that I suppose.

 

So how heavy would a dozen of those puppies actually be? For that matter, just how big are those things? Is there a multi-battery charger for those things? I suppose I should check out some local RC shops around town and see what the scoop is. Might as well. Can't say I'm not curious about what sort of trouble I could get into with remotes and servos and such. :-

 

Gil...

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