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Messages - amptech

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826
Might not be a problem to use tubes of different kinds, but as you experienced; they have to be in good shape! As I said earlier, if you suspect a tube have gone bad - replace it. Do not use a valueable amp with bad tubes, you don't wanna ruin it on purpose!
Have your tech measure the tubes and maybe move them around until they pull about the same current.

You could (since you are no stranger to electronics and can use a soldering iron) just install some good 1W1R1% resistors between cathode and ground (depending on the design, but I guess the cathodes here are grounded) and you can easily measure and bias yourself. 1mV = 1mA across the resistor.

827
That's what I was thinking.  I just hope the place by my work has 2-5W resistors in something other than ceramic.  I might have to mail order.

I use 5W wirewound (rs#762-9469, cheap but reliable) and always replace all if they look iffy or too low W. Carbon comp screen grid resistors I throw away. Screen grids in tubes is a weak spot in todays tubes.

As a side note, if you suspect one gassy tube or have a bad feeling for it - just replace it. Measure the others and buy one that test similar, people sell good used ones really cheap.

828
The Outpost Cafe / Re: RIP Toots Tielemans
« on: August 22, 2016, 10:35:53 PM »
RIP Toots. The first jazz group I played in was simply called Toots, and bluesette was the first jazz tune I learned.
Great musician.

829
Guitars Etc. / Re: Fender Blues Junior Amp Resurrection
« on: August 20, 2016, 01:44:35 AM »
Looking good!

831
Guitars Etc. / Re: Guild S-200 Thunderbird reissue?
« on: August 17, 2016, 11:01:02 PM »


I didn't care for the way they sounded, but I wouldn't agree that they were crap just because Curtis Novak thinks they are.

Curtis makes fine pickups, but he does say things about magnet wire I do not always agree to. 43 AWG wire is not equal to thin 'anemic' sound; many great pickups are made with thin wire. And ceramic magets does good things too, in some designs. I had to look twice at a pickup he calls the 'Charlie Christian P bass pickup'. It's just a tall coil P bass pickup with 38 AWG wire. I know the thick wire was used on the very first version of the bar pickup, but the narrow sensing area of the bar polepiece (as well as the cobalt steel magnets) contributes much more to the sound than just the wire, he's gotta know that... The later CC units with normal wire still sound like CC pickups.

Anyway, I do agree with him that most of the mass produced asian single coil pickups made on a plastic bobbin with glued on ceramic magnets (and whatever eire they use) lack the ability to reproduce a good guitar tone. But they are also the reason I sell quite a few homemade strat pickups, so I can't complain!

832
Gibson Basses / Re: Nice '62 EB3 on the bay
« on: August 13, 2016, 12:20:36 AM »
Shouldn't the crown inlay be up higher on the head?  I thought it moved to the middle position sometime in 1963.

Dang, didn't see that! My '63 have a high crown.. Didn't see anything iffy at first, but something must have been done to it!

I'm getting sloppy!

EDIT: I asked the seller, he says he is no collector and would not know about such things. He says there might have been a headstock repair, but cannot tell for sure.

833
Gibson Basses / Nice '62 EB3 on the bay
« on: August 11, 2016, 10:56:14 PM »
This one looks fine, rare to see a good one this old listed as 'EB-0'

http://www.ebay.com/itm/1962-Gibson-EBO-Bass-Guitar-/322221256962?hash=item4b05e23102:g:MP0AAOSw0UdXqN2k

If it does not skyrocket in the last minute it might be a good investment!

834
Bill's Shop: Projects, Mods & Repairs / Re: Baby Bird
« on: August 09, 2016, 10:35:55 PM »
Didn't Alembic call their stanley clarke bass 'piccolo'? With bass A D G C strings?

835
Guitars Etc. / Re: Fender Blues Junior Amp Resurrection
« on: August 07, 2016, 10:59:50 PM »
Fender amps with smoked screen grid resistors must be the most common sight in my amp shop.
It's a good thing you installed a bias pot, all in all it's worth it to do some safety mods to these amps.
I install 5W screen grid resistors on all these fender amps. In theory you do not need 5W, but 1W or 2W units do
blow up all the time on these amps. The IC caps is also not he best, they fail fairly common too.

But they are good amps when they work!

836
Gibson Basses / Re: 1 meg pots and TB Plus pickups
« on: August 05, 2016, 11:11:46 AM »
No amount of passive circuitry will add elements back to your tone that weren't there in the first place.

No, but it can take it away, and that is what georgestrings is trying to compensate for if I understand him right.

837
Gibson Basses / Re: 1 meg pots and TB Plus pickups
« on: August 04, 2016, 11:38:46 PM »
Don;t know much about what makes the pups unique but it could also be something there too (like their DCR that makes 1 Meg pots work better; not sure)


I think they have about the same DCR as a P90. The bobbin is really very much the same as a P90, but is forbon instead of plastic. I guess that the wire being wound directly around a short rod magnet makes them sound more fenderish than P90's. 

838
Gibson Basses / Re: 1 meg pots and TB Plus pickups
« on: August 03, 2016, 10:57:19 PM »
Now you've got me curious. What's special about Jazzmasters that makes 1M pots appropriate?

I've never actually played a jazzmaster, but really like the sounds other people get from them, have a fantasy of owning one someday if/when I can justify a 6-string purchase.

I replicated a couple of 58-64 era pickups last summer, for a guy who built a jazzmaster.  Last time I spoke to him, he still had not got around to the electronics - so I might have to put everything together :)

I could be wrong here (haven't got the schematics here) but the jazzmaster have a circuit with volume and tone that works on the neck pickup only, in addition to the main circuit. So the two 1M volume pots in paralell will make the reistive load 500K in total, at least for the neck pickup. I think they used linear taper pots too.

839
Holy crap Clapton is coked up to the gills in that vid.
A little spoonful of coke?

At least there is lots of nice clips of Jack's beautiful bass!

840
Gibson Basses / Re: 1 meg pots and TB Plus pickups
« on: August 03, 2016, 06:03:33 AM »
I really don't want to add an active circuit, I just want to "take the blanket off" these pickups, so to speak - while retaining the ability to blend them, or roll them off altogether in some situations(on stage or at rehearsal)

If you feel you want to take off a blanket, the pot trick (1M or no load) will not do that - not that much effect. Sounds like different pickups or stainless steel strings is more likely to have that much effect.

At any rate, it doesn't look like anyone here has ever actually tried a 1 meg volume pot with a TB Plus pickup, so I might end up being the guinea pig... I'll be sure to post the results if I end up trying this, though...

I have installed many 1M pots and a couple of no load pots for guitar players. There is a lot of talk now about how much you can change or 'sculpture' your sound by tinkering with tone pots and cap values. I personally don't think it is worth it, I just tried to explain what happens. Other than a direct out option on one of my own EB3's, I usually end up with stock wiring. Other than fender jazzmasters and some other, 1M pots aren't much used and for good reasons.

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