Tube-pre/DI project
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Posted on Nov 14, 2005 10:56 am
Hue
Pinnipedal Czar (: 3=
Member Since: Apr 11, 2004
I have this very old, but very clean Sears-Silvertone tube amplifier that I've been considering as of late . I never use the thing because it doesn't have a grounded power-plug, and I've only used my amps for live stuff, so what I've been thinking is that this may make a sweet 'lil di/preamp for recording, though I may be wrong .
I thought maybe some of you guys would know if there is a proceedure to 'convert' this thing... i.e. bypass the amp, and ground the electrical plug... if it's worth doing, or even if this is possible at all ? OR, even if I am mad even considering it, as some of the older tube amps have been known to be gems, as is .
In it's current state, it has two 12AX7 tubes for the pre amp with 2-mic, and 2-instrument inputs(all 1/4"), a 70w amp with two 6L6 tubes, running to a 12" speaker... there's a tremolo effect built in it, but is has stopped working .
Any suggestions would be helpful .
Oh, it's model 1482 .
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Noize2uCzar of MidiAdministrator
Since: Apr 04, 2002
Nov 14, 2005 10:06 pm Hue, before you go wacking about on that thing you really should double check it by model and serial number.
Some of those old Silvertone amps are now worth some money. If you have the model and serial number post em here and I can check with a local guy here who does nothing but tube gear and vintage stuff. Builds his own line as well os class A and other buotique type amps.
Better yet if ya got a picture you can post.
But ya, grounding is a big thing to prevent accidents.
HuePinnipedal Czar (: 3= Member
Since: Apr 11, 2004
Nov 15, 2005 09:51 am Here's one on e-bay...
cgi.ebay.com/VINTAGE-SEAR...1QQcmdZViewItem
The checking of it I did turned-up nothing to show that it was anything sought after, yet I see this as a good thing, since I only payed 20$ for it, and it's in great shape . If I decide to take the amp/speaker out and make a DI of it, it may be the ticket to tapping a latent asset of this thing... or I may just butcher a crappy tube amp... either way I'm going to learn something . I'll ground it and play through it one more time before I try the DI thing, it's been a while since I the last time, maybe my ears/tastes have changed, so...
TadpuiI am not a crook's headMember
Since: Mar 14, 2003
Nov 15, 2005 11:01 am It may even be worth hearing some other tubes in the thing. If its too clean, maybe try some other power tubes in there that break up more easily. A low-wattage tube amp is a very sought-after piece of gear nowadays. Perfect for home recordists because of the great tube distortion at lower volumes. Heck, maybe even all it needs is a good overdrive pedal in your signal chain.
At very least, you could get more than $20 for it on eBay.
Heck, you may be able to get more than $20 for it from me ;-)
pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Nov 15, 2005 11:22 am The iron in it is worth 20$ alone.
I'd be skeptical on the 70w though. Most 2 6l6 tube amps put out around 35 - 40 watts. And 40 is pushing it. If it's running in Class B, then it can be higher power, but it'd sound like poop, having the sine waves not overlapping when crossing from + to -.
Just looked at the ebay one, that shows 6v6 output tubes. Those are even less power than 6l6 tubes. Somewhere around half. So if there's 6l6 tubes in there instead (they will fit), then it's only a guess if the circuitry is adjusted to run 6l6 tubes. Even if no changes have been made, the amp may take the 6l6s without problem, but it wouldn't be optimal for the tubes, or the output transformer.
The caps may be worn out as well. It may sound crappy if the caps, and possibly some resistors, and/or tubes are worn out.
just a thought
HuePinnipedal Czar (: 3= Member
Since: Apr 11, 2004
Nov 15, 2005 02:09 pm I may have been wrong about the power tubes, I thought I saw 6L6, perhaps they are 6v6... not sure at the moment, here at work . As I recall though, it is a very clean sounding amp, which is why I thought it might make an ok mic-pre, or DI after getting around the amp part of it .
An overdrive pedal might be just the ticket for a nice guitar sound through it, though...any recomendations for one to try, Tadpui ?
pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Nov 15, 2005 02:22 pm If you're not going to dis-assemble it, you should be able to add a line level output after the preamp without hacking it up. Maybe just an xlr or TS jack on the side. You'd want to switch out the output section, so it's not making noise out the speaker, but it shouldn't be super difficult.
Lot's of tube amps sound good with a tube screamer in front of it. Some like the Boss ds1 or sd1 on a tube amp, among others. I play my gt-6 through my super, is very nice.
TallChapAnswer:On a good day, lipstick.Member
Since: Jun 24, 2004
Nov 15, 2005 02:23 pm Try the Jekyll & Kyde pedal. Thought by some to be quite lovely...
I've been really pleased with Tech-21 products like the Tri-AC (Although this one works best as a pre-amp before a power amp).
Yeah, it's worth more than $20 in parts, that amp.
HuePinnipedal Czar (: 3= Member
Since: Apr 11, 2004
Nov 15, 2005 03:19 pm Great idea on the line-out with a switch !
The gt-6 is something I've been looking at, as well as the gt-8 . Apparently, those are the only two fx-boards that will allow reverb-tails, and delays to decay naturally between stomps... very cool boards . Tech-21's stuff looked nice as well... never listened to any though .
Thanks guys, I may get to do a little work on it this weekend .
TadpuiI am not a crook's headMember
Since: Mar 14, 2003
Nov 15, 2005 05:16 pm As far as stomp-box distortion pedals, I think that the TubeScreamer (not the grey plastic one) and Boss DS1 are the most popular, and probably for a reason.
I really like those Boss GT-x processors. OldDog uses one and he gets some pretty convincing sounds out of it. Beats the pants off of any other modeler I've heard.
Noize2uCzar of MidiAdministrator
Since: Apr 04, 2002
Nov 15, 2005 07:30 pm Hue, I chatted with my buddy and he said that one is probably not a big seller, although he has seen em go for above the $100.00 mark. so someone must want em. But hey if you can get a nice tube pre outa the thing, then I would surely give it a try.
Also, he did mention trying out some newer tubes to beef it up a bit.
jetgloMember
Since: Jul 23, 2004
Nov 30, 2005 01:52 pm audioasylum.com is a great place for esoteric information.. look for the thread called "vintage" or look for "tubes" there is a wealth of info about old amps etc.
My personal take on your situation is that you should keep your amp as is since you say it has a sweet tone, which is definitely a combination of pre amp, output, and quality of wiring and structure. Keep it as is!
You can get a fantastic pre amp kit from Paia.com for about 110.00, I got one and with no prior electrical experience have a really nice two channel tube pre amp with which I have come up with my own "cocktail" of tubes to get my "perfect tone" IMHO .. I am in the same boat as you though with an older amp.. I have a two channel 1952 Stromberg Carlson power amp in which I recently had new and better capacitors installed, solders tightened/cleaned etc (about $100) these amps are now worth about $500.. it sounds GREAT but I really don't like the non-grounded cord so I'll take it back to the man who worked on it.. an old man.. a restorer of vintage radios etc.. which is a good idea to find BTW.
jetgloMember
Since: Jul 23, 2004
Nov 30, 2005 02:02 pm Ok I put words in your mouth... by clean I thought you meant nice tone.. sorry, I read too fast and answer too quickly.. but everything else stands!
Nov 30, 2005 04:43 pm I love the sound of some soaked 6V6's (in my deluxe reverb). They are harmonically richer than the 6L6's IMO.
As far as the grounding issue, I don't think it is going to change your sound so much as it is a safety issue. In my amps that are grounded with a ground lift toggle, the sound at idle is always more quiet with the ground lifted.
It doesn't get pleasing dirty totally cranked?
Here's my $.02.
I would try a different speaker.
I would try pluging the speaker level out (using a parallel out or the thru to maintain the load on the amp) into a direct box with the pad engaged.
I would sell it on ebay and get one of those 100.00 epiphone tube combos. Which will definitely get a pleasing sort of dirty.
I would not modify it in any way (short of swapping tubes) or it will be worth substantially less, negating option 3.
I love these guys www.tubedepot.com/
And I would go for the JJ's (as others have said).
Good Luck.
Dec 01, 2005 12:16 pm Before attempting a line out w/switch, remember that you must have a resistive load across the output transformer. Otherwise you chance ruining the amp altogether. Heres a site that'll explain how to do it:
pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Dec 01, 2005 12:27 pm Good point, but not the right kind of line out. This would be right after the preamp, not at the end of the signal path. He was looking to just have a preamp output, without dis-assembling the rest of the amp.
HuePinnipedal Czar (: 3= Member
Since: Apr 11, 2004
Dec 01, 2005 01:12 pm Well, I didn't get to mess with it last weekend, but I will this one for sure, as I'm gon'na have the whole weekend free to mess around in the studio . Hoorah ! I'm going to run it through a few guitar/stomp-box tests before I start the trying other speakers/tubes . Maybe I'll be able to post some results .
TallChapAnswer:On a good day, lipstick.Member
Since: Jun 24, 2004
Dec 01, 2005 04:22 pm $0.02
The Epiphone Valve Junior is fabulous!
Got one.
Love it.
Really love it.
Maybe too much.
Maybe I've said too much already.
I gotta go.
Dec 02, 2005 09:56 am Quote:
Good point, but not the right kind of line out. This would be right after the preamp, not at the end of the signal path.
True enough, but if you put in a switch to cancel out the speaker, then there is no resistive load on the output transformer. It's mandatory in a tube amp to have that resistive load for the output tranny to drive. It is extremely easy to add in a resistor for this purpose if you are already putting in a line out jack.
pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Dec 02, 2005 10:53 am I would think that the pre-amp switch would cut signal going to the rest of the amp. Therefore, the following tubes, and iron and speaker will still be connected, just not doing anything.
That may not be a very good solution, given the likelyhood of noise coming from the rest of the amp, and out the speaker.
If disconnecting the speaker is sought, then your point is very good, put a load across the transformer, inplace of the speaker.
I suppose a DPDT switch would work, one side switching signal to A: line out, or B: rest of amp. Then the other side of the switch A: switches out the speaker for a resister, or B: normal speaker operation.
That doesn't seem to hard to do, if you're already in there.
