First the bad news - all used and will need to be tested (not sure where or how yet...)
4x of 7867 tubes
1x of OD 3
2x of 12AU7
2x of 5U4GB
I have almost no idea. I know that the 12AU7s are occasionally used in guitar amplifiers and I think that the 7867 are power amplification tubes. I am guessing that the OD 3 is a rectifier? 5U4GB - no clue. I'd appreciate information if anyone is willing.
Now - my story - I am 34 years old and I just started to play the electric guitar. I don't have an amp yet. I was looking at bedroom tube amps like Bugera V5, Epiphone Valve Jr. and whatnot and - through a reference to modding amps - I came across a few schematics that looked ridiculously simple. I thought to myself "why should I pay 200 dollars or more for something that I could solder together myself?".
That was before I found out that vacuum tubes aren't abundant cheap things that you can acquire for pennies.
Undaunted - I started to look through piles of old electronics at work. That's when I discovered a chassis with all of these tubes mounted. There's also 3 hefty-looking transformers of unknown origin that I haven't had a chance to remove yet.
I'm interested in building an amp for myself. I would like to keep the cost as close to "free" as possible but of course I would be happy to buy replacement tubes if need be, or a power transformer if the unknown transformers won't serve my needs. Is there a good way to identify the ratings of an unknown transformer?
4x of 7867 tubes
1x of OD 3
2x of 12AU7
2x of 5U4GB
I have almost no idea. I know that the 12AU7s are occasionally used in guitar amplifiers and I think that the 7867 are power amplification tubes. I am guessing that the OD 3 is a rectifier? 5U4GB - no clue. I'd appreciate information if anyone is willing.
Now - my story - I am 34 years old and I just started to play the electric guitar. I don't have an amp yet. I was looking at bedroom tube amps like Bugera V5, Epiphone Valve Jr. and whatnot and - through a reference to modding amps - I came across a few schematics that looked ridiculously simple. I thought to myself "why should I pay 200 dollars or more for something that I could solder together myself?".
That was before I found out that vacuum tubes aren't abundant cheap things that you can acquire for pennies.
Undaunted - I started to look through piles of old electronics at work. That's when I discovered a chassis with all of these tubes mounted. There's also 3 hefty-looking transformers of unknown origin that I haven't had a chance to remove yet.
I'm interested in building an amp for myself. I would like to keep the cost as close to "free" as possible but of course I would be happy to buy replacement tubes if need be, or a power transformer if the unknown transformers won't serve my needs. Is there a good way to identify the ratings of an unknown transformer?
7867 is a power tube... http://frank.pocnet.net/sheets/127/7/7867.pdf
keep looking around and you may find what you need....
meanwhile this thread is going to the Instrument section since you are building a guitar amp...
keep looking around and you may find what you need....
meanwhile this thread is going to the Instrument section since you are building a guitar amp...
That site is a great resource Frank's electron Tube Data sheets
A few more...
http://frank.pocnet.net/sheets/049/0/0D3.pdf
http://frank.pocnet.net/sheets/093/1/12AU7A.pdf
http://frank.pocnet.net/sheets/049/5/5U4GB.pdf
A few more...
http://frank.pocnet.net/sheets/049/0/0D3.pdf
http://frank.pocnet.net/sheets/093/1/12AU7A.pdf
http://frank.pocnet.net/sheets/049/5/5U4GB.pdf
Maybe building a stage around the 12AU7 would be a good place to start as it's a bit more flexible to set up. Later it can become the driver stage for something like the 7867, or part of a pre/effect.
If the transformer that came with these is still connected then you could trace the circuit. Resistors of a certain value are often used to bring the voltage down for each stage. If you use the transformer with less stages than it originally powered, or if you choose to use modern rectifiers (instead of the 5U4), these resistors may not be a large enough value. If you want to use the 5U4 and regulator it might be better to use them exactly as they were originally (once you clean it up).
You may want some capacitors that can handle the conditions, some don't age well and will want replacing.
If the transformer that came with these is still connected then you could trace the circuit. Resistors of a certain value are often used to bring the voltage down for each stage. If you use the transformer with less stages than it originally powered, or if you choose to use modern rectifiers (instead of the 5U4), these resistors may not be a large enough value. If you want to use the 5U4 and regulator it might be better to use them exactly as they were originally (once you clean it up).
You may want some capacitors that can handle the conditions, some don't age well and will want replacing.
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Pls. note that cost saving is rarely achieved when building a tube amp, unless you've got all the expensive parts (tubes, transformers(!), speaker) already laying around. It will be rewarding and can be fun though!
OTOH: small tube amps (tops or combo's) can be found used for 100 EUR/150USD and can serve either as an amp, or as a modding-platform.
Hi there!
I'm a long way off being even knowledgeable about toobz (I've only built a couple of em, and I was stronger on the building than the understanding), but it seems to me that you've most of the building blocks to make -something-.
I would imagine that with the chassis, transformers and tubes, you are indeed most of the way there - you just need to pick a circuit and wire her up! (insert safety comment here)
May I suggest you photograph whatever you have available (ie chassis, transformers, and toobz) and I'm sure a few folk can make suggestions as to what might be achievable.
I'm a long way off being even knowledgeable about toobz (I've only built a couple of em, and I was stronger on the building than the understanding), but it seems to me that you've most of the building blocks to make -something-.
I would imagine that with the chassis, transformers and tubes, you are indeed most of the way there - you just need to pick a circuit and wire her up! (insert safety comment here)
May I suggest you photograph whatever you have available (ie chassis, transformers, and toobz) and I'm sure a few folk can make suggestions as to what might be achievable.
100 watts may be more than i can ever use.
I was thinking something more modest like a fender champ. i like the features on the bugera v5 and the schematic isn't too bad either - so maybe a combination between that and the fender champ? I want it to sound like the champ but i'd love to be able to have more features like tone controls. Then add a reverb circuit and an attenuator of some sort. The bugera attenuator switch has been maligned by many for 'killing' the tone - so i'm guessing that whatever they did had to have been the "cheap way" -there's got to be a better way to reduce output. The bugera has ,1 watt, 1 watt and 5 watt settings. I think i'd be happy with that. I anticipate using the lowest settings more often than the highest settings, but i must admit that I wouldn't be opposed to a higher ceiling - maybe 15 to 20 watts or so...
But i am not really ready for that yet. I need to figure out what i've got to work with. A used bugera v5 might turn out to be cheaper in the end but I am interested in doing this for myself even if i end up having to purchase replacement tubes and iron and whatnot. I have one big advantage in that i'm working as an electrician in a very old foundry and there is discarded equipment on shelves all over the place. There is also a guy who works a lathe who can machine just about any piece i can think of and a pattern shop that has tons of scrap wood if i decide to use that. I think that photos of what i've collected so far is a good idea and i'll post some as soon as i can get a free moment. That might not occur for another 12 hours yet, but i'll get them eventually.
I was thinking something more modest like a fender champ. i like the features on the bugera v5 and the schematic isn't too bad either - so maybe a combination between that and the fender champ? I want it to sound like the champ but i'd love to be able to have more features like tone controls. Then add a reverb circuit and an attenuator of some sort. The bugera attenuator switch has been maligned by many for 'killing' the tone - so i'm guessing that whatever they did had to have been the "cheap way" -there's got to be a better way to reduce output. The bugera has ,1 watt, 1 watt and 5 watt settings. I think i'd be happy with that. I anticipate using the lowest settings more often than the highest settings, but i must admit that I wouldn't be opposed to a higher ceiling - maybe 15 to 20 watts or so...
But i am not really ready for that yet. I need to figure out what i've got to work with. A used bugera v5 might turn out to be cheaper in the end but I am interested in doing this for myself even if i end up having to purchase replacement tubes and iron and whatnot. I have one big advantage in that i'm working as an electrician in a very old foundry and there is discarded equipment on shelves all over the place. There is also a guy who works a lathe who can machine just about any piece i can think of and a pattern shop that has tons of scrap wood if i decide to use that. I think that photos of what i've collected so far is a good idea and i'll post some as soon as i can get a free moment. That might not occur for another 12 hours yet, but i'll get them eventually.
Updated tube haul:
The first list was just the tip of the iceberg:
2x: 12ax7 (one new in box)
8x: 12au7 (in addition to the others)
Most of the rest of these are new in box:
3x: 3B28 (huge!)
2x: 6bg6
1x: 7867
1x: 5751
1x: oa4g
2x: 12bh7a
3x: 12sn7
3x: 12sl7
3x: 12h6
1x: 6av6
1x: 6x4
2x: 12sn7gta
1x: 6sn7gtb
4x: 115n045
3x: ob2
8x: 5u4gb
10x: od3
2x: 6cd6ga
2x: 6aq5a
1x: 6x5gt
The 12ax7 jumps out. I think i remember seeing 5u4gb as well but i'll have to check.
I think it's safe to say that i've got the tubes covered. I've also got more iron than you can shake a stick at and i've got rectifiers and diodes enough to build a bridge circuit if i'd like.
Maybe a dumb question but i need to ask: is there any reason why i couldn't wire any particular 480/120v transformer to transform 120 up to 480? I have never had any professional reason to do so but i can't think of any reason why you couldn't.
I've got many single tap coils (so far) in a range of kva values and at least one transformer from an old 8-track player that i know works and has 3 taps. 6, 12 and 20vac (with a 120 volt input)
The first list was just the tip of the iceberg:
2x: 12ax7 (one new in box)
8x: 12au7 (in addition to the others)
Most of the rest of these are new in box:
3x: 3B28 (huge!)
2x: 6bg6
1x: 7867
1x: 5751
1x: oa4g
2x: 12bh7a
3x: 12sn7
3x: 12sl7
3x: 12h6
1x: 6av6
1x: 6x4
2x: 12sn7gta
1x: 6sn7gtb
4x: 115n045
3x: ob2
8x: 5u4gb
10x: od3
2x: 6cd6ga
2x: 6aq5a
1x: 6x5gt
The 12ax7 jumps out. I think i remember seeing 5u4gb as well but i'll have to check.
I think it's safe to say that i've got the tubes covered. I've also got more iron than you can shake a stick at and i've got rectifiers and diodes enough to build a bridge circuit if i'd like.
Maybe a dumb question but i need to ask: is there any reason why i couldn't wire any particular 480/120v transformer to transform 120 up to 480? I have never had any professional reason to do so but i can't think of any reason why you couldn't.
I've got many single tap coils (so far) in a range of kva values and at least one transformer from an old 8-track player that i know works and has 3 taps. 6, 12 and 20vac (with a 120 volt input)
that chasis you discovered were those valves were mounted could carry some hefty power transformers, because those power tubes you mentioned first can dissipate several watts, maybe that chasis is in fact some kind of power amplifier.
Please upload pictures! we can help you out with those tubes
Please upload pictures! we can help you out with those tubes
Although i am having a great deal of difficulty uploading photos i did eventually clean the chassis enough to find a model number and a builder.
Dukane corp 1a475c mono block amplifier. This link leads to photos of the same model, except that one is a million times less filthy than the one i found.
1A475C Ampl/Mixer DuKane Corporation; St. Charles IL, build
Dukane corp 1a475c mono block amplifier. This link leads to photos of the same model, except that one is a million times less filthy than the one i found.
1A475C Ampl/Mixer DuKane Corporation; St. Charles IL, build
That thing has been a real beast, iron is way too big for your current project ( save it for the 200 watt stage amp you'll wana build down the road). may i suggest you read thru the hundred dollar amp challenge.
http://www.diyaudio.com/forums/instruments-amps/190738-hundred-buck-amp-challenge.html.
these were all around 5 watts built as cheap as possible, you may find just what you need.
http://www.diyaudio.com/forums/instruments-amps/190738-hundred-buck-amp-challenge.html.
these were all around 5 watts built as cheap as possible, you may find just what you need.
Here is a gallery of some of the stuff:
tubes - Imgur
Mostly for your entertainment. I think that I've progressed through most of my first round of questions and I've been using those datasheets to learn some things. I was happy to discover that 6bg6 is essentially identical to a 6l6, which means that I now have 2 of the 3 tubes used in the model 5f1 champ amp schematic. For the other - haven't figured that part out yet. Wondering if the OD3s can fill the bill.
I have spent a little bit of time in the 100 dollar amp challenge and I'll be returning there as soon as I'm done with this post.
I do have some reason to think that it might not be right for me:
1. When forum members describe the characteristics of their creations I have a hard time understanding. I don't yet have a basis for understanding what they have to say. I think I need to start with smaller steps first.
2. I'm not necessarily limited by that budget. I did say that I wanted to make this very cheap, but unless I'm mistaken most of the people who competed in that thread made some attempt to justify the cost of their parts. For me - I don't care so much. I've got 60-70 tubes of various sizes to choose from and there's no reason for me to pick the cheap parts.
That said - I can see that there's a lot that I still need to learn and I have already learned a few things from that.
Thank you everyone. This seems like a very pleasant community.
tubes - Imgur
Mostly for your entertainment. I think that I've progressed through most of my first round of questions and I've been using those datasheets to learn some things. I was happy to discover that 6bg6 is essentially identical to a 6l6, which means that I now have 2 of the 3 tubes used in the model 5f1 champ amp schematic. For the other - haven't figured that part out yet. Wondering if the OD3s can fill the bill.
I have spent a little bit of time in the 100 dollar amp challenge and I'll be returning there as soon as I'm done with this post.
I do have some reason to think that it might not be right for me:
1. When forum members describe the characteristics of their creations I have a hard time understanding. I don't yet have a basis for understanding what they have to say. I think I need to start with smaller steps first.
2. I'm not necessarily limited by that budget. I did say that I wanted to make this very cheap, but unless I'm mistaken most of the people who competed in that thread made some attempt to justify the cost of their parts. For me - I don't care so much. I've got 60-70 tubes of various sizes to choose from and there's no reason for me to pick the cheap parts.
That said - I can see that there's a lot that I still need to learn and I have already learned a few things from that.
Thank you everyone. This seems like a very pleasant community.
I hate to break it to you, but it looks like either one of your 6bg6s or one of your 7867s is dead, judging by the picture (couldn't tell the type from the picture, but something with a plate cap). A tube with a white getter has gone gassy and is of no use. No matter, as these tubes are relatively cheap if you want a replacement. You've still got plenty of good stuff to work with!
Considering you already have a complete amp, although presumably with some issues, the best/fastest/most practical way to go is to first repair it !!!
Plus classic PA amps are KILLER harp and raw guitar sounding amps.
Think White Stripes and their Silvertones and you won't be far from that.
And once it's working you can mod it with Fenderish tone stacks, etc.
Replacing a few resistors and caps with new "same value" in an amp which was already working is by far the shortest path.
Otherwise you'll have to decide on what to build from scratch (besides chassis/iron/sockets), design some layout (form factor won't let you mount a long thin Twin board, for example) , etc.
Of course, clean/vacuum/wipe it well before getting inside
You'll definitely have to replace PSU main caps, the bad tube, etc.
If you find it too much work for a first amp, fine, leave it aside, practice building a Champ or AX84 with other parts (don't cannibalize it ) and in the future return to it.
Plus classic PA amps are KILLER harp and raw guitar sounding amps.
Think White Stripes and their Silvertones and you won't be far from that.
And once it's working you can mod it with Fenderish tone stacks, etc.
Replacing a few resistors and caps with new "same value" in an amp which was already working is by far the shortest path.
Otherwise you'll have to decide on what to build from scratch (besides chassis/iron/sockets), design some layout (form factor won't let you mount a long thin Twin board, for example) , etc.
Of course, clean/vacuum/wipe it well before getting inside
You'll definitely have to replace PSU main caps, the bad tube, etc.
If you find it too much work for a first amp, fine, leave it aside, practice building a Champ or AX84 with other parts (don't cannibalize it ) and in the future return to it.
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Considering you already have a complete amp, although presumably with some issues, the best/fastest/most practical way to go is to first repair it !!!
Plus classic PA amps are KILLER harp and raw guitar sounding amps.
Think White Stripes and their Silvertones and you won't be far from that.
And once it's working you can mod it with Fenderish tone stacks, etc.
Replacing a few resistors and caps with new "same value" in an amp which was already working is by far the shortest path.
Otherwise you'll have to decide on what to build from scratch (besides chassis/iron/sockets), design some layout (form factor won't let you mount a long thin Twin board, for example) , etc.
Of course, clean/vacuum/wipe it well before getting inside
You'll definitely have to replace PSU main caps, the bad tube, etc.
If you find it too much work for a first amp, fine, leave it aside, practice building a Champ or AX84 with other parts (don't cannibalize it ) and in the future return to it.
Yeah i'm trying to leave that intact. 4 of the power tubes - 7867 iirc - were installed in that and had been used. That includes the bad one that i shared a picture of. I wasn't sure why i took that photo tbh but i'm glad i did.
So i think that it would take quite a bit of effort to get that mono amp running again. I would be willing to bet that i'll need 3 more of those tubes and i am skeptical about every capacitor.
I think i have more than enough pieces to put together a champ. I have a champ 600 schematic that uses a solid state bridge instead of the filter tube. I have a 12ax7 and the 6bg6 which supposedly can stand in for a 6v6.
About the iron:
So i have a vast array of transformers to choose from but none have a center tap. They're also specifically 480/240 to 240/120 (for the most part). We have 480 volt busses here at my shop and so we're usually tapping 120 volts for lights and whatnot off of those.
Can i make those work for me? I don't want to have a noisy amp if i can help it.
The good news is that i've got my pick of kva ratings. I've got tons of .050 and ,075s, and some bigger and smaller ones as well. I was thinking i could up my 120 to 480, rectify it and then create a voltage divider to get the specific dc voltages. I've even got some cool resistor bank style resistors that can be tapped in multiple places.
The question of iron is moot. There are plenty of transformers that suit my needs but they're pretty heavy. I don't need .075 kva transformers.
I plan to see a builder this weekend about having some of these vacuum tubes tested, so I will also try to barter some tubes for a power transformer as suggested.
I am pleased to have found a full bridge rectifier that'll do nicely. 600 volt. 100 watt rating and it's the size and weight of a checkers piece.
I plan to see a builder this weekend about having some of these vacuum tubes tested, so I will also try to barter some tubes for a power transformer as suggested.
I am pleased to have found a full bridge rectifier that'll do nicely. 600 volt. 100 watt rating and it's the size and weight of a checkers piece.
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