2Watt_BluesExpress_Version1 by timohp

[ODwan]

Hi,
here are the requested docs!
Have fun and rock!
Timo

[Guy G]

nice, thanks.
What PT did you use with this?

[dayn]

Would this make a good amp for a first attempt at an amp build (with some help from a friend who knows soldering/safety etc.)?

If so, what is the best way to come up with a parts list? Anyone make a "kit" of this amp or a similar low watt trainwreck style amp?

Thanks!

[axpro]

Would this make a good amp for a first attempt at an amp build (with some help from a friend who knows soldering/safety etc.)?

If so, what is the best way to come up with a parts list? Anyone make a "kit" of this amp or a similar low watt trainwreck style amp?

Thanks!

DAYN!!!!!

THis tinywreck should be easy enough to build... but it may be a little wierd to work on for a first project... a 5f1 is my fave 1'st time project... but if you wbere a 5f1 fan you wouldn't be researching wrecks!

[Drumslinger]

thanks ODwan. Should make for a nice little project.

[maxfac]

Hi,
here are the requested docs!
Have fun and rock!
Timo

Hi ODwan
I'm thinking of building the Tiny Tube Express to the design that you posted.
I'm in the U.K where our mains voltage is 235 -245v, is it possible to do away with using a PT completely as the mains voltage is so close, this would cut down the build costs and size considerably, obviously I'd still need to rectify, sorry if this is a stupid question I'm a relative noob at this, I've only built one amp before.

Cheers Andy

[flood]

Hi,
here are the requested docs!
Have fun and rock!
Timo

Hi ODwan
I'm thinking of building the Tiny Tube Express to the design that you posted.
I'm in the U.K where our mains voltage is 235 -245v, is it possible to do away with using a PT completely as the mains voltage is so close, this would cut down the build costs and size considerably, obviously I'd still need to rectify, sorry if this is a stupid question I'm a relative noob at this, I've only built one amp before.

Cheers Andy

hi andy, i'm a noob too, but this is a pretty serious question that you're asking - doing away with the power transformer means doing away with the galvanic isolation that could protect you from shock. in what we (biomedical engineers) call a primary fault condition, you could end up directing the entire wrath of mains voltage onto the chassis or your ground, and there is generally a very high chance of electrocution. a few people have done this sort of thing, but do not recommend it. i would especially not recommend it if you are a beginner, since it is extremely dangerous!

there is a simpler and cheaper way to work around the expensive PT - using two 12V transformers with adequate current resources in a back-to-back configuration. that way, you can use 12V to heat your tubes, and get 230V out of the second transformer for B+. cheers.

[ODwan]

hi andy, i'm a noob too, but this is a pretty serious question that you're asking - doing away with the power transformer means doing away with the galvanic isolation that could protect you from shock. in what we (biomedical engineers) call a primary fault condition, you could end up directing the entire wrath of mains voltage onto the chassis or your ground, and there is generally a very high chance of electrocution. a few people have done this sort of thing, but do not recommend it. i would especially not recommend it if you are a beginner, since it is extremely dangerous!

there is a simpler and cheaper way to work around the expensive PT - using two 12V transformers with adequate current resources in a back-to-back configuration. that way, you can use 12V to heat your tubes, and get 230V out of the second transformer for B+. cheers.

I'll second this! A mainstransformer is an integral part in any tube amps safety! Try that back-to-back transformers or sometimes there are cheap line isolation transformers available. I have used a small transformer from http://www.die-wuestens.de/ that is quite cheap. They chip to GB, too.
Timo

[Doug H]

Looks nice!

I experimented with a low watt 12au7 trainwreck a few years ago. Only I implemented a LTP PI and NFB loop instead. Have you tried anything like that? I wonder how it would compare.

[maxfac]

Hi,
here are the requested docs!
Have fun and rock!
Timo

Hi ODwan
I'm thinking of building the Tiny Tube Express to the design that you posted.
I'm in the U.K where our mains voltage is 235 -245v, is it possible to do away with using a PT completely as the mains voltage is so close, this would cut down the build costs and size considerably, obviously I'd still need to rectify, sorry if this is a stupid question I'm a relative noob at this, I've only built one amp before.

Cheers Andy

hi andy, i'm a noob too, but this is a pretty serious question that you're asking - doing away with the power transformer means doing away with the galvanic isolation that could protect you from shock. in what we (biomedical engineers) call a primary fault condition, you could end up directing the entire wrath of mains voltage onto the chassis or your ground, and there is generally a very high chance of electrocution. a few people have done this sort of thing, but do not recommend it. i would especially not recommend it if you are a beginner, since it is extremely dangerous!

there is a simpler and cheaper way to work around the expensive PT - using two 12V transformers with adequate current resources in a back-to-back configuration. that way, you can use 12V to heat your tubes, and get 230V out of the second transformer for B+. cheers.

Thanks for the heads-up on the safety aspect of my question, I think I'll stick with a PT, my wife and kids would miss me I think ? The thought also occured to me after I'd posted that I'd still need a PT for the heaters so I'd probably not save that much real estate on the chassis anyway.

Andy

[T-diddy]

hi andy, i'm a noob too, but this is a pretty serious question that you're asking - doing away with the power transformer means doing away with the galvanic isolation that could protect you from shock. in what we (biomedical engineers) call a primary fault condition, you could end up directing the entire wrath of mains voltage onto the chassis or your ground, and there is generally a very high chance of electrocution. a few people have done this sort of thing, but do not recommend it. i would especially not recommend it if you are a beginner, since it is extremely dangerous!

there is a simpler and cheaper way to work around the expensive PT - using two 12V transformers with adequate current resources in a back-to-back configuration. that way, you can use 12V to heat your tubes, and get 230V out of the second transformer for B+. cheers.

I'll second this! A mainstransformer is an integral part in any tube amps safety! Try that back-to-back transformers or sometimes there are cheap line isolation transformers available. I have used a small transformer from http://www.die-wuestens.de/ that is quite cheap. They chip to GB, too.
Timo

Sorry I know this is probably a noob, question, but if anybody has a link to a suitable power transformer or part #, that would be great.

Also I know that the wires of a PT are color coded, so how would the different colors fit the numbers listed on the power section layout?

I do alot of work with perfboard and am also wondering if you think I could do the whole layout on perf? Never used turretboards before.

[dorrisant]

did you ever get a transformer?

you could look at just about any of the tube amp parts suppliers and find one. look for a pt for a champ or something small like that... this circuit won't draw many mAs so you don't need much. a decent pt will save you a lot of trouble in the long run 'cause it has the filament voltage as well... and probably won't cost too much either.

i was going to post a link to triode electronics but something seems a little wonkey with their site...

other option... i found an old crescent reel to reel tape player at a flea market. had a complete tube amp with a se 6k6, two siemans preamp tube (sweet!) and an indicator eye tube... all for the awesome price of $5... can't beat it with a stick!

good luck!
tony

[jeremyb]

Anyone got any build pics? I'm tempted to have a crack at one of these, we are 240v in New Zealand as well

[camerongrieve]

Whatever you do, use a power transformer! Use a pair of low voltage transformers back to back, rip one out of an old valve radio..whatever

Otherwise, all it takes is a miswired power point and you could possibly have all 240 of those volts on your guitar strings

[El_Martin]

Anyone got any build pics? I'm tempted to have a crack at one of these, we are 240v in New Zealand as well

Hi there!

see my blues express combo:
http://ampgarage.com/forum/viewtopic.php?t=13456

Enjoy!

Ciao
Martin