As we bassists are constantly in search for the perfect tone, I decided to devote my Engineering project in school to building a tube amp head. I want to build a hybrid amp, A tube pre-amp with a solid state power amp. I have an Ampeg SVT wiring diagram for the tube pre-amp, but not only would I like to customize that a bit more, I also don't have a diagram/schematic for the power amp. My pre-amp design should go something like this. A gain control, a bass control with a sub switch for an extra bass boost, a 5 channel Graphic EQ for the mids, a treble control with a bright swith, and a master volume knob. For power amp, I know i want a FX loop and Speak-on out puts, and maybe one 1/4'. If anyone can help me with this intense project, that would rock!! So, any takers?
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Building my own Tube head
- Thread starter bassplaya92
- Start date
Passinwind
I know nothing.
- Dec 3, 2003
- 23,065
- 45,981
- Disclosures
- Designer/Toaster Tech @ Passinwind Electronics
I'd suggest that you use an off the shelf power amp module. You are already biting off a lot with the required multi-voltage power supply it's going to take to make your design configuration perform optimally.
How about detailing your prior DIY build experience? And probably most importantly: what's your budget?
How about detailing your prior DIY build experience? And probably most importantly: what's your budget?
So an off the shelf power amp is what I need? I'm kinda new at power amps, so how does that work? My DIY expierence doesnt have much to do with amps, but I've wired all my engineering projects including a Smart Home security system, a Flexible manufacturing system, and a robotic can crusher. Also, my budget is probably going to be in the $300 or less range.
get some excellent life insurane for when you accidentally discharge a capacitor into your system.
oh, and you won't buy even a halfway decent output transformer for under $300 by itself,let alone a quartet or sextet of matched power tubes...
oh, and you won't buy even a halfway decent output transformer for under $300 by itself,let alone a quartet or sextet of matched power tubes...
that's probably why he's building a hybrid, so he won't need a big old output transformer nor any power tubes.
Missed that part when I saw "Ampeg wiring diagram, svt"...sorry.
Still not gonna be able to do it for 300 bucks. Just my opinion. I would just build the preamp, for whatever the cost, and use a seperate rackable power amp.
My Senior Design Project for my EE degree was a tube amp. $300 dollars is a pretty slim budget and I think I actually ended up spending a lot more than that. I think I may have spent $200+ on the iron (power and output tubes).
As far as resources, there are a few good websites with projects (AX84.com), but as a suggestion ... start as simple as possible to get the basics down and move on from there. Simple also usually means low power, but again if you outsource the power amp you have some options.
There are a few books that give some good basics for tube stuff that I found useful ...
London Power Press -- Tonnes of Tone and Invalid Link Removed
RCA Receiving Tube Manual -- Invalid Link Removed carries this one
As far as resources, there are a few good websites with projects (AX84.com), but as a suggestion ... start as simple as possible to get the basics down and move on from there. Simple also usually means low power, but again if you outsource the power amp you have some options.
There are a few books that give some good basics for tube stuff that I found useful ...
London Power Press -- Tonnes of Tone and Invalid Link Removed
RCA Receiving Tube Manual -- Invalid Link Removed carries this one
You could go for a Class-D for the poweramp part, company's like http://www.hypex.nl/ sell great kits and the advantage is that is doesn't get so heavy and big and can still deliver massive amounts op power.
Ok thanks guys. This is actually for my High School Senior engineering project, and i think i'm just going to start simple, and build something like a fender bassman amp. Does anyone know the price for something like that?
Sure, I'll help.
You go party and chase tail with your frat buddies and I'll design and build it. Just post the required completion date and an address to ship it to.
You go party and chase tail with your frat buddies and I'll design and build it. Just post the required completion date and an address to ship it to.
Keep it simple. If you have to design something, start small with something like a solid state preamp or effects pedal. It's early in the year, so if you breeze through, you should have plenty of time to go larger.
If you just have to build something, you could build a tube amp kit from Link Removed.
Either way, take your time and keep everything neat. Try to only get shocked through one limb at a time.
If you actually want to make money later in life, give up on tube amps and study digital signal processing (DSP).
If you just have to build something, you could build a tube amp kit from Link Removed.
Either way, take your time and keep everything neat. Try to only get shocked through one limb at a time.
If you actually want to make money later in life, give up on tube amps and study digital signal processing (DSP).
Without prior high voltage experience your high school project could be your last. Even the Fender Bassman has lethal voltages residing within it. my I seriously suggest something like a Fender Champ. Much kinder voltages and a simple circuit. As tube electronics in no longer a classroom subject you are going to have to learn as you go. You also could do with a knowledgeable mentor. This is not something for a neophyte to consider. Even the AC line voltages have to be handled correctly and to code for safety.
Paul
Paul
Probably the simplest amp you could build would be something along the lines of a Fender Champ.
For a Fender Bassman, just looking at the transformers (Power and Output) you're going to spend about $150 with $65 for the Output Tranny and $90 for the Power Tranny. This is the price on Angela Electronics
Then you need to spend cash on tubes which will run you another couple hundred bucks the enclusure and the price to get it routed if you don't have Greenlee Punches and Nibblers.
Based on your current experience, it may be best to start out with a kit in your price range.
This site has a Champ Kit (head only no cabinet) for $239. They actually have a [Invalid or Expired Link Removed] which is $620 for all the parts and the prepunched enclosure.
Seems a bit ambitious for a high school project plus a budget of $300 won't get you very far. I would suggest instead building something like a tube direct box. It would be a much more manageable circuit to build. Breadboarding a design and dialing in the component values (once it actually works) can be a major pain even for small circuits.
Pick up ltspice - free
Link Removed
Pick up tube amp spice models here - free:
http://www.duncanamps.com/technical/ltspice.html
6bq5_5w_amp.zip
el34_push_pull.zip
Just unzip and drop them into the ltspice examples directory.
Start up ltspice and load one in.
Click the little running man - and then click on the "Load" tab - you'll see the output waveform.
Search and read all the FAQ's on ltspice - you can play with the circuits, vary the voltage, you can even set it so the tubes have to warm up - see the duncan amp page.
You can also use a wave files - such as a recording of your bass an an input.
This will at least give you a way to safely learn about tubes.
The tube models are accurate.
You'll get a lot more mileage in life learning Spice over learning tubes.
Link Removed
Pick up tube amp spice models here - free:
http://www.duncanamps.com/technical/ltspice.html
6bq5_5w_amp.zip
el34_push_pull.zip
Just unzip and drop them into the ltspice examples directory.
Start up ltspice and load one in.
Click the little running man - and then click on the "Load" tab - you'll see the output waveform.
Search and read all the FAQ's on ltspice - you can play with the circuits, vary the voltage, you can even set it so the tubes have to warm up - see the duncan amp page.
You can also use a wave files - such as a recording of your bass an an input.
This will at least give you a way to safely learn about tubes.
The tube models are accurate.
You'll get a lot more mileage in life learning Spice over learning tubes.
Seems some people have yet to actually read the original post...he wants to build a HYBRID amp- tube preamp and solid-state power amp. Much less likely to completely fry himself, though still time-consuming and potentially expensive...
The OP has ventured here for advice, and he certainly received that and more. May have missed the part where there was something to be gained from talking him down with unhelpfull comments, though i suppose he may as well learn about the real world at some stage. Well surprised that unhelpfull comments come from Bass Players....we are special people playing special instruments one and all 
).
He is a student with initiative it would seem. The project is bigger than perhaps he is aware, and that is the point, he is not aware as the more experienced eyes here atest. Seamonky suggests a very good starting point, inline with modern design concepts. Paul makes the good point of safety, very important. Hence the mentor if available is a very good process when done with qualified teaching techniques ( teaching properly is not as easy as it looks or made to look ). Others make pertinent comments though are not of direct relevence to the intended project.
Given the level of this students academic situation, and perhaps a desire to do something different ( and be ambitious ) then an effects box based on a single tube ( or twin internal tube ) design may be a more managable project ( as suggested by other poster metron, good advice ). You do not need to run high plate voltages on low power signal circuits like effects. Even a simple SS inverter with simple magnetics could make the project more versatile in learning outcome and reduced danger of lethal power ie with DC-DC convertor. A medium power plug pack ( may drive the tube heater(s) direct ) could run the project. Various signal processing could be included such as distortion or filter efects.
Just a few suggestions, hope your project starts well and finishes well....planing is the key. Regards John.
).He is a student with initiative it would seem. The project is bigger than perhaps he is aware, and that is the point, he is not aware as the more experienced eyes here atest. Seamonky suggests a very good starting point, inline with modern design concepts. Paul makes the good point of safety, very important. Hence the mentor if available is a very good process when done with qualified teaching techniques ( teaching properly is not as easy as it looks or made to look ). Others make pertinent comments though are not of direct relevence to the intended project.
Given the level of this students academic situation, and perhaps a desire to do something different ( and be ambitious ) then an effects box based on a single tube ( or twin internal tube ) design may be a more managable project ( as suggested by other poster metron, good advice ). You do not need to run high plate voltages on low power signal circuits like effects. Even a simple SS inverter with simple magnetics could make the project more versatile in learning outcome and reduced danger of lethal power ie with DC-DC convertor. A medium power plug pack ( may drive the tube heater(s) direct ) could run the project. Various signal processing could be included such as distortion or filter efects.
Just a few suggestions, hope your project starts well and finishes well....planing is the key. Regards John.
+1 on LTSpice. It has a fairly gentle learning curve, but it is definitely not a toy. Along the lines of free goodies, I also recommend looking up Virtual Analyzer, which will turn your computer into a signal generator and scope with features such as spectrum analysis. If you build small-signal circuits, you can follow the signals with the scope and see what is really happening. Of course you can do this in LTSpice too, but there is something real about doing it for real that brings the theory to life.
The OP is wise not to attempt a tube power amp. In my view, unless one is a tube guru, building a tube power amp is merely an exercise in workmanship.
My comments did suggest an all-tube amp. IMHO based on some limited experience building somewhat functional tube amps basically from scratch with only a circuit, an all-tube amp is probably less complex than a hybrid amp.
Officially you could build a single-ended low power tube amp with a single preamp tube and a single power tube (This happens to be the circuit for the Invalid Link Removed).
I was just trying to give the OP some suggestions that would end up with higher probability of success. As far as killing oneself a hybrid amp is equally dangerous. It's high current instead of high voltage.
I would recommend a couple of Kevin O'Connor's book for some practical tube amp knowledge and projects:
Simple tube preamps for guitar and bass, simple tube power amp and other stuff as well:
Invalid Link Removed
Great book if you want to clone or bjild a variant of some of the most iconic tube guitar and bass amps as well as more practical info:
http://www.londonpower.com/catalog/product_info.php?cPath=3&products_id=6
If you want a solid state power amp, I would suggest starting with a chip amp such as the LM3886. Look for simple circuit board level kits and also visit this site for lots of info on chip amp project building:
http://www.diyaudio.com/forums/forumdisplay.php?f=40
You can get something like 50 watts out of one of these and their much more foolproof than building an amp from scratch.
Here's a place that sells kits for these:
Link Removed
Edit: Great place in the states to buy Kevin's books:
http://elderly.com/welcome.htm
Simple tube preamps for guitar and bass, simple tube power amp and other stuff as well:
Invalid Link Removed
Great book if you want to clone or bjild a variant of some of the most iconic tube guitar and bass amps as well as more practical info:
http://www.londonpower.com/catalog/product_info.php?cPath=3&products_id=6
If you want a solid state power amp, I would suggest starting with a chip amp such as the LM3886. Look for simple circuit board level kits and also visit this site for lots of info on chip amp project building:
http://www.diyaudio.com/forums/forumdisplay.php?f=40
You can get something like 50 watts out of one of these and their much more foolproof than building an amp from scratch.
Here's a place that sells kits for these:
Link Removed
Edit: Great place in the states to buy Kevin's books:
http://elderly.com/welcome.htm
