• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Tube amp wattage?

P

PZapdos

Jan 23, 2010
295
2
New Hampshire
#1
Ok, so im looking into building my own tube amp (with my brother who's not very knowledgable on tube amp to speaker amp wattage but has built a few tube amps for headphones and has a TON of experience with this kinda stuff.


anyway - I was wondering, if i wanted to run a 200 watt cab, how many tube watts should I need?

thanks a lot :]
 
#2
If you don't even understand the basics of tube amp design, and from your question, it's pretty apparent that you don't, then just steer clear of it. Preamp tube-based headphone amps are one thing. A 200W tube bass amp is a serious project, and there's any number of ways you could literally get killed from the build, so, for your own sake, just don't do it.
 
#4
TrooperFarva said:
If you don't even understand the basics of tube amp design, and from your question, it's pretty apparent that you don't, then just steer clear of it. Preamp tube-based headphone amps are one thing. A 200W tube bass amp is a serious project, and there's any number of ways you could literally get killed from the build, so, for your own sake, just don't do it.
Click to expand...

nono not 200w tube amp, i mean an amp that will drive a 200 watt cabinet
 
#5
You can drive a cab rated for 200 watts (electrical thermal rating) with a 5 watt tube or solid state amp the question is how loud you want to be? The more watts you want to send in the cab the greater the risk to you in the build of the amp and usage of that home brew amp. SEE post 2! Not trying to be a jerk, it is a dangerous project that requires training, schooling and experience even for a modest 50 watt tube amp.
 
#6
I'm not using this for gigs, only recording and at home use. I don't gig, so the loudest i would need is "Hey im going to play kinda loud cause im bored" volume. No need for craziness.


also - i realize the dangers, i did all the other research im just wondering about tube amp to a bass cabinet translation, since i couldnt find it through research really.
 
#7
Here are a few links to study before you build your amp. Be safe, not sorry.
Kendrick Amps-amp building seminars/dvds,etc
Hoffman Amps info/forum/parts
Building a tube amp

I have a c.1970 ~30watt 1x15 Alamo Fury. It's plenty loud for home. I've used an '82 active Ibanez Musician bass with it. Played very lightly. Gets plenty loud enough and stays clear if you don't pound on it.

JimmyM used to gig with a 25 watt, two 1x15 cabs Ampeg B15 with PA support.

Here's an example of the Alamo: [Invalid or Expired Link Removed]


Probably cheaper just to buy something like this. The unit is 26” /19 ½” & 9 ¾” deep.
 

Attachments

  • alamo.jpg
    alamo.jpg
    8.8 KB · Views: 62
#8
The amp supplies power, the cab receives that power and changes it into mechanical movement to make sound. That is the relationship between them, tube or solid state. Your needs I'm thinking 30-50 watts, that would at least give you the chance to play with others so long as they are not into peeling paint.
 
#9
oh also - I've built computers with 1600 watt custom built (by me) AC current (more dangerous) PSU's (power supply units)

those are only 12v but thats a LOT of amps, and that will probably kill you pretty quickly.

I'm not dealing with nearly that much with the size tube amp i'm looking at.

I have the skill (as does my brother), just not basic tube amp knowledge


B-string said:
The amp supplies power, the cab receives that power and changes it into mechanical movement to make sound. That is the relationship between them, tube or solid state. Your needs I'm thinking 30-50 watts, that would at least give you the chance to play with others so long as they are not into peeling paint.
Click to expand...

ok, i was just wondering if theres a general "equation" for it. The only thing i heard was that 50 watts of tube = approx 150 watts of solid state, but that seemed very rough, and was hoping for a bit more of a detailed response from the smarts floating around on this board ;)


this is an idea of what i was thinking, its about 25 watts without distortion (a little at 30, from his testing)

http://diyaudioprojects.com/Tubes/KT88-Push-Pull-Tube-Amp/
 
#10
PZapdos said:
those are only 12v but thats a LOT of amps, and that will probably kill you pretty quickly.
Click to expand...

Resistance of human body is about 500 ohms, give or take. Ohms Law?

PZapdos said:
And we all know voltage does not = deadliness,
Click to expand...

Voltage plus low source impedance does, though. Ohm's Law again.

I strongly suggest you do a couple of headphone amps and a solid-state amp first before diving in to a big tube amp project. You'll learn stuff each time that will make the next step easier and more successful. Trying to do everything at once is likely to result in frustration.
 
#11
PZapdos said:
ok, i was just wondering if theres a general "equation" for it. The only thing i heard was that 50 watts of tube = approx 150 watts of solid state, but that seemed very rough, and was hoping for a bit more of a detailed response from the smarts floating around on this board ;)
Click to expand...

2 to 1 is a fair rule of thumb, but we're getting into subjective territory here.
 
#12
Hope you are around to say that after 500 volts charges a couple hundred mf of power supply caps. First lesson the higher voltage the further an arc will travel and you WILL be starting with AC line voltage through a STEP-UP transformer. After you increase the AC voltage from the wall you then rectify it to high voltage DC. The high voltage DC then gets filtered. Are you starting to get the picture?
High voltage AC - High Voltage DC - filtered with a current reserve stored in electrolytic caps. No its not dangerous at all ;)
 
#13
B-string said:
Hope you are around to say that after 500 volts charges a couple hundred mf of power supply caps. First lesson the higher voltage the further an arc will travel and you WILL be starting with AC line voltage through a STEP-UP transformer. After you increase the AC voltage from the wall you then rectify it to high voltage DC. The high voltage DC then gets filtered. Are you starting to get the picture?
High voltage AC - High Voltage DC - filtered with a current reserve stored in electrolytic caps. No its not dangerous at all ;)
Click to expand...

wasnt saying it wasnt, just saying ive dealt with deadly electricty safely before.

thanks for everyone worrying about me, but only got my answer after a bunch of replies, i guess.
 
#14
PZapdos said:
ok, i was just wondering if theres a general "equation" for it. The only thing i heard was that 50 watts of tube = approx 150 watts of solid state, but that seemed very rough, and was hoping for a bit more of a detailed response from the smarts floating around on this board ;)
Click to expand...

Nope - 50 W non-distorting amp of any kind = 50 W non-distorting amp of any kind.
Assuming they have the same frequency response, and sensitivity to the signal you feed them.
 
#16
That project would be a nice HiFi amp. You will need a preamp to drive it. Don't look to the HiFi world for a preamp. You would want to copy a classic Ampeg, Fender preamp and tone stack.
As far as tube vs SS watts.......watts are watts! Tubes still sound pleasing when over driven. Distortion is precieved as loudness, SS overdriven can sound like fingernails on a chalk board.
But WATTS are WATTS. :)
 

Latest posts

Top Bottom
Back