Power Amp

Damon_McC · 7th May 2007, 08:29 PM

Hey,

Im new to the world of Tube amps but not the world of electronics and have been searching and searching for a power amp to add to my preamp. want it to be around 100W.

I have found a few on the web but just wondering what ideas other people have?

Cheers
Damon

ErikdeBest · 7th May 2007, 09:04 PM

Hi Damon

Start telling something about the speakers you have, size of the room, music you listen to. That helps the orientation process!

100W is quite some power involving rather complex and expensive amplifiers - and most of the times not needed! If you tell something about the above, we may speak you into something simpler/cheaper!

Eli Duttman · 7th May 2007, 11:28 PM

Damon,

Erik is very much on target. Please apply Paul Joppa's 102 dB. rule. In a "typical" room an amp/speaker combo should be capable of 102 dB. SPL peaks at a 1 M. distance.

Another thing to keep in mind is that tube power amps tend to have smaller damping factors than SS power amps. If your favorite speakers have significant dips in the impedance curve (particularly in the bass region) they are likely to mate poorly with many tube amps.

Many a good sounding system has been built around tubed preamplification and SS power amplification. Explore the option before you part with hard earned cash.

Edit: fixed typos

sorenj07 · 8th May 2007, 01:02 AM

Quote:

Originally posted by Eli Duttman
If your favorite speakers have significant dips in the impedance curve (particularly in the bass region) they are likely to mate poorly with many tube amps

I guess my Cerwin Vega D7's with their "4-8 ohms" rating fit into that category, eh?

Maybe it's time for a small push-pull triode amp instead of my UL 6L6 monoblocks - triodes have a higher damping factor, right?

Eli Duttman · 8th May 2007, 01:43 AM

Quote:

Originally posted by sorenj07

I guess my Cerwin Vega D7's with their "4-8 ohms" rating fit into that category, eh? Maybe it's time for a small push-pull triode amp instead of my UL 6L6 monoblocks - triodes have a higher damping factor, right?

1st, try the CVs on the 4 Ohm taps. IMO, they are 4 Ohm speakers, in spite of the nominal 8 Ohm claim.

Don't be so quick to give up on UL. A little carefully judged loop NFB takes care of the damping factor issue.

What sort of topology is currently used in the 6L6 amp?

sorenj07 · 8th May 2007, 02:33 AM

They're those Williamsons that I still haven't finished building

Damon_McC · 8th May 2007, 08:14 PM

Hey cheers for the response, been out today so not been around to reply!

All good stuff and cheers.

Im looking to play pretty heavy music, metal/punk hardcore etc.

I love the Ibanez Duel Rectifier sound and would like something along those lines not needing to be 100W however.

Just finised an electronics degree but and want to master making a nice tube amp!

Speakers are standard marshal 4X12.

Damon

Damon_McC · 8th May 2007, 08:55 PM

Im sorry im rather mindless in the fact that i probably should state this shall be a guitar amplfier!

my appologies, ive had a lot on

Regards
Damon

Bandersnatch · 8th May 2007, 09:28 PM

Hey-Hey!!!,
I'd suggest a PP 807 power stage. 10k a-a output with U-L taps at 40%( not 25-35%, but 40 to 43% ). B+ at around 400V will net you close to class a bias and nearly 30W of very nice power. You'll not need any NFB, so the usual gain structure can be played with. 12AY7, or maybe some TV frame grids like the 6BQ7 instead of the 12AX7.
cheers,
Douglas

Damon_McC · 8th May 2007, 10:25 PM

Cheers for that i will look into it!

Being new to this game also im struggling to find suppliers of Power Transformers for the amp. Any good UK suppliers?

Regards
Damon

7th May 2007, 08:29 PM	#1
Damon_McC diyAudio Member Join Date: May 2007	Power Amp Hey, Im new to the world of Tube amps but not the world of electronics and have been searching and searching for a power amp to add to my preamp. want it to be around 100W. I have found a few on the web but just wondering what ideas other people have? Cheers Damon

7th May 2007, 11:28 PM	#3
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	Damon, Erik is very much on target. Please apply Paul Joppa's 102 dB. rule. In a "typical" room an amp/speaker combo should be capable of 102 dB. SPL peaks at a 1 M. distance. Another thing to keep in mind is that tube power amps tend to have smaller damping factors than SS power amps. If your favorite speakers have significant dips in the impedance curve (particularly in the bass region) they are likely to mate poorly with many tube amps. Many a good sounding system has been built around tubed preamplification and SS power amplification. Explore the option before you part with hard earned cash. Edit: fixed typos __________________ Eli D.

8th May 2007, 09:28 PM	#9
Bandersnatch diyAudio Member Join Date: Jul 2003 Location: Ann Arbor, MI	Hey-Hey!!!, I'd suggest a PP 807 power stage. 10k a-a output with U-L taps at 40%( not 25-35%, but 40 to 43% ). B+ at around 400V will net you close to class a bias and nearly 30W of very nice power. You'll not need any NFB, so the usual gain structure can be played with. 12AY7, or maybe some TV frame grids like the 6BQ7 instead of the 12AX7. cheers, Douglas __________________ the Tnuctipun will return

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7th May 2007, 09:04 PM	#2
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	Hi Damon Start telling something about the speakers you have, size of the room, music you listen to. That helps the orientation process! 100W is quite some power involving rather complex and expensive amplifiers - and most of the times not needed! If you tell something about the above, we may speak you into something simpler/cheaper!

8th May 2007, 02:33 AM	#6
sorenj07 diyAudio Member Join Date: May 2006	They're those Williamsons that I still haven't finished building

8th May 2007, 08:14 PM	#7
Damon_McC diyAudio Member Join Date: May 2007	Hey cheers for the response, been out today so not been around to reply! All good stuff and cheers. Im looking to play pretty heavy music, metal/punk hardcore etc. I love the Ibanez Duel Rectifier sound and would like something along those lines not needing to be 100W however. Just finised an electronics degree but and want to master making a nice tube amp! Speakers are standard marshal 4X12. Damon

8th May 2007, 08:55 PM	#8
Damon_McC diyAudio Member Join Date: May 2007	Im sorry im rather mindless in the fact that i probably should state this shall be a guitar amplfier! my appologies, ive had a lot on Regards Damon

8th May 2007, 10:25 PM	#10
Damon_McC diyAudio Member Join Date: May 2007	Cheers for that i will look into it! Being new to this game also im struggling to find suppliers of Power Transformers for the amp. Any good UK suppliers? Regards Damon

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