DIY VALVE AMP HELP

[brennyE]

Hey all,

just yesterday before school let out my systems and technology teacher told us that next year ( year 12) our class will be building individual projects, and have the whole year to build them! also since the holidays have just started I have about eight weeks to study the theory I need to know on the particular project I choose. So since I have a pair of RF-82's slowly on the way (supermarket wages suck) I would love to get into building a tube amplifier to use in conjunction with the RF-82's for listening to slow rock etc, instead of using the rather large pair of mono block amplifiers that I have. So this brings me to my question...... Has anyone had any experience in the area of valves? building valve amplifiers, valve theory etc. I am very much open to suggestions to which valves etc I should use in the design and would very much appreciate any references to usefull information on the web. I have basic skills in electronics having built lots of IR remotes, many small electronic "projects" and my two Studio 350 mono block amplifiers with matching power supply.

Look forward to hearing from you all!

Brendan,

[Guest " "]

There are plenty of available schematic's

http://www.geocities.com/TimesSquare/1965/project.html

[brennyE]

thanx []

[ben.]

This would likely be too expensive to amass the parts, but would be poetic as its designer is moving to Perth soon.

I think the general concept should be one of choosing a relatively simple design - not for ease of construction but more for the fun of swapping out components down to road to discover the sonic differences they yield.

[ben.]

Do you have to design it or just build it?

[Painful Reality]

This would likely be too expensive to amass the parts, but would be poetic as its designer is moving to Perth soon.

I think the general concept should be one of choosing a relatively simple design - not for ease of construction but more for the fun of swapping out components down to road to discover the sonic differences they yield.

It can be built for relatively cheap if using Hammond OPT.

I may take your advice and buy an old Ampeg B18 to bring with me. I've spot one that was not to far from my place. I guess it would be a nice mathc with my Rickenbacker 4001.

[ben.]

Hadn't thought of anything but the MQ - good point.

B18? oohey. I've never seen the 18. Either that or the 15 are like the proverbial hens' teeth down there, so bring with if you don't want to go without!

I've been using mine for recording w/ 350B in the outputs and RCA red base 5692 (or whatever the number is - 6SL7).

Everything sounds great through it. The StingRay5 - the G&L p-bass - the cheapy mexican jazz I picked up recently. I run harp through it for some dirt rather than using a crap mic. It does a mean SRV tone with a Strat if you dime all the knobs, too... I'm certain the Ric would sound fantastic.

Just today I pulled the square magnet CTS woofer out in favor of a JBL 2226H. Haven't heard it yet, though... probably bring it along next weekend for the trio thing. It's lighter now, too...

[WMcD]

Brendan,

Let me suggest that you do not build a better amplifier as your class project. Find something else which is oddball if related to another area of science.

Granted this may be your interest. Your science teacher may be impressed with 1 watt amp and give you an "A". He likely is not going to be more impressed with a 10 watt amp and give you a 10 times A. The grade structure doesn't work that way.

I'm speaking somewhat of an older guy. Educational systems are industrial. Sometimes you find a nich.

Right now you're standing at the cusp between what we in the States call high school and college. I assume you're applying for college. If you do a common audio project here, you could be branded as just another kid making a louder stereo.

At one time I was on speaking terms with people who made admissions decisions to higher education. Not that I know much. There are those applicants who make the cut off numbers. But they are pretty much the same type. Above average grades from above average programs.

It seems to me that your future interests would be better served by branching out a bit. Biology, space, anything but pure head banging audio.

You probably have some side interests. Let me suggest that you apply your electronic interest to those in your class project. That way you'll not be just the kid with the big stereo. You could discuss this with the school system. There is some chance there is an oddball teacher hidden in back room who will mentor you.

Best,

Gil

[leok]

Brendan,

A good, and easily read reference is: "Valve Amplifiers" 2nd edition, by Morgan Jones.

Publisher: Newnes

ISBN 0 7506 4425 7

Leo

[brennyE]

Thank you all for your responses! exactly what i was after!

lots of very useful information and ideas ( especially the seth PP2A3 for which the document was a great read)

just to clarify I can spend around AUS$1200 on parts for the amplifier.

And no the amplifier does not have to be of my design, but if I do use someone elses

design I still have to write around six-thousands words on it for the design folio,

so i would still have to learn how everything works!

Thanks everyone, keep the suggestions coming!

Brendan,

[Erik Mandaville]

Brendan:

A Beginner's Guide to Tube Audio Design, by Bruce Rozenblit, is also quite good.

Both the 'Seth' and earlier 'Horus' amps would be excellent for a first-time amp project, and there are other good designs with easy-to-read schematics. As it's designer (Painful Reality) mentioned above, it could be built with less expensive parts, and you would still end up with a truly outstanding amplifier. As designed, it consists of two monoblocks, but it could just as easily be built as a single stereo amplifier.

For a couple of additional designs, also see: Angela Instruments www.angela.com

Scroll to: The How To section

There you'll find some other well done schematics/descriptions of possible designs.

This sounds like great project.

Erik

[brennyE]

Thanks Eric, will look into it now []

[Marvel]

While I agree with Gil some, I think that building a tube amplfier won't make you appear as another headbanger. Especially if a part of what you write on how it works gets into the reasons some people like tube amps.

In other areas, you could learn about three phase moter controllers, steppers for CNC machines, and similar projects. It would fit into more of a career path if so inclined.

[brennyE]

being a begginer to tubes, can anyone please give my a couple of recommendations

for tubes that would suit my application? Would be very much appreciated!

I have heard good things about the 12AX7?

[brennyE]

I did think building another amplifier for a school project (this year it was 2 big solid states) would get me poor marks and a not so happy teacher, after running the idea past him he thought it was a great idea that was very different and would require a new learning perspective. I think he also thinks its a good idea because he would learn something as well, because he knows about as much about valve theory as me []

I am also somewhat a teachers pet in electronics as this year whilst building my amplifier , others in the class built ipod chargers, electronic dice and a led light with switch []

[nicks sig]

Brendan,

Let me suggest that you do not build a better amplifier as your class project. Find something else which is oddball if related to another area of science.

Granted this may be your interest. Your science teacher may be impressed with 1 watt amp and give you an "A". He likely is not going to be more impressed with a 10 watt amp and give you a 10 times A. The grade structure doesn't work that way.

I'm speaking somewhat of an older guy. Educational systems are industrial. Sometimes you find a nich.

Right now you're standing at the cusp between what we in the States call high school and college. I assume you're applying for college. If you do a common audio project here, you could be branded as just another kid making a louder stereo.

At one time I was on speaking terms with people who made admissions decisions to higher education. Not that I know much. There are those applicants who make the cut off numbers. But they are pretty much the same type. Above average grades from above average programs.

It seems to me that your future interests would be better served by branching out a bit. Biology, space, anything but pure head banging audio.

You probably have some side interests. Let me suggest that you apply your electronic interest to those in your class project. That way you'll not be just the kid with the big stereo. You could discuss this with the school system. There is some chance there is an oddball teacher hidden in back room who will mentor you.

Best,

Gil

Hey Brenny!

First up, Seems like Gil does have a point there... school is school; dont forget that in-order to meet the criteria there is also the need for a mechanical aspect... and high marks wont be awarded unless both are met substantially... (former year 12 student from this school =])

then again... if this can be pulled off via. building the amp.. sounds great to me!

Keep us updated with the progress....

Nick.

[brennyE]

hey nick! good to see ya []

I will end up implementing some kind of whacked out mechanical side to the amplifiers

bulk. the question is what??? probably a sliding window to hide the display. for the photonics side a display and IR remote will be made. ( mixing old school with new tech )

[DrWho]

Are you impartial to tube amps? The reason I ask is because there are

some really cool digital amp designs out there that you might want to

consider. And once you start to understand how they work you might even

find yourself designing your own - though I suppose the same could be

argued for tubes too.

There are a few forum members who are really into building their own

tube amps. I think it would be real cool if you could help with the

building a of a new prototype that they're working on. I would argue

that the largest amount of engineering happens during the verification

stage. Things that look good on paper rarely sound good in their raw

form - which means it's going to take a lot of extra work to bring the

raw design into something that actually performs well. I couldn't think

of a more educational experience than another seasoned engineer helping

you along the process. Heck, you might even be able to provide some new

perspectives on the design if you're dedicated enough. Of course this

all requires one of them "old guys" to volunteer their time and designs

[]

[SET12]

Hey all,

just yesterday before school let out my systems and technology teacher told us that next year ( year 12) our class will be building individual projects, and have the whole year to build them! also since the holidays have just started I have about eight weeks to study the theory I need to know on the particular project I choose. So since I have a pair of RF-82's slowly on the way (supermarket wages suck) I would love to get into building a tube amplifier to use in conjunction with the RF-82's for listening to slow rock etc, instead of using the rather large pair of mono block amplifiers that I have. So this brings me to my question...... Has anyone had any experience in the area of valves? building valve amplifiers, valve theory etc. I am very much open to suggestions to which valves etc I should use in the design and would very much appreciate any references to usefull information on the web. I have basic skills in electronics having built lots of IR remotes, many small electronic "projects" and my two Studio 350 mono block amplifiers with matching power supply.

Look forward to hearing from you all!

Brendan,

Brendan,

I can't imagine any real

obstacles to building a great tube amp, I lost my job after a plant closing so I elected to go back to school at the age of 46 for an Associate Degree in Electronics Technology. I used my tube electronics and speaker crossovers for school projects not only for my electronics classes but even for a written communications class! I even demonstrated my whole system to the Communications class for a paper that I wrote "The Joy of Vaccuum Tube Audio" They loved it! I choose the Titanic soundtrack of which afterwards a couple of young guys asked where my sub woofer was? Of course I replied I have none! They where even more shocked at the fact that I was using just 10 watts! In my paper I covered the movie industry history of the use of the Western Electric Model 91 300B amplifiers and an article on how to build one from scratch! Needless to say I got an "A" from that class.

My one of my Electronics instructors even developed an elective course credit for my crossover project which I had to document the crossovers performance and demonstrate it.

I have a pair of Forte's rated at 98db/watt like your RF82's rated the same!

[ben.]

You could implement remote control motorized volume controls...