Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Fresh_Start on July 01, 2010, 09:47:51 am

Title: Eclectic Reference
Post by: Fresh_Start on July 01, 2010, 09:47:51 am: Here's an electronic "book" Merlin posted a link to over on AX84.com:
Designing Vacuum Tube Amplifiers (https://acrobat.com/#d=UjgTcfpvfqvboIiQLKn5rQ)
Please note that it's a weird link. The first page to show up says "Acrobat is Loading" but the book shows up eventually. If anyone knows a better way to link to the document, please have at it.

A really quick skim through revealed a brief history of vacuum tubes, the author's background as a jazz guitarist and retired EE, basic tube circuit theory, amp design approach, test equipment, guitar setup, speaker comparison and much more.

I figure that if it has Merlin's seal of approval it can't be all wrong :wink: There are plenty of interesting opinions (e.g. re-capping an amp is voodoo) along with what appear to be good explanations of how to use tube data sheets, etc. (I'm not qualified to argue with any of it.)

Anyway, please let me know if this is a useful reference so I can add it to the "sticky" if it is. In any event, it's a hell of a lot of work this guy has offered to all of us for FREE.

Cheers,

Chip
Title: Re: Eclectic Reference
Post by: simonallaway on July 01, 2010, 10:36:14 am: I'm 16 pages in and enjoying it. It's got some fascinating history/background.

I didn't realise that the need to rebias output tubes is not only a recent thing, but due to inconsistent manufacturing of tubes.

Thanks for destroying any chance of me writing any useful code at work today :wink:
Title: Re: Eclectic Reference
Post by: Geezer on July 01, 2010, 01:16:04 pm: Thanks Chip........I downloaded a copy to my hard drive for easier access in the future.

G
Title: Re: Eclectic Reference
Post by: jojokeo on July 01, 2010, 01:35:49 pm: Very Cool - thanks Chip
Title: Re: Eclectic Reference
Post by: jjasilli on July 01, 2010, 03:08:06 pm: Quote from: Geezer on July 01, 2010, 01:16:04 pm
Thanks Chip........I downloaded a copy to my hard drive for easier access in the future.

G
Quote from: jojokeo on July 01, 2010, 01:35:49 pm
Very Cool - thanks Chip

DITTO!
Title: Re: Eclectic Reference
Post by: Rev D on July 01, 2010, 07:27:18 pm: Gracias, downloaded and perusing as we speak.

Regards,

D.
Title: Re: Eclectic Reference
Post by: RicharD on July 01, 2010, 09:16:36 pm: Thanks for the link. His diagrams were drawn with CircuitMaker and that made me smile.
Title: Re: Eclectic Reference
Post by: PRR on July 01, 2010, 11:36:26 pm: Sticky it.

I see some personal opinion, and a few things which I would say differently, but overall an impressive work. He knows his stuff.
Title: Re: Eclectic Reference
Post by: Fresh_Start on July 02, 2010, 08:29:00 am: Quote from: PRR on July 01, 2010, 11:36:26 pm
Sticky it.

I see some personal opinion, and a few things which I would say differently, but overall an impressive work. He knows his stuff.

Yes sir!
Title: Re: Eclectic Reference
Post by: HotBluePlates on July 02, 2010, 11:30:12 am: Well, I think I found the source of the book over on the PlayJazzGuitar forum. I was reading ~~this link~~ (http://www.playjazzguitar.com/forum/viewtopic.php?t=4982) to try and download the spreadsheets mentioned, however, I can't access them. EDIT: Same guy, newer post, newer link (http://www.playjazzguitar.com/forum/viewtopic.php?t=5100), however the download link has expired. Maybe if we ask randyc nicely, he'll make the spreadsheets available again some way.
Title: Re: Eclectic Reference
Post by: Fresh_Start on July 02, 2010, 02:50:45 pm: I'm in the registration process at PlayJazzGuitar.com and will ask RandyC as politely as possible if he can make the Excel workbook available to us some way or another.

Thanks for finding the link HBP!

Happy Independence Day Weekend to All!!!

Chip
Title: Re: Eclectic Reference
Post by: HotBluePlates on July 03, 2010, 10:46:01 am: I read some of the book in detail and scanned other parts. After basically finishing it, I find it impressive that he wrote it all out.

I disagree with some of his views on screen voltage, and believe I have some solid technical reasoning and examples to back my perspective. But wow... Mr Couch did a great job!
Title: Re: Eclectic Reference
Post by: Fresh_Start on July 05, 2010, 09:45:10 am: The author, Randy, has been kind enough to give me permission to post a link to the Excel workbook HERE (http://www.webfilehost.com/?mode=viewupload&id=7911796)

Please note that you have to wait 60 seconds before the download is available. Scroll down and look over to the right to find the timer and appropriate button in a grey box for the Excel workbook download. Whether you look at the ads during that time is your personal choice :wink:

Please note that Randy added the following:
Quote
A few words of caution: the spreadsheets are not protected so it's possible to inadvertently over-write some of the calculations. (My practice is to use blue text to indicate user entries.) Also, since the spreadsheets were devised for personal usage, no particular care was used to make them friendly to others.

Randy also asked me to send him a reference to where I posted the links. He is interested in any feedback on the book. If you ask me, we would be really lucky to have him join our community here.

Cheers,

Chip
Title: Re: Eclectic Reference
Post by: HotBluePlates on July 21, 2010, 07:59:59 pm: Quote from: Fresh_Start on July 05, 2010, 09:45:10 am
If you ask me, we would be really lucky to have him join our community here.

Cheers,

Chip

I couldn't agree more. I've read a number of his posts on amps/electronics on the jazz guitar forum, and he has some excellent and well-executed ideas. A definite wealth of knowledge that would be an asset in any electronics discussion!