Small beginners guitar amp - UK Vintage Radio Repair and Restoration Discussion Forum

amp_mangler · 16th Oct 2010, 1:59 am

Hi all,
A little guitar amp I made up. the pics are from a short text I wrote for newbies to "hand make" it themselves. Original design is from Radio, Television and Hobbies. A now defunct Australian magazine that started in the 20,s and wound up in early 80,s. This design is 1954, sounds superb and is very easy to construct. Chassis is hand made by me, as are transformers and choke.
Choke = 10 H @ 150 mA
Mains = 285 + 285 volts @125 Ma
6.3 volts CT 2A
5.0 volts 2A

Output = 8K CT to 8 ohms

Joe

Diabolical Artificer · 16th Oct 2010, 11:10 am

Thats looks a nice little amp,nice work.And you made the TX,s too.Wow!How many watts?Very tidy job,Andy

mark pirate · 16th Oct 2010, 11:15 am

You have made a great job of that, very proffesional looking

Mark

SeanStevens · 16th Oct 2010, 11:30 am

I want one!

Very nice work.

SEAN

Colin · 16th Oct 2010, 1:29 pm

Really nice job Joe!

fidobsa · 16th Oct 2010, 1:54 pm

Yes, very neat work. Is it destined to go in a speaker cabinet or used as-is?

Herald1360 · 16th Oct 2010, 5:21 pm

Quote:

Originally Posted by magnetic

Wow!How many watts?

Probably around 12- that's typical for these valves in the "data sheet" p-p configuration.

amp_mangler · 16th Oct 2010, 10:29 pm

Yeah, around 12 watts ( I didnt bother measuring it). It goes in a speaker box, a single 12" Alnico from the 60,s ( Akai) seems quite efficient ( d#mn LOUD in other words)
there is one modification I made !!, the volume control has been moved to the triode grid, to allow some overdrive without the 12 watts

Joe

jesusjones · 18th Oct 2010, 4:32 am

Very nice clean layout you have there. I wish my projects looked that sturdy and organized

Cheers,
Andrew

P.S. Wish I knew how to wind my own transformers

kalee20 · 18th Oct 2010, 6:45 am

Nice job, Joe - looks very good, something to be proud of.

Quote:

Originally Posted by jesusjones

Wish I knew how to wind my own transformers

You need lots of blood, sweat, and tears (which you have to keep from contaminating the winding)

.

Aerodyne · 18th Oct 2010, 9:52 am

Craftsmanship of a high order, Joe. You are, I'm sure, justly proud of your quality work.
-Tony

Tim · 18th Oct 2010, 11:13 am

Very attractively built !

An amp constructed like that can only sound good,it wouldn't dare otherwise.

If I had been the designer I would have considered specifiying 6V6's in the original design if the amp was going to get a good hammering.
6BW6's are the same thing of course, but in a B9A envelope. This means they're not so good at dissipating heat and tend to have a short(but fullfilled)life.
12 watts will certainly rattle the windows!

kalee20 · 18th Oct 2010, 12:39 pm

True - but if the chassis is run out in the open, there'll be plenty of cooling. It's mainly miniature valves in close-packed miniature equipment that suffers. (Although yes, I'd have used 6V6's myself, too).

I have been running a pair of 6AQ5's (B7G version of the 6V6 - talk about fitting a gallon into a pint pot), for 24 years now. I used these because (1) I have some, ex-equipment; and (2) the chassis I was using wasn't big enough for octal valveholders. But these also are running out in the open, and are surviving well!

Hybrid tellies · 19th Oct 2010, 9:22 pm

What a nice tidy little job looks so profesional. Bet it can still give a lot of todays smaller guitar amps a run for their money.

chroma04 · 23rd Oct 2010, 8:46 pm

Cracking job!

Want one!!

16th Oct 2010, 1:59 am	#1
amp_mangler Retired Dormant Member Join Date: Aug 2010 Location: Mareeba, Queensland, Australia. Posts: 140	Small beginners guitar amp Hi all, A little guitar amp I made up. the pics are from a short text I wrote for newbies to "hand make" it themselves. Original design is from Radio, Television and Hobbies. A now defunct Australian magazine that started in the 20,s and wound up in early 80,s. This design is 1954, sounds superb and is very easy to construct. Chassis is hand made by me, as are transformers and choke. Choke = 10 H @ 150 mA Mains = 285 + 285 volts @125 Ma 6.3 volts CT 2A 5.0 volts 2A Output = 8K CT to 8 ohms Joe Attached Thumbnails

16th Oct 2010, 11:10 am	#2
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,667	Re: Small beginners guitar amp Thats looks a nice little amp,nice work.And you made the TX,s too.Wow!How many watts?Very tidy job,Andy __________________ Curiosity hasn't killed this cat...so far.

16th Oct 2010, 11:15 am	#3
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Small beginners guitar amp You have made a great job of that, very proffesional looking Mark

16th Oct 2010, 11:30 am	#4
SeanStevens Octode Join Date: Sep 2009 Location: Bath, Somerset, UK. Posts: 1,033	Re: Small beginners guitar amp I want one! Very nice work. SEAN __________________ There are only 10 types of people, those who understand the binary system, and those who don't.

16th Oct 2010, 1:29 pm	#5
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Re: Small beginners guitar amp Really nice job Joe! __________________ Colin Armstrong

16th Oct 2010, 1:54 pm	#6
fidobsa Retired Dormant Member Join Date: Mar 2009 Location: Zala, Hungary Posts: 418	Re: Small beginners guitar amp Yes, very neat work. Is it destined to go in a speaker cabinet or used as-is?

16th Oct 2010, 10:29 pm	#8
amp_mangler Retired Dormant Member Join Date: Aug 2010 Location: Mareeba, Queensland, Australia. Posts: 140	Re: Small beginners guitar amp Yeah, around 12 watts ( I didnt bother measuring it). It goes in a speaker box, a single 12" Alnico from the 60,s ( Akai) seems quite efficient ( d#mn LOUD in other words) there is one modification I made !!, the volume control has been moved to the triode grid, to allow some overdrive without the 12 watts Joe

18th Oct 2010, 4:32 am	#9
jesusjones Retired Dormant Member Join Date: Oct 2010 Location: Winnipeg, Manitoba, Canada. Posts: 1	Re: Small beginners guitar amp Very nice clean layout you have there. I wish my projects looked that sturdy and organized Cheers, Andrew P.S. Wish I knew how to wind my own transformers

18th Oct 2010, 9:52 am	#11
Aerodyne Octode Join Date: Jun 2004 Location: Hampton Vale, Peterborough, UK. Posts: 1,698	Re: Small beginners guitar amp Craftsmanship of a high order, Joe. You are, I'm sure, justly proud of your quality work. -Tony

18th Oct 2010, 11:13 am	#12
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: Small beginners guitar amp Very attractively built ! An amp constructed like that can only sound good,it wouldn't dare otherwise. If I had been the designer I would have considered specifiying 6V6's in the original design if the amp was going to get a good hammering. 6BW6's are the same thing of course, but in a B9A envelope. This means they're not so good at dissipating heat and tend to have a short(but fullfilled)life. 12 watts will certainly rattle the windows! __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

18th Oct 2010, 12:39 pm	#13
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,087	Re: Small beginners guitar amp True - but if the chassis is run out in the open, there'll be plenty of cooling. It's mainly miniature valves in close-packed miniature equipment that suffers. (Although yes, I'd have used 6V6's myself, too). I have been running a pair of 6AQ5's (B7G version of the 6V6 - talk about fitting a gallon into a pint pot), for 24 years now. I used these because (1) I have some, ex-equipment; and (2) the chassis I was using wasn't big enough for octal valveholders. But these also are running out in the open, and are surviving well!

19th Oct 2010, 9:22 pm	#14
Hybrid tellies Nonode Join Date: Jan 2004 Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area. Posts: 2,967	Re: Small beginners guitar amp What a nice tidy little job looks so profesional. Bet it can still give a lot of todays smaller guitar amps a run for their money. __________________ Simon BVWS member

23rd Oct 2010, 8:46 pm	#15
chroma04 Pentode Join Date: Jul 2008 Location: Doncaster, South Yorkshire, UK. Posts: 116	Re: Small beginners guitar amp Cracking job! Want one!! __________________ Chroma 04