Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Misc Schematics and Layouts => Topic started by: tubenit on November 02, 2008, 08:26:50 pm

Title: PRR Third watt amp
Post by: tubenit on November 02, 2008, 08:26:50 pm: I think Blind Lemon built a version of this and likes it. Don't know whether this is the schematic he ultimately used or not. I wanted to try to get it saved for the forum members.

Here is a layout that I found that is "supposed" to match this. Check for errors and comparison.

The original thread was maybe 10/07 and is gone. I found another thread that talked about using:

120:120 Isolation transformer for the PT
Hammond 262E6
P-T442 (from Antique Electronics Supply)
Fender replace reverb trannie used for the OT

With respect, Tubenit
Title: Re: PRR Third watt amp
Post by: rumble on May 06, 2009, 12:25:19 pm: hello
i found this site searching for a diy guitar tube amp with a small output in watt 's
i hope this is the correct topic to interact about this amp
it would be my first build, and would need some extra info about the isolation transformer because our power supply is 240 AC.
do i understand i correct i need a 240:120 isolation transformer?

and the other device is the p-t442
are there alternatives for this device?

watt kind of speaker would be needed in Ohms?
Title: Re: PRR Third watt amp
Post by: blackcorvo on November 30, 2009, 05:07:18 pm: Quote from: rumble on May 06, 2009, 12:25:19 pm
it would be my first build, and would need some extra info about the isolation transformer because our power supply is 240 AC.
do i understand i correct i need a 240:120 isolation transformer?

yes, you got it right.

Quote from: rumble on May 06, 2009, 12:25:19 pm
watt kind of speaker would be needed in Ohms?

it will depend on the output transformer you will use, if you don't use the model pointed in the schem. but i think it's a 8ohms load for that model.

i also have some question about this schem:

- i'd like a lil more of power... as close to 1w as possible. what if i increase the voltage to 230v? should i do mods in the output section?

- also, i only have one 6 au6, but i have a 12AX7 and wanted to use it in the pre-amp instead of the 6au6... any sugestions of pre-amp circuits? (fender, marshall, anything?)

thanks for any informations!!!
Title: Re: PRR Third watt amp
Post by: CraigB on January 21, 2010, 05:08:37 pm: Here is a layout that I plan to use to build PRR's cool little 3rd watter.

Any comments or suggestions welcome!

Regards,
Craig
Title: Re: PRR Third watt amp
Post by: DummyLoad on January 22, 2010, 06:04:29 pm: very nice layout! :smiley:

when are you going to build it?
Title: Re: PRR Third watt amp
Post by: CraigB on January 24, 2010, 10:06:57 am: Today :grin:

Regards,
Craig
Title: Re: PRR Third watt amp
Post by: 2twang2 on January 24, 2010, 01:51:23 pm: Excellent! Hope you'll post pics. I built a 12AU6 version a while back and have had a lot of fun with. It drives a 12" speaker in an open back cab.
Title: Re: PRR Third watt amp
Post by: CraigB on January 26, 2010, 04:08:45 pm: Got sidetracked on another project on Sun., but...almost done.

Regards,
Craig
Title: Re: PRR Third watt amp
Post by: CraigB on January 31, 2010, 01:41:56 pm: Layout works good, fired it up this morning. I chose to make the chassis grounding point on the input jack side of the chassis - one wire from the board buss, a wire to ground the 1M pot, and a third wire to ground the 100K pot. The input jack and 1M resistor are not wired to the ground terminal. It's nice and quiet, even through a big speaker. It is really fun to play. Thanks PRR!

Regards,
Craig
Title: Re: PRR Third watt amp
Post by: 2twang2 on February 01, 2010, 12:14:53 am: Excellent!
Title: Re: PRR Third watt amp
Post by: PRR on September 29, 2015, 08:29:51 pm: Images lost over time.

(http://i.imgur.com/oR3rf1S.gif)
Title: Re: PRR Third watt amp
Post by: isaac_teller on May 07, 2023, 10:09:40 am: Hello. What would I have to change in order to make this a headphone amp(mono of course for monitoring purposes. Thank you