GU50 Prototypes

matejsirk · 2nd January 2012, 07:41 PM

Some time ago, me and friends decided that we make a few prototypes with GU50. The idea was to test as many different combinations. For input tube we decided for 6SN7, 6SL7, 6N1P, 6N23P, 6N6P, D3a, 6C3P, ECC83, ECC85, ECC81.

We made some SE prototypes, one of the PSE and the PP one. As the input tube we test: D3a, 6C3P (the best two), 6N23P, 6SN7, 6N6P (also very good - not enough gain), ECC83, ECC85 (not so good). The project is continuing. Now I'm working on the development of housing.

We found that the GU50 is one of the best, for me better than EL34 or EL84.

A couple more pictures of prototypes:

fabioab · 8th November 2012, 12:25 AM

Hi, my prototype is a mix of Fender AB763 with 12Ax7 as phase inverter, and two Gu50 at the power.

ry50 - 80W - YouTube
Only volume pot.

Almost finished!

Wavebourn · 01:00 AM

Quote:

Originally Posted by matejsirk

We found that the GU50 is one of the best, for me better than EL34 or EL84.

Me too.

Also I found that it is better than that 6L6 clones like KT-88.

Here are my prototypes:

Junm · 8th November 2012, 05:05 AM

nice work sir wave,

I'm also planning to do a PP gu50 with 6n6p drivers or 6n1p....any schematics suggestion for a 50w amp?

Jaap · 8th November 2012, 07:45 AM

Quote:

Originally Posted by matejsirk

Some time ago, me and friends decided that we make a few prototypes with GU50. The idea was to test as many different combinations. For input tube we decided for 6SN7, 6SL7, 6N1P, 6N23P, 6N6P, D3a, 6C3P, ECC83, ECC85, ECC81.

We made some SE prototypes, one of the PSE and the PP one. As the input tube we test: D3a, 6C3P (the best two), 6N23P, 6SN7, 6N6P (also very good - not enough gain), ECC83, ECC85 (not so good). The project is continuing. Now I'm working on the development of housing.

We found that the GU50 is one of the best, for me better than EL34 or EL84.

A couple more pictures of prototypes:

Schematics ?

fabioab · 11:28 PM

Hi, I would state some "strange" behavior of my ampli.
When I cranck (or close cranck) the volume pot, it starts a riiiiiiizzzzzzz. Obvioulsly the amplifier is totally saturated and crunched. It happens without the guitar plugged too.

Some Ideas what could cause this effect. The circuit was based in the Fender 6G8 circuit end AB763. The PI tube is a 7025 as in 6G8.

Thanks a lot who try give-me an explanation!
I'm sending some pictures.
FAB

fabioab · 19th November 2012, 10:12 PM

nobody has some idea ???

Wavebourn · 19th November 2012, 10:31 PM

I have an idea. It is probably the result of some parasitic feedback, either capacitive between close input and output wires, or some common wire (so called ground) is soldered in the wrong place.

fabioab · 19th November 2012, 10:40 PM

Thanks Wavebourn, some day I will try fix the problem! But I would like to have some idea about what could cause the problem.
For the time being, I'm playing to have some fun!
Cheers FAB

Alphy · 28th November 2012, 07:32 PM

Hi Wavebourn, as I pm'd you months ago, still waiting for your 30+ Watts design with this endvalve

.

19th November 2012, 10:31 PM	#8
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	I have an idea. It is probably the result of some parasitic feedback, either capacitive between close input and output wires, or some common wire (so called ground) is soldered in the wrong place. __________________ If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
3-Way Active Prototypes	classdpwr	Multi-Way	0	13th November 2011 06:18 PM
Heil AMT Prototypes? Anyone ever seen anything like these units?	matt28sr	Planars & Exotics	15	20th September 2009 07:06 AM
Prototypes...	MikeB	Solid State	23	20th December 2004 09:52 AM
FE107e prototypes done! 10" XLS next	Dave Jones	Full Range	8	26th May 2004 11:38 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

8th November 2012, 12:25 AM	#2
fabioab diyAudio Member Join Date: Apr 2010	Hi, my prototype is a mix of Fender AB763 with 12Ax7 as phase inverter, and two Gu50 at the power. ry50 - 80W - YouTube Only volume pot. Almost finished!

8th November 2012, 05:05 AM	#4
Junm diyAudio Member Join Date: Dec 2008 Location: Mabalacat, Pampanga	nice work sir wave, I'm also planning to do a PP gu50 with 6n6p drivers or 6n1p....any schematics suggestion for a 50w amp?

19th November 2012, 10:12 PM	#7
fabioab diyAudio Member Join Date: Apr 2010	nobody has some idea ???

19th November 2012, 10:40 PM	#9
fabioab diyAudio Member Join Date: Apr 2010	Thanks Wavebourn, some day I will try fix the problem! But I would like to have some idea about what could cause the problem. For the time being, I'm playing to have some fun! Cheers FAB

28th November 2012, 07:32 PM	#10
Alphy diyAudio Member Join Date: Mar 2012	Hi Wavebourn, as I pm'd you months ago, still waiting for your 30+ Watts design with this endvalve .