Looking for advice,EL84 based Mono amp conversion/ restoration

jmilch · 12th August 2009, 01:18 AM

I recently bought a mono tube amp from a member here on the forum that turned out to be a excellent deal, in excellent condition, thanks again cscmc1!

(pics can be found here)
FS: Boulevard el84 amp

Purpose:
I would like to turn this amp into a mono guitar amplifier, and retrofit it to an older marshall head case that I have.

Boulevard 5T-17 Specs:
17 Watts
1 x EZ81 Rectifier Tube
2 x 12AX7 pre amp
2 x EL84 output tubes
4,8, and 16 ohm outputs work (screw terminal type)

The amp had been modified and simplified, but the seller wasnt exactly sure what had been done.

I also ordered the original schematic, and have found the following changes:
Volume pot was removed
Tone / Bass / Trebel / Selector switch removed
All wiring except the aux RCA style input has been removed

Is it possible to:
I would like to add a master volume control pot, and if possible a bass and trebel control, and a tone knob.

I am relatively new to the point to point wiring, and tube amplifiers, but I am very handy with a DMM and a soldering iron.

I do have the orignal schematic available, I am going to upload it this evening if it would be helpful.

Questions:
How do I go about adding a master volume knob?

How do I add a bass and or trebel control?

Where can I find a schematic for a basic tone stack ? (if thats using the correct lingo?)

Is it possible to add a seperate gain control to add a bit of distortion without cranking the volume?

Do I need to include a stanby circuit like alot of larger wattage amps have?

Can I repaint the power tranformer with regular spray paint? Its a bit rusty

As always please point me in the wrong direction if I have overlooked something simple. Please take it easy as I am new to the hobby.

aardvarkash10 · 12th August 2009, 09:34 AM

AX84

jmilch · 12th August 2009, 03:23 PM

I have scoured that particular forum and been soaking up information, I found that site a few weeks ago. I was just looking for a more personalized answer(s) from forum members. Its a bit easier to read one response from a member than it is to search multiple threads for hours.

I will check that site over again, thanks for the recommendation.

Can anyone answer any specifics for me here? Thanks again

jmilch · 12th August 2009, 03:29 PM

I have also found this particular site useful, just a reference link for anyone interested

http://www.netads.com/~meo/Guitar/Amps/PA2Guitar/

But I havent found answers to how to add the tone stack, and whhat I can use to repaint the transformer.

jmilch · 12th August 2009, 06:01 PM

Ok I've found a basic marshall tone stack called "18 watt" found here

http://amps.zugster.net/articles/tone-stacks#18Watt

So I am going to incorporate that according to the information in the link provided above about converting PA amps to guitar amps.

I think that should cover some of my questions. I am open to any feedback or ideas for this project, and I will be uploading pictures soon.

12th August 2009, 09:34 AM	#2
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	go here AX84 __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012

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12th August 2009, 01:18 AM	#1
jmilch diyAudio Member Join Date: Aug 2009	Looking for advice,EL84 based Mono amp conversion/ restoration I recently bought a mono tube amp from a member here on the forum that turned out to be a excellent deal, in excellent condition, thanks again cscmc1! (pics can be found here) FS: Boulevard el84 amp Purpose: I would like to turn this amp into a mono guitar amplifier, and retrofit it to an older marshall head case that I have. Boulevard 5T-17 Specs: 17 Watts 1 x EZ81 Rectifier Tube 2 x 12AX7 pre amp 2 x EL84 output tubes 4,8, and 16 ohm outputs work (screw terminal type) The amp had been modified and simplified, but the seller wasnt exactly sure what had been done. I also ordered the original schematic, and have found the following changes: Volume pot was removed Tone / Bass / Trebel / Selector switch removed All wiring except the aux RCA style input has been removed Is it possible to: I would like to add a master volume control pot, and if possible a bass and trebel control, and a tone knob. I am relatively new to the point to point wiring, and tube amplifiers, but I am very handy with a DMM and a soldering iron. I do have the orignal schematic available, I am going to upload it this evening if it would be helpful. Questions: How do I go about adding a master volume knob? How do I add a bass and or trebel control? Where can I find a schematic for a basic tone stack ? (if thats using the correct lingo?) Is it possible to add a seperate gain control to add a bit of distortion without cranking the volume? Do I need to include a stanby circuit like alot of larger wattage amps have? Can I repaint the power tranformer with regular spray paint? Its a bit rusty As always please point me in the wrong direction if I have overlooked something simple. Please take it easy as I am new to the hobby.

12th August 2009, 03:23 PM	#3
jmilch diyAudio Member Join Date: Aug 2009	I have scoured that particular forum and been soaking up information, I found that site a few weeks ago. I was just looking for a more personalized answer(s) from forum members. Its a bit easier to read one response from a member than it is to search multiple threads for hours. I will check that site over again, thanks for the recommendation. Can anyone answer any specifics for me here? Thanks again

12th August 2009, 03:29 PM	#4
jmilch diyAudio Member Join Date: Aug 2009	I have also found this particular site useful, just a reference link for anyone interested http://www.netads.com/~meo/Guitar/Amps/PA2Guitar/ But I havent found answers to how to add the tone stack, and whhat I can use to repaint the transformer.

12th August 2009, 06:01 PM	#5
jmilch diyAudio Member Join Date: Aug 2009	Ok I've found a basic marshall tone stack called "18 watt" found here http://amps.zugster.net/articles/tone-stacks#18Watt So I am going to incorporate that according to the information in the link provided above about converting PA amps to guitar amps. I think that should cover some of my questions. I am open to any feedback or ideas for this project, and I will be uploading pictures soon.

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