Metropoulos Forum

Ok Rockstah! Hands down you have the best sounding 12xxxx series amp. Period!

Please go to http://www.putfile.com/vkaxeman/images/161354 for pics of my Marshall 1959 HW. I want to make this sound like your infamous 68 - 12xxx series amps. They sound killer in IMO. What do I need to change?
I am a beggining amp moder / future builder. Please keep it simple so I can understand. I will get some mp3's up soon.
Thanks for the help!

welcome man! and thanks for that. you will see there are many here that have a grip on the 12 series tone and have posted some killer clips.
there are some different ideas on how to achieve evh.
from my experience ill give you good starting point.

check list to evh:

330u/820 - .68u/820 split cathode
.0022u bright channel coupling cap
330u/820 v2a
33k/500p tone stack - 500p on the bright channel mix resistor
.1u in the phase inverter ( output coupling caps)
47k feedback resistor on the speaker tap ( 16 ohm feedback )

dual 16u preamp
32u PI cap
16u screens
50u mains

with everything on ten this is a real good start in evoking the dutch treat

Mark

Aaaaaaaaaa.........dutch treat.............

... which is better than a dutch overn.

Are we eatin ice creams or buidin amps! LOL,

Maybe we can build an amp that dispenses ice cream, man!!!

vkaxeman wrote:Ok Rockstah! Hands down you have the best sounding 12xxxx series amp. Period!

Please go to http://www.vk4rock.com/1959HW.htm for pics of my Marshall 1959 HW. I want to make this sound like your infamous 68 - 12xxx series amps. They sound killer in IMO. What do I need to change?
I am a beggining amp moder / future builder. Please keep it simple so I can understand. I will get some mp3's up soon.
Thanks for the help!

is that a brand spanking new HW marsh? if so they done a good job of copying Georges Stuff

I do not know why I should sound surprised but I think it looks really neat and tidy.

They have done a good job on replicating a 69 superlead at least cosmetically. I imagine the nitty gritty depends on how good the transformers/caps are. I read the sticky thread of George redoing one at the top of the page.

How much of this is due to the one ABOVE BEING DUD.

It is a shame they did not use the best components in such a boutique type product.

neikeel wrote:It is a shame they did not use the best components in such a boutique type product.

agreed!!! here in Australia these things are worth like $5k id expect all the components to be made of GOLD... im glad i found metropoulos amplifaction

is that a brand spanking new HW marsh?

This is a recently purchased Used 2005 model.

Here are MP3's of this Stock as purchased: http://www.soundclick.com/1959hwstock


Ok Rockstah, please break it down for me:

330u/820 - .68u/820 split cathode
.0022u bright channel coupling cap
330u/820 v2a
33k/500p tone stack - 500p on the bright channel mix resistor
.1u in the phase inverter ( output coupling caps)
47k feedback resistor on the speaker tap ( 16 ohm feedback )

dual 16u preamp
32u PI cap
16u screens
50u mains

Any Brand preferences for these items?
For 12xxxx do I also need an OT and choke swap?
Do you have some diagrams or pics that show where these items are located that I need to swap or can you mark up my pics? Again I am a major newbie. I understand V1 and V2 but need some clarification on a and b. Is this the 2 different sections of the preamp tube? How do you know which pins get you into the different sections? Is screens a certain pin number on output tubes?, 330u/820 does this mean capacitor value/resistor value, etc?

Thanks!

Read this thread:

http://forum.metroamp.com/viewtopic.php ... highlight=

Read this thread:

http://forum.metroamp.com/viewtopic.php ... highlight=
_________________
MacG.

Thanks for the suggestion. I have read that post before. Good stuff there! George Greatly improved the sound of that HW amp. However, it is not the tone I am looking for. I am looking for the tone that Rockstah get's with his 12xxxx series builds.

as far as the main board part of the circuit i would only make the few illustrated changes and leave the rest of it as is. ( keep on the back burner to get some mustard caps in it... but not yet.)



the parts needed are:
330u - http://store.metroamp.com/product_info. ... cts_id=289
.1u - http://store.metroamp.com/product_info. ... cts_id=370


so make these changes and see what you think about the amp.
next is the filtering.
after that is tubes.

see what happens with these factors and then begin to think about new trannys in the amp.

this would be my approach having the particular amp u have.

some food for thought

note: if u have never worked on an amp u should first understand how to drain the amp of deadly electricity if you dont already know how before u go poking around in it.

Mark

Excellent! Thanks for the follow up post with the detail Mark! Greatly Appreciated! I will try what you suggested first.

In an effort to better understand what I am looking at I made some notations on 1 of my pictures. Please let me know what I have right and what is wrong. Thanks again!

Picture edited and revised 5/11/07.

the parts needed are:
330u - http://store.metroamp.com/product_info. ... cts_id=289
.1u - http://store.metroamp.com/product_info. ... cts_id=370

Parts Ordered from George!

As soon as possible, I will get an mp3 made of the amp as it is right now and then after I add in the 2 parts you recommended.

RE:

note: if u have never worked on an amp u should first understand how to drain the amp of deadly electricity if you dont already know how before u go poking around in it.

I understand the wire with alligator clips idea (one clip on chassis and one clip on pin 1 of V1) but do I need to put a resistor in between the 2 clips? Also, should the amp Standby switch be off or on while draining? And should the amp be unplugged from the 110 outlet or left plugged into a grounded 110 outlet while switched off and draining?

Thanks again for your time and help!