My Marshall Conversion From PCB To PTP

[Marcel]

Re: My Marshall Conversion From PCB To PTP

I'm still tweakin on the dropping resistors to get my overall voltages where I want them....

just interested - which voltages are you talking about?

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Dang John. Thats sweet looking. Is this something you did as a result of getting that amp book at the show? Or was this something you were working on before?

Very nice.

Artie

(Say "hey" to Steve for me.)

Hello buddy.....The book got me motivated to finally get around to doing this,but it was something I wanted to do about 2 years ago and never got around to it....I also have a BF Fender Deluxe Reverb Board I built and I was going to build that amp....Just have to get around to buying the transformers and a chassis for that project....Someday though..:smack:

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

just interested - which voltages are you talking about?

Private Eyes on the scene here.....LOL...

I want a bit more clean headroom....I'm reading across pins 1 and 6 at my phase inverter...I need to slightly increase those voltages..

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Now that is one neat Marshall

I'm all about clean and neat buddy! Oh.....And "TONE" LOL:chairfall

 

[kmcguitars]

Re: My Marshall Conversion From PCB To PTP

I could,but the 2 amps are different,plus the 1987 uses the 1202-164 PT and your's probably has the 1202-324 or whatever the number is?

I'm still tweakin on the dropping resistors to get my overall voltages where I want them....

I know what you mean. I'm using a New Sensor MPT 50. Just curious to see if I'm in the ballpark. I'm reading -32 on pins 5, And 461 on pins 3. Those reading seem off to me? (I'm awaiting the proper resistors from metro. They screwed me up again:smack: ) Right now I have a 27k and 2 100k's in series in place of the 220k.:13: on the standby switch input. :duh: I noticed your layout uses a 56k NFB resistor. ( Mine has a 47k ganged on the 8 ohm tap) When I get the proper resistors in place and still have a oscillation problem?
( I BETTER NOT:fingersx: ) I guess the next thing to do would be bump the NFB resistor up to 56k ? Hope I don't have to go there.:eek13:

 

[Stratman]

Re: My Marshall Conversion From PCB To PTP

I finally got around to Sozo caps

I told ya'll these Sozo caps are the bomb.

I got Scott to use them in Edana 45 (JB-007) and love them...

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

I know what you mean. I'm using a New Sensor MPT 50. Just curious to see if I'm in the ballpark. I'm reading -32 on pins 5, And 461 on pins 3. Those reading seem off to me? (I'm awaiting the proper resistors from metro. They screwed me up again:smack: ) Right now I have a 27k and 2 100k's in series in place of the 220k.:13: on the standby switch input. :duh: I noticed your layout uses a 56k NFB resistor. ( Mine has a 47k ganged on the 8 ohm tap) When I get the proper resistors in place and still have a oscillation problem?
( I BETTER NOT:fingersx: ) I guess the next thing to do would be bump the NFB resistor up to 56k ? Hope I don't have to go there.:eek13:

Actually I'm using a 100k hooked to the 4 ohm tap for my feedback,but I have a resonance(tightening)control on the other side of the feedback circuit...I'm going to try a .68 in place of the .1 across my presence pot and see what I Like better?

What resistors are you speaking about? The 220k splitters before your output tubes? I Like 100kS there...And you're using a 27k NFB Resistor?

I'm around 440 to 445 to my plates and around -41 with my tubes set for 36 millivolts across my 1 ohm cathode resistors...These voltages I guess are a sweet spot from what others tell me?

Not sure on your wall voltages,but mine were based on 122 volts this morning.

I'm using an O.E.I Plexi output transformer,but I'd like to try Trace's Custom made MM trasformers one of these days...He's really raving about it...LOL

 

[callous_frigid_chill]

Re: My Marshall Conversion From PCB To PTP

Looks pretty cool.

 

[kmcguitars]

Re: My Marshall Conversion From PCB To PTP

What resistors are you speaking about? The 220k splitters before your output tubes? I Like 100kS there...And you're using a 27k NFB Resistor?

My NFB resistor is a 47K. The resistor's i'm talking about are at the Input of the Bias circuit B4 the IN4007 diode. Metro sent me the 2203 kit.:yell: So I had a 27k where a 220k should be. So I just ran 2 100k's in series with it as a temporary fix until he sends me the 220k. So this alone is messing up my voltages. So I'm in limbo until I get the right parts. The amp is sounding pretty good, But I'm not gonna play it until I have the right parts/voltages.

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

My NFB resistor is a 47K. The resistor's i'm talking about are at the Input of the Bias circuit B4 the IN4007 diode. Metro sent me the 2203 kit.:yell: So I had a 27k where a 220k should be. So I just ran 2 100k's in series with it as a temporary fix until he sends me the 220k. So this alone is messing up my voltages. So I'm in limbo until I get the right parts. The amp is sounding pretty good, But I'm not gonna play it until I have the right parts/voltages.

Oh ok....I have a 150k there....Stock value is the 220k...I'm using the 3 watt diodes that I got from Hoffman ....Alot of guys are raving about the "FRED" Diodes....Haven't tryed them? You should also have a bias set resistor of 47k,sometimes 56k(Depending on 6550 or EL34s)and the 15K...

THE 100k NFB resistor to the 4 ohm tap is the stock values on my 73 50 watter and offers less n feedback and a bit more gain compared to going to the 8 ohm tap or lowering the 100k to 47k on the 4 ohm tap...Marshall dropped the .68 cap across the 820 resistor on this year and that's probably the reason for the 100k/4 ohm NFB tap...

My switch that I have connected to V2 has the .68 and other higher values,or I can choose to leave the cap out....I like the cap out the best though..The sound is more open and less gainey for clean stuff....

 

[shredaholic]

Re: My Marshall Conversion From PCB To PTP

Selectable switch on V2s cathodes to dial in different cap values,or no cap across the 820 resistor

That's my favourite mod in my amp, it worked great until the switch accidentally broke while pulling the amp out of the chassis :smack:

I like selecting the classic Marshall bypass caps, ie. .68, 330uf and none.

I don't like the .1 caps in my lead amps....My 4x12 V30 cab doesn't need the .1 caps either! LOL....The resonance control and the V2 cathode cap switch takes care of that...You want to get your lows early in the amp,so you don't get too muddy at the output stages...You already knew this though...

The .022 caps are more great..

I've read that about running the cd player through the amp....Pretty good idea also!

I also stick with the 500 pf/.022/.022 tone stack but I use a pot to vary the resistance..I Like 47k alot over 33k...

I also increase the .022 cap to the mid pot to a .033. and it's a slight change from the values I mention above.

Haha yeh - I like it muddy in the output stage, that's why I do it! I'm using them with a 100pf fizzy cap, and last night I took out 1 section of each of the dual 50uF screens caps so I'm left with two 50's in series (25uF), I'm loving the sound of my output section now. It's definately not tight enough for a typical lead sound, but it's my perfect tone for combined lead and rhythm. Think 'Fair Warning' by Van Halen.

I'm planning on having some sort of tone stack changing switch too, I'm currently on 56k/250pf and will have a switch to select between that and the 33k/500pf tone stack. A variable pot for it is a nice idea though, I'd like to try that too at some point.

How do you find the .033 cap sounds compared to the .022 for the mid pot?

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Got the second set of .022 Sozo caps for my Marshall and I tweaked the bright caps for both channel volumes....After some tubes,I'm done with it....Sounds just amazing!

 

[Lewguitar]

Re: My Marshall Conversion From PCB To PTP

Boy John...that's so neat looking it now looks like a HiWatt inside! :smack: Super nice work!

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Boy John...that's so neat looking it now looks like a HiWatt inside! :smack: Super nice work!

Thanks Lew.....Nothing and I mean nothing,matches a Hiwatt on the inside...:13: First time I ever saw the insides of a Hiwatt,I almost wet myself...... ;o)

I tryed to keep the wires short and neat to keep oscillation,noise,and buzzing out and the amp is amazingly quiet....Sounds great....Better than it did...Thankfully! :fingersx:

I Like the Sozo caps alot and I guess they're "supposed" to be a Phillips/Mustard cap clone? They're sweet and clear sounding,but they'll need to be broken in from what it says on the Sozo sight....Trace worked with me on getting my voltages and component location etc...right....Came out great and it was alot of fun also...

Coming from you Lew,I always appreciate your comments....Thank You!

 

[Vasshu the humanoid typhoon]

Re: My Marshall Conversion From PCB To PTP

And we name thee John Reeves!!
Mr Clean and Neat, and that is no shame for sure!
Man I love that amps inside
I love neat amps a great deal.
Have you tried the Plexitone through it??

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

And we name thee John Reeves!!
Mr Clean and Neat, and that is no shame for sure!
Man I love that amps inside
I love neat amps a great deal.
Have you tried the Plexitone through it??

Not yet RID,but man I know how great it's gonna sound through my amp!

 

[tone4days]

Re: My Marshall Conversion From PCB To PTP

congrats john - real nice work

i read an interesting article this week (in musicains hotline, i think) about carbon comps that said the 2nd order harmonics dont kick in appreciably unless you are hitting them with sizeable voltages ... i am guessing your ears are the final arbiter that shows you are doing just fine with the metal films

enjoy that renewed marshall

cheers
t4d

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

congrats john - real nice work

i read an interesting article this week (in musicains hotline, i think) about carbon comps that said the 2nd order harmonics dont kick in appreciably unless you are hitting them with sizeable voltages ... i am guessing your ears are the final arbiter that shows you are doing just fine with the metal films

enjoy that renewed marshall

cheers
t4d

Carbon comps have their own gain that they introduce into a circuit when pushed to their limits.....But...CC resistors are noisy,create hiss,and popping noises on the plate resistors of preamp tubes....If you've ever owned a BF Fender that had some bad 100k CC resistors,you'd hear all of these things mentioned out of 1 amp....I like MF resistors because I Know that the values will be the same in 10 years,as they are today...CC resistors are normally way out of spec and read high...I was reading some old CC resistors that I Pulled out of a 65 Deluxe Reverb amp...I saw 220k resistors that read almost 300k....100k resistors that read 119k etc....This is the reason for alot of inconsistencies we hear between like amps.....The metal films are fine...My amp isn't at all harsh and it's stable and very quiet also...I do use Carbon Film resistors in some spots,but only because I can't get a certain MF value in a 1 watt resistor....You'll notice I used 1 watt CF resistors as my splitter resistors to the output tubes....You just won't see any CC stuff in my amp....Alot of fallacy stuff and I don't buy into it.....CC resistors were cheap and plentiful and that's why they were used ;o)

 

[Jeff Seal]

Re: My Marshall Conversion From PCB To PTP

Nice looking job!!!!!

Jeff Seal

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Nice looking job!!!!!

Jeff Seal

Thanks Jeff.....Coming from you Jeff,I take this as a nice compliment....