1987/1959 VS 2204/2203 Preamp

NewReligion · 11-27-2011, 05:12 PM

Hi guys. I have a novice understanding of Amplification electronics compared to most of you. I can change tubes and bias correctly after using a meter to read the plate voltage and have done a few mods on a 2203X that I owned.

There have been a few members that have aided me with knowledge and information. Many of those people are busy elsewhere lately. (Thanks guys)

My question/interest is as follows.
Can you help me understand the difference between Cascaded (2203) and non Cascaded (1987X) gain stages. In particular how V1A/B and V2A/B differ from each other in the two models. I have been studying the preamp schematics of the 2203/2203X vs the 1987X (2007 model). I believe that the circuits are very similar but I am confused when it comes to the Cathode Resistors and Plate Resistors.

For example:

I (Think I know) that changing the cathode resistor of a 2203's V1A from 2k7 to a 1k will give a small amount of gain increase.

This is a lot for one post so I will wind it down.

I believe that only V1A/B and V2A are the gain stages for the 2203/X which is a total of 3 stages.

What are the fuctions of V2B in both models.

Thanks in advance from one who wants to know.

New Religion

NewReligion · 11-27-2011, 06:53 PM

Guess I will buy a couple books and research other sources.

Just spent the last 3 hours reading and now better understand cascade vs non. In addition I have found that there are a few different schematics when it comes to the 1994-2002 50 watt Plexi RI model 1987X/XL. I have found that the later models are wired differently @ V2.

Any additional information or tips are welcome.

Thanks.

Joey Voltage · 11-27-2011, 08:43 PM

Quote:

Originally Posted by NewReligion

Guess I will buy a couple books and research other sources.

Damn! Giving up only after a few hours? V2 has the same function in both models it's v1 that differs.

plexifier · 11-27-2011, 08:59 PM

The main differences between a 2203 and 1959 are V1 and the volume pots. From V2a on, they are basically the same.

1959 uses V1a for the normal channel and V1b for the bright channel. 2203 cascades V1a into V1b.

Here are the simplified signal paths:

1959 bright channel:
input > V1b > volume pot > mixer resistors > V2a > V2b > tone stack > PI...

2203:
input > V1a > preamp pot > V1b > voltage divider > V2a > V2b > tone stack > master volume > PI...

V2b is a cathode follower that drives the tone stack in both. As you can see, a 1959 has 2 gain stages before the cathode follower, where a 2203 has 3.

The mixer in a 1959 combines the two channels before going to V2. The voltage divider in a 2203 is in the same place and behaves similar to the bright channel mixer resistor in a 1959 (attenuates the signal and boosts high frequencies due to the bypass cap).

Hope this helps.

NewReligion · 11-27-2011, 09:17 PM

Quote:

Originally Posted by Joey Voltage

Damn! Giving up only after a few hours? V2 has the same function in both models it's v1 that differs.

Hey Brother Joey, great to hear from you. Not that I was trying to coax you out, lol. I have all of my notes JV. I am trying to apply what I think I know with fresh logic to a 2007 50watt RI 1987XL.

And thank you Plexifier.

NewReligion · 11-27-2011, 09:20 PM

As stated earlier I think I found the correct Schem for this 2007 model 1987XL. I still need to compare it but the schem shows the Cathode resistors for V1A, V1B and V2A all to be 820 and V2B @ 100K Kind of ODD I thought.

NewReligion · 11-27-2011, 09:23 PM

So the voltage divider on the 2203 allows for the cascade. What function does the mixer resistor carry out on the 1959/1987?

Also, If I decided I wanted just a bit more hair/gain I could lower the value of V1B cathode resistor?

I'm a NewbTard.

Joey Voltage · 11-27-2011, 09:40 PM

Quote:

Originally Posted by NewReligion

Hey Brother Joey, great to hear from you. Not that I was trying to coax you out, lol. I have all of my notes JV. I am trying to apply what I think I know with fresh logic to a 2007 50watt RI 1987XL.

And thank you Plexifier.

Oh Dave I was just teasing you, I actually started writing a better post (more useful) about it afterwards and my phone kicked it to the curb .

I need a sec to recoup

NewReligion · 11-27-2011, 09:48 PM

New England Amp Tech and Builder? Sounds Great, congratulations Joey.

My interest here is to simply add just a little saturated gain without killing the amp.

I had the 2203X sounding better than ever but just was not my cup of tea.

plexifier · 11-27-2011, 11:05 PM

Quote:

Originally Posted by NewReligion

So the voltage divider on the 2203 allows for the cascade.

No. It's after the cascade. It just attenuates low/mid frequencies before V2 so you don't end up with way too much gain (mush).

Quote:

Originally Posted by NewReligion

What function does the mixer resistor carry out on the 1959/1987?

It mixes the two channels together and there is a bypass cap on the bright channel that makes it brighter and also allows highs from the normal channel to go to ground, which makes that channel darker.

Quote:

Originally Posted by NewReligion

Also, If I decided I wanted just a bit more hair/gain I could lower the value of V1B cathode resistor?

Not really. You'll only add a tiny bit of bass and low-mid gain by reducing that resistor because the 0.68uF bypass cap is already boosting gain there a lot.

One place you can add gain is a V2a cathode bypass cap. I don't think any of the 1987 RI's have that cap. Adding a 0.68uF parallel to the V2a cathode resistor will boost mids and highs. Use a larger cap like 10uF to boost all frequencies.

Either will add a lot of gain but it changes the tone too. It sounds thicker, sometimes too thick. Personally, I don't like a bypass cap there but I mainly go for AC/DC type sounds. It's better for Van Halen or other higher gain stuff.

NewReligion · 11-28-2011, 05:24 AM

Quote:

Originally Posted by plexifier

No. It's after the cascade. It just attenuates low/mid frequencies before V2 so you don't end up with way too much gain (mush).

It mixes the two channels together and there is a bypass cap on the bright channel that makes it brighter and also allows highs from the normal channel to go to ground, which makes that channel darker.

Not really. You'll only add a tiny bit of bass and low-mid gain by reducing that resistor because the 0.68uF bypass cap is already boosting gain there a lot.

One place you can add gain is a V2a cathode bypass cap. I don't think any of the 1987 RI's have that cap. Adding a 0.68uF parallel to the V2a cathode resistor will boost mids and highs. Use a larger cap like 10uF to boost all frequencies.

Either will add a lot of gain but it changes the tone too. It sounds thicker, sometimes too thick. Personally, I don't like a bypass cap there but I mainly go for AC/DC type sounds. It's better for Van Halen or other higher gain stuff.

Thank you Plexifier.

Joey Voltage · 11-28-2011, 04:56 PM

Quote:

Originally Posted by NewReligion

New England Amp Tech and Builder? Sounds Great, congratulations Joey.

well I wouldn't say it really deserves accolades as I have been doing for a good chunk of my income for quite a few years now, just never really advertised it so much, just a little shameless self promotion I guess.

Quote:

Originally Posted by NewReligion

My interest here is to simply add just a little saturated gain without killing the amp.

I had the 2203X sounding better than ever but just was not my cup of tea.

well there's many way and places to do that in this circuit despite what many people think, and it is very possible to get super saturated gain structure out of that amp (as much as some 4 stage designs) with just the three cascaded stages that are in it, although at the expense of some tone shaping capability. it's not necessarily the amount of voltage gain that creates musical gain, than more the combination of frequency shaping, and clipping thresholds.

The problem is that you asked a monster of a question. Plexifier gave you the general run down, but it can get to be a little more involved, especially when speaking about the musical aspect. so I'm going to answer about the specific example you asked about because I find it easier to give you a little more concise of an answer just focusing on single questions, rather than write for hours and still be be vague.

Now generally there are a few major parameters (and many other ones that also some of which have tonal implications) that control the DC, and AC voltage gain of the typical 12ax7 common cathode preamp gain stage in the typical guitar amp- the fundamental four being the plate resistor, the cathode resistor, the AC load, and whether or not the cathode is bypassed. the latter three have more affect in the AC realm which to make a blanket statement is more important as far as gain is concerned. of the fundamental ones, you asked about changing v1b's cathode resistor to 1K versus the 2.7K that is stock (where does that sound familiar?) ignoring the .68uf cap, Doing this not only has an effect on both the DC operation of the valve, and AC gain of the stage, but also on the sound/harmonic structure.

Now just forgetting we have resistor bypassed, It changes the DC operation by biasing the stage more asymmetric towards the warmer end of the spectrum which in turn has an effect on the clipping threshold (not so much on the first stage though). comparatively 1K also increases the "real" gain (AC gain) by reducing degenerative feedback, which is an unavoidable byproduct of using resistive cathode biasing.

When you start throwing cathode bypass in this mix it gets a little more complex and interesting, as bypassing this resistor now maximizes the gain, or makes it closer to it's theoretical DC calculation by making it look to AC as if it's not there for a broad range of frequencies, or a select range, but sticking with the 1K example on v1b, and assuming you kept the .68uf, the frequency of the shelving filter this creates shifts up, and both the slope, and strength of the filter changes. with the stock .68uf/2.7K you have a shelving filter that starts working at around 80hz or so , and peaks at around 1Khz@ 8db really emphasizing mids and treble. with the 1K .68uf combo the start frequency moves up to 230hz, and then peaks at around 2.2K or so, but with only a strength of about 3-4db, so it gives more emphasis on high mids and treble, but is a perceived much weaker filter because it isn't working against as much initial degenerative feedback.

I hope this helps a little, and this is just a surface scratcher, if you wanted more in depth anything just ask, and I'll do my best to help.

Joey Voltage · 11-28-2011, 05:19 PM

Quote:

Originally Posted by plexifier

Not really. You'll only add a tiny bit of bass and low-mid gain by reducing that resistor because the 0.68uF bypass cap is already boosting gain there a lot.

I don't know if I would agree that you increase bass, and mids more per se, than saying you will just have a less drastic of a treble shelving (and at a different frequency) with the 1K/.68u. Although I guess it all depends on what you plan to pass through too. however the 1K will sound different because of the shift in bias point.....to me it sounds a bit hairier.

NewReligion · 11-28-2011, 05:48 PM

Outstanding Sir!

JV, thank you for taking the time to explain some of the major parameters in addition to the importance of frequency shaping, and clipping thresholds.

Much to think about and organize into my notes. Sometimes intellectual property is priceless.

Now I need to figure out which Schematic applies to this head as I found a few which differ. That can toy with a newb like me.

David

Lane Sparber · 11-28-2011, 06:42 PM

Also remember, David, that while changing one gain stages' topology can alter the tone shaping of that particular stage, it's best to understand the amp as a whole and absorb it all (e.g. how each stage is designed to function and shape the sound of the amplifier) before changing anything. For example, the SECOND stage in a classic 2203/2204 preamp is biased coldly - ICE coldly with just a single, unbypassed 10k resistor. This takes the "warmer" signal and then sends it clipping into the OPPOSITE cooler end of the spectrum. As a matter of fact, IMHO this stage having its' bias point at such an extreme is part of the reason most say that this amp doesn't "clean up" well. After this stage, the signal goes through one last "warmer" gain stage biased by an unbypassed 1k resistor. So, just in terms of the various stages' bias points we can see an intricate warm-cold-warm thing happening, and understanding how these stages work TOGETHER gives us a much more informed opinion in terms of deciding how to mod an amp for tone, or else you're spending forever blindly swapping components until you "luck" into a sound you like!

Hope this helps, and I'm sure Joey will nail me if I've mis-represented anything!

-Lane

NewReligion · 11-28-2011, 08:37 PM

Hi Lane. Great to see that you have stopped by as well. Great advice to consider the entire preamp section when targetting a desired result from modification(s).

I do understand that less clipping/voltage drop/EQ changes in small quantities in different areas is much more pleasing to the ear than one huge alteration.

Is the warm/cold/warm approach relative to the asymmetrical vs symmetrical clipping diode lesson we discussed earlier this year?

Lane Sparber · 11-28-2011, 08:46 PM

Not really. That was a whole separate issue.

Tube clipping is almost always asymmetrical in nature.

-Lane

axemane · 11-28-2011, 09:11 PM

Wow

this is a killer thread.

I have learned a lot but yet still don't understand quite all of it....

Joey Voltage , you should write a book sir......You are always most helpful and your knowledge is endless it seems.

axemane · 11-28-2011, 09:43 PM

??? where did my post go?

check...test...

TradAmpGuy · 11-28-2011, 11:17 PM

Would I be off base to mention that part of the warm/cold thing is that a tube that clips at saturation sounds different than one clipping at cut off?

ramhi4x · 07-07-2012, 09:55 AM

So is a 2204/2203 just a 1987/1959 with an MV and a one wire mod so to speak please?

hbach · 07-07-2012, 02:54 PM

Hey ramihi,
They are very similar but one big difference would be the very cold biased second stage on the 2203/4. This stage will be the one providing most the preamp overdrive and will sound different that the two normally parallel warm stages of the 1987/1959 cascaded.

Bit of an old thread, but a gem indeed!

NewReligion · 07-07-2012, 03:40 PM

Quote:

Originally Posted by hbach

Hey ramihi,
They are very similar but one big difference would be the very cold biased second stage on the 2203/4. This stage will be the one providing most the preamp overdrive and will sound different that the two normally parallel warm stages of the 1987/1959 cascaded.

Bit of an old thread, but a gem indeed!

The support from the gentlemen on this thread was amazing. They continue to support me with my education.

Thanks to all. True professionals.

David Hopkins.

Les Moore · 07-07-2012, 06:01 PM

Jusr love to read these kind of threads! Not at all getting it all, but bit by bit, maybe one day... Maybe.

hbach · 07-07-2012, 10:14 PM

Quote:

Originally Posted by Les Moore

Jusr love to read these kind of threads! Not at all getting it all, but bit by bit, maybe one day... Maybe.

Read the chapter on the common triode gain stage from Valve Wizard. Excelent stuff.

Les Moore · 07-08-2012, 07:08 PM

Done that. About ten times

Every time I get a little closer to understanding but I don´t think I ever will get to the level of you guys. I think that to be able to grasp the concept of the entire chain, like Lane was talking about, you should have a good understanding of electronics, how components work, how they interact and how a minute change in A has an effect on G. I´ve been trying to understand how caps work, how tubes work and so on, but I can´t seem to wrap my brain around the signal chain as a whole. But it´s so fascinating that I will never tire reading this stuff

hbach · 07-08-2012, 09:24 PM

Hey Les, I know what you mean. As a hobbyist I also try to take in as much as I can. But end of the day what I need the most of, and don't have, is listening experience. Just having tried out how things sound and interact is the key. Once you have say a gain stage and a tone stack the interaction and the math is staggering (just remember the current in a cap is 90° of phase with the voltage or complex if you rather use that) and sims work nice for most things but a sim won't tell you how a guitar actually will sound through that amp.

Les Moore · 07-08-2012, 10:08 PM

Exactly. Forgot to say that. Experience! What does it mean soundwise to change the value of a cap or a resistor in this or that place? Film, carbon, mica? The variables seem to be endless. That´s the fun. The core of soundchasing

dreyn77 · 07-15-2012, 02:22 AM

If you want to experiment open the control compartment in you GUITAR and change the capacitor going to the tone pot, change the pot value (the pot is a resistor) It's the SAME effect in the amp! and the pedals! also amplifiers. VERY boring simple stuff! they talk with 'hot' and 'cold' words so it sound more interesting than it is! HOT means HIGH CURRENT (high resistance) cold means LOW CURRENT (low resistance) An 800 will never sound like a Plexi, the current in an 800 has been CUT in HALF!!!!!!! a DSL has been CUT in HALF again, -75% (scaled down versions of the 'BIG BOY' Plexi) MY little 'park' transistor has the full Van Halen first album tone/ saturation etc... (every song) at a fraction of the ear damaging volume! Fully scaled down exact copy of the original. just run the park amp into a 'real' speaker and a plywood speaker box! No NEED to 'MOD' the amp by some 'tossa' who just RIPS YOU OFF! and TALKS SHIT to you while he's RIPPING YOUR MONEY from your POCKET!!!!!!!!

11-27-2011, 05:12 PM	#1 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	1987/1959 VS 2204/2203 Preamp Hi guys. I have a novice understanding of Amplification electronics compared to most of you. I can change tubes and bias correctly after using a meter to read the plate voltage and have done a few mods on a 2203X that I owned. There have been a few members that have aided me with knowledge and information. Many of those people are busy elsewhere lately. (Thanks guys) My question/interest is as follows. Can you help me understand the difference between Cascaded (2203) and non Cascaded (1987X) gain stages. In particular how V1A/B and V2A/B differ from each other in the two models. I have been studying the preamp schematics of the 2203/2203X vs the 1987X (2007 model). I believe that the circuits are very similar but I am confused when it comes to the Cathode Resistors and Plate Resistors. For example: I (Think I know) that changing the cathode resistor of a 2203's V1A from 2k7 to a 1k will give a small amount of gain increase. This is a lot for one post so I will wind it down. I believe that only V1A/B and V2A are the gain stages for the 2203/X which is a total of 3 stages. What are the fuctions of V2B in both models. Thanks in advance from one who wants to know. New Religion Last edited by NewReligion; 11-27-2011 at 05:53 PM.

11-27-2011, 06:53 PM	#2 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	Re: 1987/1959 VS 2204/2203 Preamp Guess I will buy a couple books and research other sources. Just spent the last 3 hours reading and now better understand cascade vs non. In addition I have found that there are a few different schematics when it comes to the 1994-2002 50 watt Plexi RI model 1987X/XL. I have found that the later models are wired differently @ V2. Any additional information or tips are welcome. Thanks. Last edited by NewReligion; 11-27-2011 at 08:40 PM.

11-27-2011, 08:59 PM	#4 (permalink)
plexifier Senior Member Join Date: Aug 2011 Posts: 474	Re: 1987/1959 VS 2204/2203 Preamp The main differences between a 2203 and 1959 are V1 and the volume pots. From V2a on, they are basically the same. 1959 uses V1a for the normal channel and V1b for the bright channel. 2203 cascades V1a into V1b. Here are the simplified signal paths: 1959 bright channel: input > V1b > volume pot > mixer resistors > V2a > V2b > tone stack > PI... 2203: input > V1a > preamp pot > V1b > voltage divider > V2a > V2b > tone stack > master volume > PI... V2b is a cathode follower that drives the tone stack in both. As you can see, a 1959 has 2 gain stages before the cathode follower, where a 2203 has 3. The mixer in a 1959 combines the two channels before going to V2. The voltage divider in a 2203 is in the same place and behaves similar to the bright channel mixer resistor in a 1959 (attenuates the signal and boosts high frequencies due to the bypass cap). Hope this helps. cylon185, NewReligion, axemane and 2 others like this.

11-27-2011, 09:20 PM	#6 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	Re: 1987/1959 VS 2204/2203 Preamp As stated earlier I think I found the correct Schem for this 2007 model 1987XL. I still need to compare it but the schem shows the Cathode resistors for V1A, V1B and V2A all to be 820 and V2B @ 100K Kind of ODD I thought.

11-27-2011, 09:23 PM	#7 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	Re: 1987/1959 VS 2204/2203 Preamp So the voltage divider on the 2203 allows for the cascade. What function does the mixer resistor carry out on the 1959/1987? Also, If I decided I wanted just a bit more hair/gain I could lower the value of V1B cathode resistor? I'm a NewbTard.

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11-27-2011, 09:48 PM	#9 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	Re: 1987/1959 VS 2204/2203 Preamp New England Amp Tech and Builder? Sounds Great, congratulations Joey. My interest here is to simply add just a little saturated gain without killing the amp. I had the 2203X sounding better than ever but just was not my cup of tea.

11-28-2011, 05:48 PM	#14 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	Re: 1987/1959 VS 2204/2203 Preamp Outstanding Sir! JV, thank you for taking the time to explain some of the major parameters in addition to the importance of frequency shaping, and clipping thresholds. Much to think about and organize into my notes. Sometimes intellectual property is priceless. Now I need to figure out which Schematic applies to this head as I found a few which differ. That can toy with a newb like me. David

11-28-2011, 06:42 PM	#15 (permalink)
Lane Sparber Senior Member Join Date: Apr 2010 Location: Queens, New York Posts: 2,492	Re: 1987/1959 VS 2204/2203 Preamp Also remember, David, that while changing one gain stages' topology can alter the tone shaping of that particular stage, it's best to understand the amp as a whole and absorb it all (e.g. how each stage is designed to function and shape the sound of the amplifier) before changing anything. For example, the SECOND stage in a classic 2203/2204 preamp is biased coldly - ICE coldly with just a single, unbypassed 10k resistor. This takes the "warmer" signal and then sends it clipping into the OPPOSITE cooler end of the spectrum. As a matter of fact, IMHO this stage having its' bias point at such an extreme is part of the reason most say that this amp doesn't "clean up" well. After this stage, the signal goes through one last "warmer" gain stage biased by an unbypassed 1k resistor. So, just in terms of the various stages' bias points we can see an intricate warm-cold-warm thing happening, and understanding how these stages work TOGETHER gives us a much more informed opinion in terms of deciding how to mod an amp for tone, or else you're spending forever blindly swapping components until you "luck" into a sound you like! Hope this helps, and I'm sure Joey will nail me if I've mis-represented anything! -Lane NewReligion, RickyLee and TradAmpGuy like this. __________________ New York Guitar and Amp Tech...and NOT a guru! WARNING: Tube amps contain LETHAL voltages long after they've been unplugged. If you are not familiar with the safety procedures involved when working on high voltage circuits (such as how to safely drain the filter caps), then PLEASE take it to a tech to stay safe...and alive. Some of what I do (log in to Facebook): http://www.facebook.com/media/set/?s...4798875&type=3 Last edited by Lane Sparber; 11-28-2011 at 08:27 PM.

11-28-2011, 08:37 PM	#16 (permalink)
NewReligion Senior Member Join Date: Nov 2009 Location: Wringing That Neck Posts: 6,751	Re: 1987/1959 VS 2204/2203 Preamp Hi Lane. Great to see that you have stopped by as well. Great advice to consider the entire preamp section when targetting a desired result from modification(s). I do understand that less clipping/voltage drop/EQ changes in small quantities in different areas is much more pleasing to the ear than one huge alteration. Is the warm/cold/warm approach relative to the asymmetrical vs symmetrical clipping diode lesson we discussed earlier this year?

11-28-2011, 08:46 PM	#17 (permalink)
Lane Sparber Senior Member Join Date: Apr 2010 Location: Queens, New York Posts: 2,492	Re: 1987/1959 VS 2204/2203 Preamp Not really. That was a whole separate issue. Tube clipping is almost always asymmetrical in nature. -Lane __________________ New York Guitar and Amp Tech...and NOT a guru! WARNING: Tube amps contain LETHAL voltages long after they've been unplugged. If you are not familiar with the safety procedures involved when working on high voltage circuits (such as how to safely drain the filter caps), then PLEASE take it to a tech to stay safe...and alive. Some of what I do (log in to Facebook): http://www.facebook.com/media/set/?s...4798875&type=3

11-28-2011, 09:11 PM	#18 (permalink)
axemane Junior Member Join Date: Aug 2010 Posts: 5	Re: 1987/1959 VS 2204/2203 Preamp Wow this is a killer thread. I have learned a lot but yet still don't understand quite all of it.... Joey Voltage , you should write a book sir......You are always most helpful and your knowledge is endless it seems.

11-28-2011, 09:43 PM	#19 (permalink)
axemane Junior Member Join Date: Aug 2010 Posts: 5	Re: 1987/1959 VS 2204/2203 Preamp ??? where did my post go? check...test...

07-07-2012, 09:55 AM	#21 (permalink)
ramhi4x Junior Member Join Date: Nov 2009 Location: Former Metallica guitarist during garage band days Posts: 8	Re: 1987/1959 VS 2204/2203 Preamp So is a 2204/2203 just a 1987/1959 with an MV and a one wire mod so to speak please? __________________ Enough stuff to start my own music store, EAS (equipment aquisition syndrome).

07-07-2012, 02:54 PM	#22 (permalink)
hbach Senior Member Join Date: Nov 2010 Posts: 1,278	Re: 1987/1959 VS 2204/2203 Preamp Hey ramihi, They are very similar but one big difference would be the very cold biased second stage on the 2203/4. This stage will be the one providing most the preamp overdrive and will sound different that the two normally parallel warm stages of the 1987/1959 cascaded. Bit of an old thread, but a gem indeed!

07-07-2012, 06:01 PM	#24 (permalink)
Les Moore Senior Member Join Date: Mar 2011 Location: Stockholm Sweden Posts: 1,744	Re: 1987/1959 VS 2204/2203 Preamp Jusr love to read these kind of threads! Not at all getting it all, but bit by bit, maybe one day... Maybe. NewReligion likes this. __________________ Les Paul, Fender Highway One, Franken-Lead, homemade Stratocaster, Boss TU2, Fame pedalpower, Ibanez Tube Screamer, Korg Wah, Budwah, Voodoolab ampselector, Weber attenuator, Whirlwind A/BY, POG2, Holy Grail nano, JMP 50W `72, Super Lead 100W `69, Ceriatone JTM45, 412 cab, Twin Reverb http://www.gjutjarn.com Assumption is the mother of all ****ups. Anonym. He got up and smiled as he did a crouchingtiger, hidden drunkass moonwalk backwards into my wall. BillyBlades

07-08-2012, 07:08 PM	#26 (permalink)
Les Moore Senior Member Join Date: Mar 2011 Location: Stockholm Sweden Posts: 1,744	Re: 1987/1959 VS 2204/2203 Preamp Done that. About ten times Every time I get a little closer to understanding but I don´t think I ever will get to the level of you guys. I think that to be able to grasp the concept of the entire chain, like Lane was talking about, you should have a good understanding of electronics, how components work, how they interact and how a minute change in A has an effect on G. I´ve been trying to understand how caps work, how tubes work and so on, but I can´t seem to wrap my brain around the signal chain as a whole. But it´s so fascinating that I will never tire reading this stuff NewReligion and hbach like this. __________________ Les Paul, Fender Highway One, Franken-Lead, homemade Stratocaster, Boss TU2, Fame pedalpower, Ibanez Tube Screamer, Korg Wah, Budwah, Voodoolab ampselector, Weber attenuator, Whirlwind A/BY, POG2, Holy Grail nano, JMP 50W `72, Super Lead 100W `69, Ceriatone JTM45, 412 cab, Twin Reverb http://www.gjutjarn.com Assumption is the mother of all ****ups. Anonym. He got up and smiled as he did a crouchingtiger, hidden drunkass moonwalk backwards into my wall. BillyBlades

07-08-2012, 09:24 PM	#27 (permalink)
hbach Senior Member Join Date: Nov 2010 Posts: 1,278	Re: 1987/1959 VS 2204/2203 Preamp Hey Les, I know what you mean. As a hobbyist I also try to take in as much as I can. But end of the day what I need the most of, and don't have, is listening experience. Just having tried out how things sound and interact is the key. Once you have say a gain stage and a tone stack the interaction and the math is staggering (just remember the current in a cap is 90° of phase with the voltage or complex if you rather use that) and sims work nice for most things but a sim won't tell you how a guitar actually will sound through that amp.

07-08-2012, 10:08 PM	#28 (permalink)
Les Moore Senior Member Join Date: Mar 2011 Location: Stockholm Sweden Posts: 1,744	Re: 1987/1959 VS 2204/2203 Preamp Exactly. Forgot to say that. Experience! What does it mean soundwise to change the value of a cap or a resistor in this or that place? Film, carbon, mica? The variables seem to be endless. That´s the fun. The core of soundchasing __________________ Les Paul, Fender Highway One, Franken-Lead, homemade Stratocaster, Boss TU2, Fame pedalpower, Ibanez Tube Screamer, Korg Wah, Budwah, Voodoolab ampselector, Weber attenuator, Whirlwind A/BY, POG2, Holy Grail nano, JMP 50W `72, Super Lead 100W `69, Ceriatone JTM45, 412 cab, Twin Reverb http://www.gjutjarn.com Assumption is the mother of all ****ups. Anonym. He got up and smiled as he did a crouchingtiger, hidden drunkass moonwalk backwards into my wall. BillyBlades

07-15-2012, 02:22 AM	#29 (permalink)
dreyn77 Banned Join Date: Feb 2012 Posts: 996	Re: 1987/1959 VS 2204/2203 Preamp If you want to experiment open the control compartment in you GUITAR and change the capacitor going to the tone pot, change the pot value (the pot is a resistor) It's the SAME effect in the amp! and the pedals! also amplifiers. VERY boring simple stuff! they talk with 'hot' and 'cold' words so it sound more interesting than it is! HOT means HIGH CURRENT (high resistance) cold means LOW CURRENT (low resistance) An 800 will never sound like a Plexi, the current in an 800 has been CUT in HALF!!!!!!! a DSL has been CUT in HALF again, -75% (scaled down versions of the 'BIG BOY' Plexi) MY little 'park' transistor has the full Van Halen first album tone/ saturation etc... (every song) at a fraction of the ear damaging volume! Fully scaled down exact copy of the original. just run the park amp into a 'real' speaker and a plywood speaker box! No NEED to 'MOD' the amp by some 'tossa' who just RIPS YOU OFF! and TALKS SHIT to you while he's RIPPING YOUR MONEY from your POCKET!!!!!!!! Marshallmaniac likes this.

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