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Discussion Starter · #1 ·
I responded to a thread earlier today by Ray about electrolytic capacitor changeouts. After my response I did a search on this wonderful forum and found a number of threads on the same subject. Now this will unfortunately show my age, but what we all have been doing was developed, if my memory serves correctly, by a man named Jung in a series of articles he did for Audio Amateur magazine in the early 1980's.

Mr. Jung named this process POOGE as I recall. I'll probably butcher this, but I think it stood for "Progressive Optimization Of Generic Electronics", or something like that. It was based on the fact that all passive electronic devices (resistors, capacitors, inductors) actually behaved far from the ideal, and that by proper selection and replacement of these devices to ones that more closely represented the ideal, the performance of audio preamps and amps would improve.

Since that time I have worn out more than one de-soldering tool in search of the Holy Grail of perfect audio and video by this process. Are any of you familiar with these articles, and is this where you started your mods?

BTW, probably because of the much higher frequencies involved, while poogeing of audio equipment makes subtle but noticeable improvements, with analog video crt projectors, the difference is far more noticeable in my experience.

Thanks,

Bob
 

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Sir


Although I am sure there are some gains to be had that way, I am not sure that such practices are cost-effective. Most of the mods I do are from factory engineering bulletins; the fan noise mod for Marquee was developed here at E-Tech with the help of an accoustical engineer, Larry Clauss.
 

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I'm not sure how Ken (KBK) got started, but I'm glad he did. I have used his experience and recommendations to improve my ECP400 and let me tell you, it is an amazing night & day difference. I'm scared to ask how many renditions he went through to get to the final stage, but it definately was worth my time.
 

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Some day we will get Tim to see the better light. The man's name I believe was Walt Jung. He did some articles I believe with an italian by the name of Bobberly, a rather brilliant solid state designer. As I remember this audio mod pathway, it sort of started with a seminal article on capacitors by Richard Marsh in the now defunct Audio Magazine. Basically teflon, polystyrene, polypropylene in decending order of characteristics favorable to better audio. Low DA, low ESR. Talked about non polar and biasing electroylitics. We all stated replacing poor caps with expensive better ones. Bypassing large value electrolytics and even props with high quality film caps. Led Marsh to develope the multicap--sort of ten small caps in parallel rolled into one tube. Metal film resistors to lower noise, litz wiring. Bigger PS caps. Peter Moncrief also had a lot to do with this.


With CRTs some of this is the same, some is different. With Marques the build and parts quality is much better than the stuff we were modding back then. We were working at much lower voltages and we did not have switched mod PS. Still the local PS feeding the transistors can be improved. The RGB blocking capd. Better HF decouplings caps. Only a few here like Ken have been playing with this stuff. The boards are crowded and there is not much room for parts substitution. Better parts are usually much bigger. RF is much more of an issue. Still I am getting that good ole Pooge feeling going inside of me to make my 9500LC even better. I know my buddy MP knows how performance can be improved by replacing old caps with new ones and inserting nore thermally stable resistors in critical locations. I am not sure I have convinced him re better parts is better video, but we shall see.
 

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Funny, I totally forgot that term.


No, I do not POOGE, ever!


Salutations to those that do, but I do not have the time, and I never want to be accused of screwing up a projector's long term reliability by me messing with the inner workings to get a set to 'my' standard.


Electrohome focus resistor mods and Barco solder joints excepted, I do not mod projectors.


I look at the high end Parasound equipment designed by John Curl of great fame and high repute.


It may be well designed, but built in the crappiest of factories. Maybe it's changed, but being the Parasound warranty depot for 4 years from about 1990 to 1994 yielded some of the worst built crap I have ever seen. Warranty failures were always construction and not parts failures.


Then there were the audiofool guys that brought in blown up power amps that they had modded; I remember one guy that replaced every single 0.1 uF cap with a huge mother of a 1.0 uf Cap at 600 volt (we're talking +/- 15 volt supply rails here), and he had leads hanging off the boards everywhere. We flat out rejected even looking at it, and boy was he pissed!


So yes, guys like KBK have lots of merit in doing mods and research, but frankly, given a heavily modded projector or other piece of equipment, I'll turn down repairing it, referring it back to the tech that modded it in the first place.


Since many of these mods are done on a single piece, hw can one tell if long term reliability is not compromised by now massive turnon surges due to 10X the amount of filter caps in a set? Now you're faced with trying to find out if a mod caused the set to fail, or whether it's an actual original component failure.


I'm busy enough fixing component failures without having to have other variables thrown into the mix, thanks!..:D


Curt
 

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On second thought, a better reply would be: (in your best Monty Python accent)


Q: Do you POOGE?


A: Why that's a rather personal question sir!


Curt
 

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Now I can tell you stories of putting so large main filter caps on a Hafler 200 that they protruded the case by 15 inches and I had to install a relay controlled shunt power resistor to prevent openning my main panel circuit breaker on turn on. Seriously, most products can indeed be improved by substituting higher quality SAME VALUE parts. Particularly caps. Ken is not crazy, but I am sure he would admit it would help. Electrical engineers back in those days would say a cap is a cap and many refused to learn from Richard Marsh and Walt Jung. Ken and Mr Williams have seen the better light from improving the parts on a Marquee. Sure you can indeed screw things up but if you know what you are doing and exercise good board techniques there should be no problems. These older projecyorss are not under warranty anyway. Try a Spectral amp and power amp to see what employing the very best parts from the get go gets you.
 

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Discussion Starter · #9 ·
Mark - It is obvious you remember those articles, and I forgot the input that Richard Marsh had. I too remember hanging those big cans out the back of an old Dyna 400 and have a TD relay short across a series resistor to hold back the current inrush at startup!

I don't think that the engineers that designed our precious crt projectors missed the boat, I think they have to design a product that comes in at a certain price range to maximize profits. If they didn't understand the importance of capacitors at the transistors, they would not have even put them there along with the ceramic disc bypass caps. What we are talking about is just going back into the machine and choosing parts that they could not put in because it would cost too much to sell in a competetive market. If you look at the high end audio industry since the work of these people, the designs follow their advice including two stages of regulation with the second stage being a three terminal regulator right at each active device! These guys deserve a lot of credit.

What I am saying is that what they did is much more important in a video circuit than it is in an audio circuit because of the higher frequencies involved. No matter how linear the frequency response of an active video circuit is, it can only be as linear as the power supply feeding it. The internal impedence of the power supply system is not very good at these frequencies when you consider the many feet of wires from the PS to the board and then the traces on the baord to the transistor. It's OK for low frequencies, but not at video frequencies. That is why there are PS caps at the transistor - to try and reduce the impedance of the power supply at that point. We are just doing what the design engineer wanted to do in the first place. We are hobbyists, and we all want to get the most performance we can out of our hardware, and this is one fun way to do it. I can tell you that my first mod to my GP-5000 was to replace both sets of RGB caps from 100MF non-polar electrolytics to 100MF poly's. Yes, I had to strap all six of them to the inside of the chassis and run coax leads to the board, but the end result of this effort was much more than subtle. If, and when I get the time, I will go through the entire projector, Poogeing all the way! Fortunately I have a spare GP-5000 that I can use to do one board at a time.

Curt - I agree with part of what you are saying. From your experience you have had customers bring in equipment they have butchered. I profess that it is not the concept that is wrong, but the execution. Also, done properly, poogeing will increase the reliability - not decrease it.

Thanks,

Bob
 

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Hello All, I am a new member of the forum, and I am enjoying the volume and depth of the posts here. I've been a audio amateur since the late seventies, and have the articles from Audio Amateur and Audio Magazine. The point of the series was that components matter sometimes as much as topography (sp?), and were quite a eye opener. I still have and use a Hafler DH200 that has the mods as written. I've been quite imtrigued by the modifications that have been suggested by KBK. So much so, that when I purchase a front projector I intend to pursue his plan as well. Has anyone ever assembled a FAQ for all of these mods? A parts list been developed? I love to hear about your collective efforts to improve these machines.


Mark Meyer
 

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Discussion Starter · #11 ·
Mark - Just go for it! If you use the same philosophy and criteria you used on your audio amp, it will work even better on an analog (crt) projector. Get your schematic out, the latest Digi-Key catalog and any source of good film capacitors and you are in business. You will need a desoldering tool and plenty of time!

Thanks,

Bob
 

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I think this guy may have been the original POOGER! I found a little bio for him here. He may have been a POOGER because his modification did not necessarily make the item better, just cheaper.


Mike
 

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I actually developed some of the early modifications for the Hafler circuits, which I sold to a guy who made it part of his business. Most of what we did back in the late seventies was simply parts substitution, and most such mods were based at best on anecdotal evidence and some subjective listening sessions. I still believe that those modified units sounded better, but I don't pretend the work behind the mods was scientific.
 

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Discussion Starter · #14 ·
Mike - MUNTZ? Hey, gimme a break! Muntz was a maniac, and Jung/Marsh are both avid hobbyists with PHD's in engineering. They know from where they speak just as many of the knowledgable people on this forum. Muntz's car wasn't bad looking though, and it probably had an 8 track in the back seat.
 

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Marsh is not a hobbyist. He is a retired Lawrence-Livermore (forgive my spelling please) physiatrist. He developed the ultracap, has done video design work for MIT (the wire company), and now has a company which builds great sounding audio amps and preamps. I do not sell them yet but was greatly impressed by their sound quality at the last CES.
 

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Steve,


There were a number of articles written about the Haflers, what guy was that ? I think if you take the time to read Marsh / Jung work(s), there was a great deal of science behind it. Walt's pooge articles were attempting to show that caps and resistors, imparted a sonic signature to electronics that they were installed in. There were a lot of investigations into wiring types and conductor and insulator contributions as well. All of these works contributed to the advance of the state of the art as we knew it then.


The thing that excites me about KBKs work is the same willingness to improve upon existing designs, and making those mods acessable to the hobbyist.
 

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We nearly got in trouble there, in the Chris Stephens thread. The horror stories of modketeering where starting to stick out. I have blown mosfets to a dead short, and barely realized the difference. I modded an amp so much, that when this happened, I think it remained unoticed for six months. i opened the amp, and saw that a transistor had blown it's brains out. i measured it, and it was a dead short. It was one of the FET outputs. (2SK135)


I nearly killed myself once, with a dyna 70 and 10,000uf at 525VDC. (the table collapsed, and I rushed to save my mullards) 525V. ouch.


Anyway, I never published any or my findings or fun here on the forum out of respect to CRT resellers.. specfically ones that are modified. Also, I have too many directions on my plate. I love them all, but some have to be shoved off the table, and relegated to hobbies. The door was opened on my attitude by the thread I speak of, and, well, I just want to do what I have fun doing. CRT is a mature technology. It's advances are left to those with the will to push it to total refinement. I told WM once that I did not want to make just any CRT projector, I wanted to make the LAST CRT projector. Take what someone thinks is the very best, and show them what it can really do.


Cost is NOT a factor. Quality is.


This has not much to do with commercial viability. Or service by anyone but the modifier. Intelligent modifications will not breach reliability. Failures WILL go up.. it is just the part breakage pattern that technicians are used to can shift about a bit. I can hear what Tim and Curt are saying, and certianly cannot blame them. I cannot imagine the nightmare of going into something like a modified projector, as a service problem, if you are not the one who did the work. The entire patteren of thinking about the unit would turn into a forgein language.


Anyway, my eyes are killing me. ihad to take the headphones off, and put the wireless keyboard on top of a speaker,and type standing, about 3 feet from the screen. This is the only way I can see the text in these damn small windows on the PJ desktop at 1920x1200. it's clear though. the letters have no edging or color problems. the edit window is 25" diag., and I was trying to read it from over 11 feet away. The letters are 8mm tall. Very tiny. I want to get back to seeing what this thing can do, so, back to visuals....
 

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Speaking of mods, a fully whacked (maximally modded) Bruce Moore designed Pre-amp will still beat the pants off of ANY, repeat, ANY pre-amp out there today. So much more correct sounding, it just ain't funny. Bruce be tube god. Simple, pure, dynamically scaled, tonally balanced. Pace, rythm punch, all in spades. Hell a 25 year old PARAGON E has the ability to TRASH just about anything out there, if ithe Paragon has been modifed.


When I grow up, I want to be a Paragon.


PS: Some may disagree, but you still haven't managed to hear what audio sounds like on a real speaker. The PJ mods I do are a sick joke compared to the loudspeaker work.
 

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Wow. I used to sell Bruce Moore designed products in the 80s. I think he was partnered with a guy named Scott Franklin. Bruce was the guy they kept in the closet so dealers wouldn't be scared away. He was easier to understand than Ken sometimes because he indeed was a man of few words. I do not think Scott fed him enough. This is all sort of a hazy memorary. Bruce could design tube circuits that delivered.


Ken. You must be one old dog like me (56). Woof.
 
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