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Double Bass Walter Woods Amp repair

#21
Rockmore said:
...ANY electrostatic capacitor, especially those made in the 1960-1995, only have a shelf life of about 10-15 years, and use life of about 10, especially in those years. The 'old' MI series HAS TO BE RECAPPED, as those ltyics were not that good to begin with and all started acting like resistors about 1991.
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Rockmore said:
Has solely to do with the average quality electrolytic capacitors that now have all expired, are acting like resistors, and need to be replaced.
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Rampant oversimplification. I have decades of counterexamples and the point isn't even worth arguing. Indeed, it is true that electrolytics do deteriorate with age but you have grossly overstated and overgeneralized.

Now, I have no experience with WW amps but I abhor the practice of not providing schematics and obscuring component values. There have been plenty of esoteric amplifier designs the manufacturers of which never adopted such practices. Personally, I wouldn't buy an amp that I was prevented from repairing and/or servicing myself or paying any of a number of qualified shops to repair and/or service. I understand that others would and do. To each his own in that regard.
 
#22
FWIW I have a 15 year old Walter Woods amp that sounds terrific with plenty of headroom and low-end girth, and is totally solid. There is absolutely no reason to replace the original electrolytic filter capacitors in this amp.

To my knowledge, Walter has never provided information about his power supplies, however, the components in the audio section of my 1997 WW Electracoustic amp, such as IC's, capacitors, and resistors, are all clearly marked.
 
#23
drurb said:
Rampant oversimplification. I have decades of counterexamples and the point isn't even worth arguing. Indeed, it is true that electrolytics do deteriorate with age but you have grossly overstated and overgeneralized.

Now, I have no experience with WW amps but I abhor the practice of not providing schematics and obscuring component values. There have been plenty of esoteric amplifier designs the manufacturers of which never adopted such practices. Personally, I wouldn't buy an amp that I was prevented from repairing and/or servicing myself or paying any of a number of qualified shops to repair and/or service. I understand that others would and do. To each his own in that regard.
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Gross negligence, overstating, and plain ignorance. Obviously knows nothing even about basic electronics they teach in the 10th grade of most public HS even. Scary.

Is anyone in this thread NOT on drugs? The schematics for the WW amps have already been stated commonly available- inside the head themselves, if you can use a basic screwdriver to remove the non-vented cover, which it seems most of you can't. Isn't about schematic availability- you have to look for yourself at each individual 'lytic cap and see what's installed 25 years ago.

Showed this thread to some of my colleges- couldn't believe it. "Heatsinks and amps you can fry bacon on". "Hey it still works after 15 years no probs", etc. Guess ignorance is bliss till it frys right in front of you. There is no debate or question by anyone anywhere that every single WW MI series amps are already 10-15 years past the bare minimum use and safety life of the 'lytics in them. You can read this, but what's the point for most of you- you are the types that probably think you have to have a "certified" tech to take a lug nut off a basic car wheel/tire. S-C-A-R-Y. Invalid Link Removed

Any of you under 80 years old and can access youtube? Watch 12 years replace electrolytic capacitors in anything. Is IS that basic and simple. Doesn't have anything to do with tech specs, engineering, design, dust, dirt, or the abuse and ignorance of the outdated designer and users. You take the amp apart, use your own eyes and verify each lytic by site, find suitable replacement(s), and replace them. Sorry this is so waaaay beyond you "tenured" musicians...
 
#24
"Doesn't have anything to do with tech specs, engineering, design, dust, dirt, or the abuse and ignorance of the outdated designer and users. You take the amp apart, use your own eyes and verify each lytic by site, find suitable replacement(s), and replace them. Sorry this is so waaaay beyond you "tenured" musicians..."

If that is the case, why are you asking for info from anyone who has done it? Why would you care to repair/refurb/upgrade an outdated design for outdated users? It must not be your amp. Are you a tech working on an amp for a customer? I am just trying to figure out your angle/vendetta.
 
#25
Among TB'ers, drurb is someone who has some experience digging into old gear, and who I expect would have no problem re-capping a bass amp.

I've interacted with quite a number of bassists. And this isn't a dig at anybody, but it's my own observation that most folks would not be comfortable or qualified to re-cap an amp. It's not brain surgery, but one of those things where you take a process with 10 steps, give each one a 90% chance of success, and you end up being more likely to fail than succeed. You need to have your skills up pretty close to the 100% range before I'd trust you to do this safely.

I've got a picture of the inside of a WW amp. In fact there's a thread over on the BG side with "gut pics" that folks have taken of their amp innards. It's one of my favorite threads, because I'm fascinated of this stuff. Now I don't know which model of WW amp I'm looking at, but the way it's constructed, servicing it would absolutely not be for the faint of heart. In fact of the bass amps that I've seen, many would be difficult to work on without a fair amount of experience and knowledge of electronic assembly. Just getting at the solder joints can be a chore, and you've got a finite chance of damaging the board when you remove the old caps.
 
#26
I'm not on drugs.

I can change a tire.

I can strip an engine down to the block and rebuild it.

I can take a pile of scrap wood that used to be a bass and make it back into a bass.

Can you do anything besides troll people with real experience?

And, utterly contrary to your point, I relied on WW amps for 10 years while I was still using amps and never had one melt down in front of me. So I choose to believe my lying eyes.

Friggin' EEs.
 
#27
Rockmore said:
Gross negligence, overstating, and plain ignorance. Obviously knows nothing even about basic electronics they teach in the 10th grade of most public HS even. Scary.
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I think perhaps you should check Durb and FDecks User Profile. One's a pre amp designer and works for a tech company, and the other teaches at the University level. Since you choose not to fill out yours, we have no idea who you are or what your qualifications are

Rockmore said:
Is anyone in this thread NOT on drugs? The schematics for the WW amps have already been stated commonly available- inside the head themselves, if you can use a basic screwdriver to remove the non-vented cover, which it seems most of you can't. Isn't about schematic availability- you have to look for yourself at each individual 'lytic cap and see what's installed 25 years ago.
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Now, you're just being insulting, and even if you were right, which you may be, I doubt that anyone would listen.:rollno:


Walter only provided schematics for the MI-100's, after that he quit including them. All the 100's of amplifiers he built later have no schematic.

Rockmore said:
Showed this thread to some of my colleges- couldn't believe it. "Heatsinks and amps you can fry bacon on". "Hey it still works after 15 years no probs", etc. Guess ignorance is bliss till it frys right in front of you. There is no debate or question by anyone anywhere that every single WW MI series amps are already 10-15 years past the bare minimum use and safety life of the 'lytics in them. You can read this, but what's the point for most of you- you are the types that probably think you have to have a "certified" tech to take a lug nut off a basic car wheel/tire. S-C-A-R-Y. Invalid Link Removed
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Since you refuse to fill out a user profile, we have no way of knowing who you are, or who your colleagues are.

Rockmore said:
Any of you under 80 years old and can access youtube? Watch 12 years replace electrolytic capacitors in anything. Is IS that basic and simple. Doesn't have anything to do with tech specs, engineering, design, dust, dirt, or the abuse and ignorance of the outdated designer and users. You take the amp apart, use your own eyes and verify each lytic by site, find suitable replacement(s), and replace them. Sorry this is so waaaay beyond you "tenured" musicians...
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Perhaps, you judge us to harshly. I regularly inspect my both my Woods Amplifiers, blow out that dust, clean the pots and call Walter if it needs something. Since I'm kind over the phone he always calls me back.

I also have an Ampeg B-15N(C) built in 1964. It has new caps, the output transformer has been replaced, a Weber Cooper Cap solid state rectifier sits in the tube socket where the old 5U4 used to reside, and the 6L7's and 6L6's have been replaced as well. So even though I am 62 year old "tenured musician", I take care of my equipment. The only thing that I've had to do with my personal MI-100-8 which now belongs to someone else, was send it to Walter to have the AC power cord replaced. When I originally purchased that amp in 1980, the SMPS was faulty and died, Walter fixed it, and payed the postage both ways. I had it back in three days time. :)
 
#28
Rockmore said:
Gross negligence, overstating, and plain ignorance. Obviously knows nothing even about basic electronics they teach in the 10th grade of most public HS even. Scary..

Is anyone in this thread NOT on drugs?

Any of you under 80 years old and can access youtube?
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Perhaps I shouldn't respond to someone who is so rude and assumptive but, frankly, I find this a bit entertaining. Rockmore, you seem to be parroting the lay articles of the type to which you linked. You are doing what many do who do not have a deep knowledge of a subject. Specifically, you are applying simple principles while failing to understand where they matter. Yes, it is true that electrolytics deteriorate. That's a fact. The question is to what extent they can deteriorate before circuit performance is impacted substantially. Your posts are a prototypical example of "A little knowledge is a dangerous thing."

Having studied EE while in graduate school, I think it's fair to say that I really do have an understanding of these concepts beyond the 10th grade level. I am well under 80 years old and I am not on drugs.

fdeck is correct that I'd have no problem recapping an amp. In fact, I began doing that about 40 years ago (Was that prior to your birth? Just curious). I have restored, recapped, and serviced vintage tube equipment and more solid-state amps than I can recall. I have designed and built laboratory-grade amplifiers as part of my "day job." My "tenure" as a musician is as a very dedicated amateur semi-pro.

Rockmore, I don't know what is your background or expertise. I can't imagine you've gone through the process of reforming dielectrics but maybe you have. Perhaps you haven't been able to see first-hand the operation of older electrolytics on a good scope and seen their actual effects on circuits via sophisticated spectral analysis. If you had, you might understand why it is not wise to assert that all these folks with WW amps greater than 10 years of age should, necessarily, recap them or have them recapped.

Spewing generalities and insulting people will not win you many friends here. In addition, you are wrong to assume that everyone here is simply a musician who can't handle a wrench or, for that matter, a soldering iron.

Given your attitude, I doubt I will convince you of the error of your ways and your thinking. That's just fine. I'm quite comfortable with the formal and practical knowledge that I have that has been gained over decades and continues to be gained.
 
#31
I refilled the bowl for us. :)

Homemade-Popcorn-Ultimate-Butter.jpg
 
#36
He who laughs last.

3 months and 30 hours later on the complete recap of the blaze' Mi-800-8, it couldn't sound better. Owner himself, one owner, states it sounds better than new.

Replaced every single electrostatic capacitor with Nichicon KZ, KA, or Elna Silmic II audio grade capacitors, and with stacked metal film for every single old electrolytic on the control board for the pots.

Every single WW out there is 15-25 years past the use life of the average (and we mean AVERAGE) general grade electrostatic caps that old WW used in his original builds. It is that simple, that accurately identified, and now commonly known.

Actually TALKED to WW live on the phone. To say the least, a very, very sad and scary experience. WW is in his extreme old age dementia stage, and his psycho babble and rants are 'out there', to say the least. To say the most, his flat out denial and non-awareness that modern day audio grade capacitors exist (that far exceed the general grade caps he originally used that are now dried out and completely out of spec) was so out of touch with reality, that contacting him for any to-date repair that might involve the specs and types of transistors he used in his engineering now would not be reliable.

We had a 15 year old 9th grade student assist in the simple and basic recap of the Mi-800-8. Simple. Very simple. Even a child student of that age and demographic was able to help with the recap.

The 'reward' and tangible results far exceed even what we expected. So for those of you that deny your MI series bass amps need a complete recapping, please, use them more as-is and burn them to hell. Let them sound like the worn out pieces of do do they are with electrostatic caps that expired 15-25 years ago. The pro upright jazz bassist that uses this recapped gem we created bi-weekly couldn't be happier, and also commented several times the amazement of the ignorance and type of people who did not contribute to this simple recap, and mainly from the feedback of stagnant members who commented negatively in this thread.

He who laugh last. We proved just about every single one of you wrong.
 
#39
Before and after pictures Rockmore, I'm surprised you haven't included any here....seems that the amp in question might be a figment of your imagination otherwise. If you are so gung-ho on proving your point, making a youtube video of the whole process, demonstrating the "before and after" with sound clips, would have been helpful to your convictions that WW amps are all in need of service now. That would have been helpful to anyone who might like to try the service themselves. As it is now, you claim that you know more about the WW amp than Walter himself.
 

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