[avahifi_lj]

Please be careful with mods!

Recently I upgraded an amplifier with some "modifications" installed.  I imagine that the mods were done in hopes of improving the sound.  Unfortunately, however, the mods almost resulted in some serious issues.

The AC power cord was replaced with jack that allows different power cords to be used.  While the hot and neutral wires were installed properly, there was an issue with bare AC power wires and the connection points almost touching the chassis.  One of the bare wires was 1 mm away from the bare metal.  One good bump of the chassis would have resulted in 120V AC on the chassis.  The funny thing was that the internal wires in the new power cord are actually smaller than the wires in our factory power cord.

The AC jack installed has three prongs, which for most people mean that the chassis was grounded.  In this case, however, the ground is not connected to the chassis.  It would have been better to use a two prong AC jack so that others (future owners, for example) would know that the chassis is not grounded.

Other issues included improper grounding of the input signal, loose hardware, and poor solder connections (cold solder joints and blobs).  While none of these problems would cause electrical shock, the AC power wiring was a serious threat.

I know that hobbyists like modifying stuff; however, make sure you know what you are doing before playing around.  All of the AVA products have lethal voltages present inside of the chassis.  The most common is the 120V AC mains voltage.  There are, however, other high voltages in most of the products.  For example, anything with tubes will have 200+ volts, hybrid power amps have 280+ volts, tube amps have 450+ volts, and solid state amps can have around 70 volts.  All of these voltages can be lethal!!!

Please be careful!

Thanks,

Larry

[srb]

That's exactly why I avoid used modded equipment like the plague, the exception being if it is from a well known established professional modder with a warranty.
 
"I replaced the output caps with..."   NEXT!
 
"I replaced the power supply diodes with..."   NEXT!
 
Electronics is a great hobby, and if someone wants to modify equipment for themselves, that's fine.  But Buyer Beware on the used market.
 
Steve

[Bill Thomas]

     I cannot stress enough the importance of setting a practical, DEFINABLE "goal" when you are attempting a "mod" on an already well-engineered piece of equipment.  An UNREASONABLE and UNDEFINED goal is, "I want it to sound better."  better than what?  If you have decided the unit in question doesn't sound *right*, you MUST research the possible REASONS why this is the case, rather than blindly replace parts with some (supposedly) "high-end", "boutique" components.  Once you have discovered the reason your unit *might* be compromised, only THEN will you have an idea of what it will take to "make it better."

     Also, make SURE the unit you are considering "modding" is operating normally BEFORE you make ANY "mods."  Unless you have a baseline test to compare things with, you will be dealing with "feelings" rather than real, empirical evidence.

     But MOST importantly, recognize that SAFETY comes FIRST *AND* LAST!!!  I KNOW some folks just LOVE to swap out Power Cords.  (Not exactly *my* thing really, but you know who you are.)  ANYTIME you are dealing with wiring that connects to a "plug in the wall," there is the potential to "electrify" the chassis unintentionally.  KNOW WHAT YOU ARE DOING and PERFORM YOUR WORK AS THOUGH YOUR LIFE DEPENDS UPON IT!

     In the final analysis, it DOES!

Sincerely,

Bill Thomas

[trebejo]

Safety, please!

As Frank wrote on some post once, dead audiophiles do not provide good repeat business. 

Now, aside from not wanting people to fry themselves, there is another point vis-a-vis these particular modifications. If you are going to mod, you should aim for the low-hanging fruit--units assembled by robots, or employees that are paid wages like robots; then onto units made of ridiculously inadecuate parts that tend to fail.

I cannot imagine that a Van Alstine unit provides such opportunities. After all, modding Dynacos was one of Frank's bread-and-butter products!

You want to mod a modder? A heck of a modder like Frank? Please. You might as well stroll down to the Met and give singing lessons to the tenors. 

[Big Red Machine]

Why is the ground wire not connected to the chassis?  How is that safe?

[Listens2tubes]

The bare power wires is irresponsible when heat shrink and liquid electrical tape are available. OTOH I don't hear any reason to add/change AVA designs. Frank puts much time and effort into the development of these gems and he trys many different components and combinations before releasing them for our enjoyment. He often continues to find new improvements over time that he passes on freely to his customers.

[jhm731]

I agree that you shouldn't mod avahifi equipment.

If you don't like the way a stock unit sounds, you should return it for a refund
under avahifi's 30-day satisfaction guarantee.

[TomW16]

I think that Larry's sage advice is warranted.  If, however, we are most concerned about safety, the chassis should be grounded to avoid any inadvertant voltage on the chassis but I understand that this can cause additional noise. 

Tweaking for those that have the knowledge and expertise is fun and rewarding but safety should be a priority.

Cheers,
Tom

[satfrat]

I think that Larry's sage advice is warranted.  If, however, we are most concerned about safety, the chassis should be grounded to avoid any inadvertant voltage on the chassis but I understand that this can cause additional noise. 

Tweaking for those that have the knowledge and expertise is fun and rewarding but safety should be a priority.

Cheers,
Tom

But if the AVA chassis isn't grounded to begin with using only a 2 wire power cord, is it a smart thing to do to be adding a ground chassis wire to the design when installing an IEC terminal? 
 
Cheers,
Robin

[TomW16]

But if the AVA chassis isn't grounded to begin with using only a 2 wire power cord, is it a smart thing to do to be adding a ground chassis wire to the design when installing an IEC terminal? 
 
Cheers,
Robin

I think that we're getting awefully close to the power cord discussion.     Why would you put an IEC terminal on?  If it were me and I wanted to test power cords, I would ground the chassis.  Of course, this might increase the noise and any possible benefit of a different power cord.

Cheers,
Tom

[jhm731]

I think that we're getting awefully close to the power cord discussion.     Why would you put an IEC terminal on?  If it were me and I wanted to test power cords, I would ground the chassis.  Of course, this might increase the noise and any possible benefit of a different power cord.

Cheers,
Tom

If you like the sound of your AVAHIFI gear and wanted to test different power cords, you could connect the ground from the IEC connector to the chassis, and install a ground lift switch.

Also, always mount the the IEC connector with the ground pin facing down.

[trebejo]

Doodes, you are so retro!

I have a killer mod for ya. Don't do anything to the AVA power cords, BUT stick one end of a superduperultramagic wire into the little hole in the wall outlet that is otherwise unused and wrap the other end of the wire around the little holes on the top of the chassis! YES!!!!!!!
 

[Listens2tubes]

Doodes, you are so retro!

I have a killer mod for ya. Don't do anything to the AVA power cords, BUT stick one end of a superduperultramagic wire into the little hole in the wall outlet that is otherwise unused and wrap the other end of the wire around the little holes on the top of the chassis! YES!!!!!!!
 

Would this create or fix a ground loop?

[rcag_ils]

I am trying to understand the owner of this piece of equipment more than the mod that he put in.

1. He owns AVA equipment, so it's reasonable to assume that he read the AVA Circle.

2. If #1 is true, then I am sure that he read about how much AVA's against fancy power cords.

3. With all the information that he read about fancy power cord in the AVA circle, he still swapped out the AC cord and did a poor job of it........

My conclusion is he's either can't read, or he's trying to tell Frank something, but if he wants to do that, at least he should have demonstrated some good workmanship, so he is one rebellious AVA equipment owner that can't solder.

Am I over-analyzing this or what?

[charmerci]

I am trying to understand the owner of this piece of equipment more than the mod that he put in.

1. He owns AVA equipment, so it's reasonable to assume that he read the AVA Circle.

2. If #1 is true, then I am sure that he read about how much AVA's against fancy power cords.

3......

Am I over-analyzing this or what?

It could be an old Van Alstine design. I know many people have made mods on old Super Pas', PAT-4/5's for at least 30 years. Frank used to publish design mods in his old Audio Basics newsletters. Some people will send an old Hafler amp for AVA to upgrade, etc.....

[satfrat]

I am trying to understand the owner of this piece of equipment more than the mod that he put in.

1. He owns AVA equipment, so it's reasonable to assume that he read the AVA Circle.

2. If #1 is true, then I am sure that he read about how much AVA's against fancy power cords.

3. With all the information that he read about fancy power cord in the AVA circle, he still swapped out the AC cord and did a poor job of it........

My conclusion is he's either can't read, or he's trying to tell Frank something, but if he wants to do that, at least he should have demonstrated some good workmanship, so he is one rebellious AVA equipment owner that can't solder.

Am I over-analyzing this or what?

There is nothing to analyze, if a customer wants an IEC terminal and is willing to accept the consequences (no warranty), it's his right to do so all tho I'd feel a little guilty sending it back to Frank to begin with. My only question is of the safety of introducing a chassis ground to an IEC terminal when the design didn't call for one. Not adding the IEC ground negates even bothering with this mod, unless the power cord itself doesn't have a ground on it either.
 
It's also concievable that this unit was bought used and already modded in which case all your analyzing is irrelevent. Who knows what the actual circumstances really are? 1 thing I'm absolutely sure of, this isn't the 1st AVA piece of gear that has had an IEC terminal mod done to it and it won't be the last. 
 
Cheers,
Robin

[Bill]

There are a lot of people out there in the audio world who drool over the mere mention of the word modified. If the piece of equipment being advertised goes one step further and mentions heavily modified, then it warrants serious consideration. The guy modifying this particular piece of equipment probably has no background in electronics and after indiscriminately swapping parts (while smoking a huge joint of course) purports earth shaking improvements. He calls his buddies and shouts " this preamp blows the doors off the stock unit man"! BEWARE

[gerald porzio]

When was the last time anyone noticed a modder publishing measurements to give his claims credibility?

[rcag_ils]

"heavily moded" = "stay away from it" in my book. I prefer originality.

[Wayner]

Many brands of equipment that have only a 2 conductor cord do not have the chassis grounded. I have a brand new Onkyo T-4555 HD tuner, Sony XDR-F1HD HD tuner, Marantz CD5400 CD player, and every turntable that I have, without a grounded chassis. In Frank's case, the line leg of the 120 volt hot side goes immediately into a line fuse as I'm sure is the case with all other 2 wire components. The ground is simply not necessary, even with a metal case (as all components I have mentioned) and introducing a ground to the case, while not "unsafe" may cause noise or ground loops typically associated with 3 prong components. I am simply amazed how many people praise Frank's equipment, but then chastise him for not offering an unnecessary grounded scheme.

If you will notice on a polarized outlet, how many think the wider vertical slot on the left is the hot? Well, it's not, it's the neutral. Then I wonder how many DIYer's have the neutral side fused and the hot side unguarded?

Wayner