AVI Lab Series Modifications (less is more)

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Dr Bunsen Honeydew
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Re: AVI Lab Series Modifications (less is more)

Unread post by Dr Bunsen Honeydew » Sat Jan 20, 2018 10:39 am

"Inhaling cadmium-laden dust or fumes quickly leads to respiratory tract and kidney problems which can be fatal (often from renal failure). Ingestion of any significant amount of cadmium causes immediate poisoning and damage to the liver and the kidneys. Compounds containing cadmium are also carcinogenic.

The bones become soft (osteomalacia), lose bone mineral density (osteoporosis) and become weaker. This causes the pain in the joints and the back, and also increases the risk of fractures. In extreme cases of cadmium poisoning, mere body weight causes a fracture.

The kidneys lose their function to remove acids from the blood in proximal renal tubular dysfunction. The kidney damage inflicted by cadmium poisoning is irreversible."

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ABallagh
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Re: AVI Lab Series Modifications (less is more)

Unread post by ABallagh » Sat Jan 20, 2018 11:50 am

As I said you can say what you want, recommend what you want, there is nothing wrong with what you did or said regarding the forum BUT so can I and any member can do the same. I see that as constructive criticism, you see it as trashing.
Fair enough, probably had a few too many last night and got a bit over sensitive, sensible head back on now. On the cadmium subject, are you saying using a volume control with these things in is dangerous? I'm not arguing with the facts, cadmium is very very bad but lets take it in context, I bet you are more likely to die from a thousand other dangers on our planet than from using an LDR, even less likely if your buying the end product, I'm not saying that's a good excuse, its just that we make choices every day that are life threatening, the smoke from cigarettes contain cadmium but you dont see the eu banning them. On the subject of how they sound, I think you will find more people saying LDRs form the best volume control than there are saying there shite.

1/ crossover - throw the bloody thing away and do it properly by matching and doping
I have been looking for the sticky on this? I do like the idea. As I said I have toyed with it some time ago but I never knew about the doping.

2/ I have no problem with your amp, for its type it is one of the better ones, it is just unsuitable to do the things I have done i.e. NVA principles to it, as I said better sell it and start again if you want to go down the KISS route.
Can you recommend a suitable candidate that can be picked up second hand?

Could you please also tell me the speaker cable capacitance you recommended for NVA owners? I read it and forgot.

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Dr Bunsen Honeydew
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Re: AVI Lab Series Modifications (less is more)

Unread post by Dr Bunsen Honeydew » Sat Jan 20, 2018 12:11 pm

Capacitance is part of it, the major part, but how do you know the figures you are given are correct or applicable. If you buy a RG cable from a reputable source like Farnell you should get good low cap BUT it is more to do with how you use it. The capacitance in a single cable is pointless as you use two and it is the interaction that creates far more problems. Non understanding eeeediots tie the two cable together or twist them, proximity creates capacitance.

Years a go I published a list of suitable cable, as I was asked. YET I still got amp failures I suspected were cable related, so a few years ago I just gave up on people telling the truth with specs and said "no other speaker cables than NVA ones should be used with NVA amp, any thing else voids our Warranty" result less failure. So I will recommend no other cables than NVA if you want low cap, plus the many other things in the design that cause them to extract far more music, as member here will tell you. I also refuse to give a cap figure as then I am held to ransom for an opinion which in reality may not apply due to other circumstances.

You have decided to take this course, it is about work and listening, Stu is doing well and learning. I have been learning for over 40 years and I still am.

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Re: AVI Lab Series Modifications (less is more)

Unread post by Dr Bunsen Honeydew » Sat Jan 20, 2018 12:20 pm

I refuse to get involved in stupid arguments about what constitutes safety, because it is pointless. If you bought hi-fi in the 60's no one gave shit if it had Cadmium, or didn't have safety regs, we just got on with it, very much under buyer beware, your safety is your responsibility, exampled by some people jumping out of planes with a what in reality constitutes a cloth umbrella - it is up to them. BUT we now have legislation, we have to conform to be legal, that is the ONLY thing that matters.

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Re: AVI Lab Series Modifications (less is more)

Unread post by _D_S_J_R_ » Sat Jan 20, 2018 12:26 pm

ABallagh wrote:
Sat Jan 20, 2018 2:10 am
And what's wrong with the bloody forum, not one single email to let me know someone is trashing my gear......grrrr
I was sorely tempted as these amps are still worth a good few hundred quid on the used market, but it's your property to do with as you please, so who the feck am I to have a go about what you've done?

The LDR preamps I've read about have massively complex control circuitry as ideally you need two per channel I think and the tracking of any pair is abysmal as they're cycled up and down. I honestly believe that a simple film pot is better (less is more, right?) but there are power amps out there that do need a line buffer to drive them for best sonics and minimal hum. NVA is NOT one of these and they're incredibly quiet with passive pre flat out.
...I have renounced the worldly bustle and live in peace at a quiet place,
I live alone in this my heaven, in my love (and) in my songs.

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Re: AVI Lab Series Modifications (less is more)

Unread post by Dr Bunsen Honeydew » Sat Jan 20, 2018 12:30 pm

Regarding suitable amps, the less complicated in the first place the better, with a known upgrade path so you are not on your own. Transistors, you can't do much better than get Les W kits and boards as Stu has, they are robust and reliable, if a little tooooo Naim for my liking. Valves, talk to Steve the Shadow and Lurcher, members here or join Audio Talk forum.

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ABallagh
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Re: AVI Lab Series Modifications (less is more)

Unread post by ABallagh » Sat Jan 20, 2018 2:10 pm

Dr Bunsen Honeydew wrote:
Sat Jan 20, 2018 12:11 pm
Capacitance is part of it, the major part, but how do you know the figures you are given are correct or applicable. If you buy a RG cable from a reputable source like Farnell you should get good low cap BUT it is more to do with how you use it. The capacitance in a single cable is pointless as you use two and it is the interaction that creates far more problems. Non understanding eeeediots tie the two cable together or twist them, proximity creates capacitance.

Years a go I published a list of suitable cable, as I was asked. YET I still got amp failures I suspected were cable related, so a few years ago I just gave up on people telling the truth with specs and said "no other speaker cables than NVA ones should be used with NVA amp, any thing else voids our Warranty" result less failure. So I will recommend no other cables than NVA if you want low cap, plus the many other things in the design that cause them to extract far more music, as member here will tell you. I also refuse to give a cap figure as then I am held to ransom for an opinion which in reality may not apply due to other circumstances.

You have decided to take this course, it is about work and listening, Stu is doing well and learning. I have been learning for over 40 years and I still am.
i was just looking for the value you published on another thread, the spec i posted of 17pfm is for a qed speaker cable, nothing flash, £3.85mtr. You would think the figure was for the finished product rather than just the wires, I was thinking if the value is good then i would pull the cable apart as per NVA principles.

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Dr Bunsen Honeydew
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Re: AVI Lab Series Modifications (less is more)

Unread post by Dr Bunsen Honeydew » Sat Jan 20, 2018 2:17 pm

I don't give a figure so I don't know what you are talking about, if I did it would be very broad benchmark.

Again I just waste my time, why do you think anything QED say is right, they largely talk marketing crap to get sales just like the others. EVERY QED cable I have ever tried sounds crap and a couple were seriously dangerous for NVA amps, yet all because of bullshit marketing men who run the company say they are good for everything.

Reality is not what this industry is currently about, believe none of them, unless you are dealing with a designer or maker, ignore their feckin' lying marketing depts.

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karatestu
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Re: AVI Lab Series Modifications (less is more)

Unread post by karatestu » Sat Jan 20, 2018 2:30 pm

Dr Bunsen Honeydew wrote:
Sat Jan 20, 2018 12:30 pm
Regarding suitable amps, the less complicated in the first place the better, with a known upgrade path so you are not on your own. Transistors, you can't do much better than get Les W kits and boards as Stu has, they are robust and reliable, if a little tooooo Naim for my liking. Valves, talk to Steve the Shadow and Lurcher, members here or join Audio Talk forum.
Les' new power amp boards are very un-naim :dance: They have a complimentary output stage rather than the quasi complimentary of the old RCA circuit. It loses the baxandall diode which is said by many (including Les) to be the source of much of the Naim PA sound. Still have input and output filters though :(

Les' active preamp module (821A) is the most simple of affairs with only 3x gain and very few components. It is a single ended transconductance design. Sounds very very nice.

Stu
Naim, Linn & Harbeth fanboy

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Dr Bunsen Honeydew
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Re: AVI Lab Series Modifications (less is more)

Unread post by Dr Bunsen Honeydew » Sat Jan 20, 2018 3:41 pm

The other alternative is Colin Wonfor (posts here), he does kits, real Class A ones as well. Hilarious high powered giant ones even that could probably heat a whole house. Colin know his stuff, hates marketing men and bullshit like I do.

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