AVI Lab Series Modifications (less is more)

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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 5:21 pm

_D_S_J_R_ wrote:
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.
They are indeed, I paid £450 i think, (its not the most expensive thing people are modding) I choose it for remote control, high current output and a review that said it was the best amp upto 3k. Yes we can ignore the review part but theres no doubt its really well made.
I dont know what constitutes "massively complex" it fits in the palm of my hand, i suppose it is compared to a pot though. Image
Theres also no evidence of abysmal tracking on these, as I said, its not another lightspeed clone.

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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 5:38 pm

AGAIN - you miss the point IT IS ILLEGAL, are you here as a shill for them????

I will not have illegal products promoted here, it makes me liable. You have had your say about it, any more promotion will be removed, and about any other LDR or other illegal products

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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 5:57 pm

Dr Bunsen Honeydew wrote:
Sat Jan 20, 2018 5:38 pm
AGAIN - you miss the point IT IS ILLEGAL, are you here as a shill for them????

I will not have illegal products promoted here, it makes me liable. You have had your say about it, any more promotion will be removed, and about any other LDR or other illegal products
NO PROBLEM, I am neither promoting or shilling for them!!!!! What would be the point, there has been no response from him since March last year, Im pretty sure he has sadly either passed away or is not interesting in selling anything. I was merely responding to incorrect assessment of my particular unit, but I will speak of it no more.

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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 6:00 pm

Dr Bunsen Honeydew wrote:
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.
Thanks I will have a look at these.

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Re: AVI Lab Series Modifications (less is more)

Unread post by Geoff.R.G » Sat Jan 20, 2018 6:05 pm

There are LDRs that do not contain Cadmium Sulphide but I know nothing about them. However one such is Lead Sulphide, which is not exactly healthy either. CdS sensors were used in light meters until silicon photo-diodes took over.

Looking for more information I found the following:
"Most of the cadmium that enters your body goes to your kidney and liver and can remain there for many years. A small portion of the cadmium that enters your body leaves slowly in urine and faeces.

Your body can change most cadmium to a form that is not harmful, but too much cadmium can overload the ability of your liver and kidney to change the cadmium to a harmless form."

Most importantly I discovered that damage caused by Cadmium is irreversible!

Acceptable exposure levels are minuscule. You can read all about it here https://www.atsdr.cdc.gov/phs/phs.asp?id=46&tid=15

This might enlighten some as to why these things are illegal in Europe, best advice? Take the circuit boards to a specialist recycling centre for safe, legal disposal.

Colin Wonfor
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Re: AVI Lab Series Modifications (less is more)

Unread post by Colin Wonfor » Tue Jan 23, 2018 11:28 am

There Photo sensitive FETs which are linear and not containing nasty stuff, some are made by this company.


Nais (Matsushita Electric Works) and there do them in isopaks under solid state relays
The other common name for this company is https://na.industrial.panasonic.com/
Fight back again and again. :evil:

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

Unread post by ABallagh » Wed Jan 24, 2018 7:46 pm

Colin Wonfor wrote:
Tue Jan 23, 2018 11:28 am
There Photo sensitive FETs which are linear and not containing nasty stuff, some are made by this company.


Nais (Matsushita Electric Works) and there do them in isopaks under solid state relays
The other common name for this company is https://na.industrial.panasonic.com/
Thanks Colin, have you tried them as a volume control?

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

Unread post by karatestu » Thu Jan 25, 2018 6:14 pm

When are you firing this up Alan ?

I have not yet got round to trying my amps without the input coupling cap, output zobel and inductor. I will remove one at a time and then listen. Input DC blocker will be the first to go as I am sure nothing nasty will happen - my pre has a DC blocking cap on it's output. The zobel will be next after that as I can just disconnect the wire which goes back to the psu 0V. Inductor will be last as I will try and solder a wire in just before it - my amp boards may get sold on at some point and the less component removal I do the better.

Regards, 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 » Thu Jan 25, 2018 6:26 pm

I am bored, can we have some more speaker fun please Stu, especially if it involves chainsaws. How about speakers made from hollowed out Oak trunk sections.

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

Unread post by karatestu » Thu Jan 25, 2018 9:24 pm

Been a bit busy Doc. Farming plus loads of bloody trees to chop down. My log store is gonna burst :shock:

i will have some large sections of Norway Spruce (Christmas tree to you lot) that would make speakers. I would have to bore in with the chainsaw from the top to hollow it out and then attach a top (or bottom). Then cut out the driver holes after making the front square and flat for the tweeter. Semi omni of course :dance:

I think i could do it but worry about the wood moving too much and splitting in a warm house. :think: :think: :think:
Naim, Linn & Harbeth fanboy

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