OLT Power Amp????

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AshM750.
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OLT Power Amp????

Unread post by AshM750. »

Does anyone know this power amp? Looks like its got the same volume knob as NVA pre amp??????
http://www.ebay.co.uk/itm/OTL-Power-Amp ... 3d03dcd120

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Re: OLT Power Amp????

Unread post by _D_S_J_R_ »

Never heard of them, but that means nothing.

The volume knob can be got from Farnell UK and my old Croft preamp uses them too...

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Progmeister
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Re: OLT Power Amp????

Unread post by Progmeister »

I do rather like your avatar
AshM750. wrote:Does anyone know this power amp? Looks like its got the same volume knob as NVA pre amp??????
http://www.ebay.co.uk/itm/OTL-Power-Amp ... 3d03dcd120
People turn to poison quick as lager turns to piss,,,J.C. Clarke.

AshM750.
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Re: OLT Power Amp????

Unread post by AshM750. »

Cheers Progmeister, thats my missus ;) :lol:


I was hoping someone on here might know somthing about the amp, it looks interesting :think:

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Dr Bunsen Honeydew
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Re: OLT Power Amp????

Unread post by Dr Bunsen Honeydew »

I think the vc is a DIY addition.

AshM750.
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Re: OLT Power Amp????

Unread post by AshM750. »

Dr Bunsen Honeydew wrote:I think the vc is a DIY addition.
Me too, but who did it?

I have a Magnum MF-300 PA, not many people know about them but its a great Class A/B amp. Thats why this has got me thinking.

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Dr Bunsen Honeydew
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Re: OLT Power Amp????

Unread post by Dr Bunsen Honeydew »

OK I will bite, but you will be better off getting a reply from Colin he has far more experience of power fets than I have. By the look of it and the fact that this was designed for pro work means it is almost certainly a Hitachi application note product. There are many of them with similar character including Dave's HH one, only varying because of power supply design. Advantage, virtually indestructible, and powerful as if you over drive them they shut themselves down. The opposite to a bipolar amp which runs away (thermal runaway) if overdriven. Problems, high "on" resistance which means low level musical details at low volumes are lost and they sound different at different volume levels. Also bass is like from a different amp as phase is buggered by the early pos and the neg devices having different characteristics.

Much of this has been solved since those early days and FETs for hi-fi are now a better proposition as Colin will tell you. But I still see no advantage to change to using them.

AshM750.
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Re: OLT Power Amp????

Unread post by AshM750. »

I have to agree with you reference different sounds at different levels, they claim my Magnum (MOSFET) is class A upto 20w then after that is class B. It does sound better at lower volumes though. Comparing it to NVA (A40 Monos) it does have greater depth and a fuller sound but NVA has the upper edge on detail and timing. If i compare it to Naim (Nait 5i2) it has a more bouncy musical sound than the Magnum but lacks detail and power.

So are all Mosfet amps like this? I wish we could combine all these great pieces of equipment to gain the ultimate sound.

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Dr Bunsen Honeydew
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Re: OLT Power Amp????

Unread post by Dr Bunsen Honeydew »

You could say the same for wine or even women, there is no such thing as perfect. Nearest is nva :mrgreen: and my wife :grin:

AshM750.
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Re: OLT Power Amp????

Unread post by AshM750. »

Ha! Ha! I can vouch for NVA but not your wife as we have not met! :lol:

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