Building a DIY amp with NVA amplifier boards

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karatestu
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Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu »

Dr Bunsen Honeydew wrote: Wed Mar 14, 2018 5:15 pm
karatestu wrote: Wed Mar 14, 2018 5:02 pm I have been itching to turn the volume up for this Herbie Hancock CD but I bloody can't :angry-screaming:
Haven't you got a spare switch of some sort, then you got two positions.
Good idea, why didn't i think of that. I think i have a 2 pole, 6 way source selector switch somewhere. 6 positions will be awesome :lol:

Thing is i am enjoying the sound so much with no source selector or volume switch. It doesn't get any simpler or cleanerthan that - CDP , TIS, potentional divider and off to 4 mono amps. :dance: And these welwyn rc55y resistors sound fine to me. Got some dale and msfr ? In the parts bins too.
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karatestu
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Re: Building a DIY amp with NVA amplifier boards

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Currently listening to Cannonball Adderley - Walk tall (live). It's fecking marvellous :clap: The sound is so dynamic, clear and raw - just like a live performance of this nature should be. The band kicks in after the speech at the beginning with all their might and all exactly in time like a good band ought to. The brass is ringing out as clear as a bell. Dynamics are like being there (almost) - when going in to a different section they suddenly give it more welly and this is all produced to me like I was on stage playing the drums. Bass is grumbling away in the background all the while.

I had a band rehearsal last night and it really reminds you of how good nva product and ideas are. No sitting on and squashing the music. After a 6 year break from being in bands (kids) i am now in two :guiness; all because my sound system since joining this forum has reminded me what real music sounds like and how glorious it is to hear (and play).
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SteveTheShadow
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Re: Building a DIY amp with NVA amplifier boards

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Aye...
Same thing has happened with my system. It seems to be giving off real music vibes.
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karatestu
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Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu »

Hey Steve, thanks for dropping by. So are you biamping your speakers now ? A20 & diy nva amp ?
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SteveTheShadow
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Re: Building a DIY amp with NVA amplifier boards

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Not yet, but you never know.
Somebody’s telling me the latest scandals.
Somebody’s stepping on my plastic sandals. Joe Jackson (1979)

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karatestu
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Re: Building a DIY amp with NVA amplifier boards

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Been a bit busy. Have a look now :dance: :dance: :dance:

Image

Added another psu for the front end. EI transformers and some more Avondale cap banks. All wired in with the tinned 2mm solid copper wire. I knew the psu was good to go as it was in use a couple of weeks ago. The relevant wire link was cut and the ends bent apart to separate front & back ends.

Image

Turned it on with the variac again. Nothing blew up, no magic smoke :guiness; Just checked DC offset and I think this is good to plumb in to the system. :grin:

More later when I am playing music..............
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karatestu
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Re: Building a DIY amp with NVA amplifier boards

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Playing Blue Note compilation Blue Funk and all sounds good to me :dance:

DC offset as it should be. Gonna play some tunes for an hour or two.
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Re: Building a DIY amp with NVA amplifier boards

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I put the EI transformer on the front end as they were easily available from another amp and I figured the lower amount of mains hash coming through would benefit the front end but not so much the output stage. Anyway I think the toroid with its lower impedance is better suited to supplying the higher demands of the output stage.

I'm not saying that the EI would be better on the front end than a toroid but I wont know that for myself until I have tried both. Anyway, now that I have the front & back split I can use my big 340VA toroids on the output stage at some point. The smaller 200VA ones I have in now could move to front end duties.

Still got my own rectifier & cap bits to build to replace the Avondale parts I have in now. There are other things to try as well but that's for another day/week.

I am trying to get a grip of what I am hearing now after this latest change. Need to play more discs. :grin:
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karatestu
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Re: Building a DIY amp with NVA amplifier boards

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Fecking hell. I have come to the conclusion that this amp is now on steroids or something. Dynamics, detail, atmosphere, sound stage all improved. A bigger improvement than adding a psu to my Avondale amps. I am over the moon with this. Just heard some very low level talking at the beginning of Bob Marley No woman no cry that I have never ever heard before.

Recorded music now sounds more like it is live, without the compression that many recordings have. Dynamics to die for.

:clap: :clap: :clap: :dance: :dance: :dance: :guiness; :guiness; :guiness; :grin: :grin: :grin:
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Dr Bunsen Honeydew
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Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew »

You have basically made the same change as A70 to A80.

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