Building a DIY amp with NVA amplifier boards

A place for DIY project discussions.
Forum rules
1. No ad-hominem
2. No spamming or shilling
User avatar
Dr Bunsen Honeydew
Posts: 29243
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew » Sun Mar 11, 2018 2:23 pm

I am just like an old tabby pussy cat who is getting to the point he only wants to sleep in front of the fire on a comfortable chair, and get a belly rub and cuddle occasionally.

Stu entertains me, Steve is good bloke who deserves a really good hi-fi but is short of dosh. Just remember I am not doing this for money and try and find your own belly rub :mrgreen:
Image

User avatar
karatestu
Posts: 1291
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu » Tue Mar 13, 2018 2:38 pm

Further observations as these boards continue to get better. Plus I got rid of the active preamp.

I have noticed less sibilance on vocals, especially Stevie wonder which can be a bit hot at times. The sound is even more in the room now and the feeling of it being projected at you has decreased even more (the semi Omni approach the sound was not squirted at you to start with). Soundstage and imaging has improved.

I am not missing the artificial sheen over the music that has now gone since replacing the Avondale power amp boards and active pre. The nva boards just get out of the way. Dynamics are very good with this, better than the AP20. Stevie Wonder Innervisions that I am playing now is sounding better than I have ever heard it. Detail is there but it manages to pull off the trick of being extremely detailed, laid back (compared to other amps I have had), truthful yet never fatiguing or harsh.

Stevie's multi layered synths are playing together and I could almost imagine he is playing all the parts at once rather than layering them. His piano parts are exemplary and the performance has been elevated to a greater height. I am now imagining the hammers striking the wires rather than just a sound magically coming from inside the piano.

There has always been something that bugged me about my system and now since playing about with my amplifiers I have finally succeeded in eradicating it altogether. I always attributed the slight harshness, the sheen over the music to the CDP which I have extensively modified myself. Now I know I was looking at the wrong component.

I have played about a lot with psu's and regulators trying to extract more information from what ever component. Often there would be more detail as the noise floor dropped away further but it does not alter the fact that the circuit it is providing power to is ultimately not up to scratch. The result was more detail but often in an "in your face" kind of way. The NVA circuit is different. It is ultimately correct to start with as there are no fancy regulators, rectifier diodes, caps or transformers needed to get it to play music.

It makes me feel silly that for years I have been chasing around trying to improve the sq of my system and being completely on the wrong path. The path to music is now blindingly obvious. I do not care for the "hifi" aspects of the hobby any more and will gladly forget about them :grin:

My path is clear to me now. Add front end psu's, build a stepped attenuator, add more NVA based amplification , finish my speakers and fart about with turntables. Not necessarily in that order :dance: Oh, and get more NVA cable.
Naim, Linn & Harbeth fanboy

Lurcher300b
Posts: 626
Joined: Tue Jun 14, 2016 1:58 pm
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by Lurcher300b » Tue Mar 13, 2018 3:02 pm

Not wanting to remove praise from the amps (not having heard them), but I cant overstate the damage that just about every active preamp does. I have remarked before that designing preamp are hard, I don’t think people believe me when I say that. Generally unless you have amps with a stupidly low input impedance or a source with a stupidly high output impedance, if using a passive preamp doesn’t sound better than a active one, there is something else is wrong with the system.

User avatar
Dr Bunsen Honeydew
Posts: 29243
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew » Tue Mar 13, 2018 3:36 pm

Steve is not far from you near Doncaster. I wish I was nearer. All the interesting DIY stuff seems to be in Yorkshire.
Image

valvesRus
Posts: 96
Joined: Sat Feb 24, 2018 2:34 pm
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by valvesRus » Tue Mar 13, 2018 3:40 pm

Lurcher300b wrote:
Tue Mar 13, 2018 3:02 pm
Not wanting to remove praise from the amps (not having heard them), but I cant overstate the damage that just about every active preamp does. I have remarked before that designing preamp are hard, I don’t think people believe me when I say that. Generally unless you have amps with a stupidly low input impedance or a source with a stupidly high output impedance, if using a passive preamp doesn’t sound better than a active one, there is something else is wrong with the system.
I never realised you were a passive preamp fan. :o

Is a buffer after the passive pre good for "driving" long interconnects ?

User avatar
Dr Bunsen Honeydew
Posts: 29243
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew » Tue Mar 13, 2018 3:44 pm

It depends on the interconnect.
Image

Lurcher300b
Posts: 626
Joined: Tue Jun 14, 2016 1:58 pm
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by Lurcher300b » Tue Mar 13, 2018 4:09 pm

valvesRus wrote:
Tue Mar 13, 2018 3:40 pm

I never realised you were a passive preamp fan. :o

Is a buffer after the passive pre good for "driving" long interconnects ?
I am of the less is more mindset. I did make a active preamp once that I liked, but it was very costly and full of transformers. I prefer a simple pot or a tranformer/autoformer preamp. If you need a buffer, then use a buffer, a unity gain line driver is easy enough to make with a bit of care to the power supply side.

User avatar
karatestu
Posts: 1291
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu » Tue Mar 13, 2018 4:56 pm

Lurcher300b wrote:
Tue Mar 13, 2018 3:02 pm
Not wanting to remove praise from the amps (not having heard them), but I cant overstate the damage that just about every active preamp does. I have remarked before that designing preamp are hard, I don’t think people believe me when I say that. Generally unless you have amps with a stupidly low input impedance or a source with a stupidly high output impedance, if using a passive preamp doesn’t sound better than a active one, there is something else is wrong with the system.
Having made a one step attenuator :grin: I am finding out for myself that active preamps are the devil's work.

I started my sound system journey with Naim :roll: I joined the Naim forum about 2005, got to find out about PFM and joined there. Naim forum soon got forgotten about and I discovered that pfm had a diy room :dance: Read the whole room top to bottom from a position of knowing nothing about electronics at all. Most people there said that passive pre with Naim did not sound right. I believed them and never considered it again until last year. Went to visit Les W, mentioned a passive pre with his amps and he said I wouldn't like the result. So I did not bother.

Since joining here I have learned of two people using Avondale amps and passive pre with no problems. Alfi being one of them. I wish I had done it years ago now :( What an idiot I have been. I also like the fact that I have got rid of a psu as well - makes things simpler and less EMI about the place.

Now, I have read lots about the input stages (LTP & VAS) of power amps. Is it not that they are similar to an active preamp (voltage gain) and as such benefit from as good a power supply as you can give them (depending on PSSR). When you see some of the lengths that people go to regulate their active preamps it was not a surprise to me when I regulated the front end of my Avondale power amps on a dedicated psu and the performance improved greatly. But I did it all in one go and don't know how much the regulation improved it on its own.
Naim, Linn & Harbeth fanboy

User avatar
Dr Bunsen Honeydew
Posts: 29243
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew » Wed Mar 14, 2018 10:29 am

PFM is full of this shite, you could do them a favour and try and educate, are you still posting there.
Image

User avatar
karatestu
Posts: 1291
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu » Wed Mar 14, 2018 1:05 pm

Dr Bunsen Honeydew wrote:
Wed Mar 14, 2018 10:29 am
PFM is full of this shite, you could do them a favour and try and educate, are you still posting there.
Very occasionally.
Naim, Linn & Harbeth fanboy

Post Reply