Another DIY SS Amplifier with NVA Boards

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SteveTheShadow
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by SteveTheShadow » Wed Jul 11, 2018 3:44 pm

savvypaul wrote:
Wed Jul 11, 2018 1:17 pm
Would love to hear that set up...
Hi Paul,
If you are ever in South Yorkshire you are welcome to come and have a listen.
I was talking to Richard at Owston and he suggested LS6 speaker cable and SSC interconnects as a possible upgrade path, although the basic system really is excellent now. I can't complain about anything. It does music.

The speakers themselves have been angled slightly away from axis in a toed-out arrangement, known in pro circles as a "splayed array" This ensures that listeners can never be on axis to the drivers as they have a rising frequency response. It works beautifully.

I kept vacillating between my 2W single ended valve amp and the NVA DIY, but overall, the NVA is just so good, it has taken up permanent residence in the system now. I don't know what I've done, I don't know much about transistors, but putting a second LED on the negative rail, has done something very positive to the music. What the mechanism is I'm not sure; might have something to do with having both rails now standing on the 1.2V drop of an LED each, rather than only the one.

If that's the case, then not having an LED at all might be even better, but we are now getting into tiny differences. Jimmy Hughes used to prattle on in the '80s, about the sonic benefits of disabling the indicator LEDs on his preamp, triple Krell power amps and in the on/off button on his LP12. Maybe he was talking :Bllocks: and maybe I'm talking :Bllocks: too :lol:
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

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savvypaul
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by savvypaul » Wed Jul 11, 2018 4:06 pm

Cool.

I'm going to pop down at some time to see Anthony about making me an idler deck. Maybe we can combine?

...I can bring some LS6, SSP Mk2 and TIS with me...
"The one who would whistle to Throbbing Gristle through harsh times in Umberstone Covert."

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SteveTheShadow
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by SteveTheShadow » Wed Jul 11, 2018 4:11 pm

That'll do nicely :)
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

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karatestu
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by karatestu » Wed Jul 11, 2018 4:54 pm

I don't bother with LED's in anything diy. Always thought it was added complexity and can never be bothered.
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Lurcher300b
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Lurcher300b » Wed Jul 11, 2018 5:41 pm

Why not just have a single led with a double sized resistor between the +ve and -ve lines?

SteveTheShadow
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by SteveTheShadow » Wed Jul 11, 2018 5:50 pm

Never thought of that Nick.
I'm not used to bipolar power supplies as you can no doubt tell. :oops:
Got two holes in the front panel now.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

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Firebug1
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Firebug1 » Wed Jul 11, 2018 8:17 pm

SteveTheShadow wrote:
Wed Jul 11, 2018 5:50 pm
Never thought of that Nick.
I'm not used to bipolar power supplies as you can no doubt tell. :oops:
Got two holes in the front panel now.
It now has eyes, just draw a big smile below :grin:
Rega\Teac\NVA\SA Mantra30\ATH-A900X
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Dr Bunsen Honeydew
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Dr Bunsen Honeydew » Thu Jul 12, 2018 10:07 am

Customers want a LED, it is helpful to know the amp is on. But I can assure you I know of the slight negative effect of them to the music, and I mean slight. To the point that with the smaller end of the amp range it is really not worth bothering about. The other thing that slightly messes up the performance is the mains switch and over time this can worsen if used a lot due to slight arcing on contacts. This only effects the bigger amps with bigger power supplies hence bigger switch on surge. My decision was to leave the LED and switch on the standard Black Box Range up to A80s, and remove switch and LED now from the Statement / Bespoke amps. With the advent of the A100 which is really a mini TSS I have left them off that as well.

SteveTheShadow
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by SteveTheShadow » Sat Oct 13, 2018 5:03 pm

Inspired by Stu's renewed DIY efforts, I thought I might as well join in.
Not a spectacular bit of messing about, but I had originally had four power supply caps in a row behind the output transistors. This had been reduced to two, so I decided to put four back in.
The two resident caps were a pair of 80V, Supertech, slit-foil jobbies, giving 10,000uF per rail. So, in the vacant slots left after the twin rectifier PSU had been abandoned, I stuck a 6800uF 63V Samwaha, audio cap. So now we had 16,800uF per rail. That's 33,600uF in total.

Image

Switched it on and cued up some music and WTF? It didn't seem as 'loud' for the volume control setting on the preamp, as it had before the cap implant. So increasing the volume by one eighth of a turn, I continued. Now the gain could not have miraculously reduced, just because of an increase in PSU capacitance, so what was going on?

Well as soon as I sat back to listen seriously to what was coming out of the speakers, it became apparent that the soundstage had expanded significantly, not only widthways, but also in terms of depth. The presentation of the music was less forward than it had been with the 10,000uF supply and the sense of effortlessness had improved, from very good to, 'hmmm, that's interesting.' Instruments had further separated out from each other, so that it was easier to follow individual strands of a mix than it had been previously.

Now the bass instrumentation and where appropriate, kick-drum, provided a foundation to the music, that had gone from your standard concrete footings, to 3m steel piles set onto granite bedrock. In short, the bottom end was imperturbably solid, which actually comes in very handy with the high Q Fane drivers in sealed boxes I'm using. You want your amp to be in control of the cones of these speakers, whose magnets are not the largest you'll find on a 12" driver.

As a further result of this extra control, voices, both lead and backing, were held strongly and securely in space; away from the rest of what was musically going on, so that lyrics were easier to follow and backing harmonies became more of a piece. The way this amp treats voices is great; not a hint sqwawk, nasality or shriek. It was already very good in this respect, but now it's quite superb.

All in all, a good hour's worth of work I think :mrgreen:
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

Lurcher300b
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Lurcher300b » Sat Oct 13, 2018 5:21 pm

Can I make a small suggestion. Move the point the transformer secondary connect to the caps so the charging current doesn’t pass where the take off point for the amplifier is. Looking at the above photo, it just involves moving the transformer black and red wires to the other end of the bus they are connected to, directly onto the cap terminal.

Actually, the above photo confuses me, normally transformer secondary wiring are (black red) for one winding and (orange yellow) for the other, but yours seems different in that you have the yellow and orange connected together.

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