audio-talk

couple of points...the James are multi tap so will doubtless suit a setup your playing with.

As Nick says there is no competition, but if it's something to fiddle with then I strongly suggest you build a mofo...I'm sure that will give you something to think about. It will let you turn the wick up a bit more and will be operating in a happy area, just right for your listening space and speakers. As Mike Holmes would say, guess how I know.

ed wrote: ↑Wed Jan 05, 2022 7:00 pm ...but if it's something to fiddle with then I strongly suggest you build a mofo...I'm sure that will give you something to think about. It will let you turn the wick up a bit more and will be operating in a happy area, just right for your listening space and speakers. As Mike Holmes would say, guess how I know.

Cheers Ed,
I'll have a look at the relevant stuff on the Nelson Pass forum on DIYAudio. That'll make three amps, which would be a record in my house.

I think ive got a pair of jlh boards wot our phil (i think) passed on to me and some psu boards that i think came from ray if you want those to build?
That'd be four

Steve, I can supply you a pair of the MoFo circuit boards if you want.

And, the microwave oven transformers I got from Ray seem up to the job.

Thanks chaps, I'll think about it and PM when I make my mind up.

Cressy Snr wrote: ↑Wed Jan 05, 2022 7:15 pm
That'll make three amps, which would be a record in my house.

Only 3..

To add to the positives and thoughts already shared, I too really like your 45 amp, a lovely and sweet sounding amp to me.

I have a couple of pairs of sowters, as you know, and they are doing nothing if you want something to play with.
As Ed says the mofo is always worth a build, but you've heard mine a couple of times now, so you know what they are about.
But they are still little bit of an investment if your starting from scratch.

steve s wrote: ↑Wed Jan 05, 2022 8:12 pm
But they are still little bit of an investment if your starting from scratch.

Can be, price up the two heatsinks and chokes before starting.

Sorry, a little late to the party...

If a MoFo is of interest I have a couple of almost fullyy populated PCBs you can have for the cost of the postage Steve.

As a variation, how about a power FET device instead of the MosFet of the MoFo?

The LuFo uses the LU1014D device. The original version was around 39W output using a MosFet Cascode but with the power requirements of your speakers you could probably get away with a LuFo-Lite, which was a variant for headphones but capable of delivering a handful of Watts into 8ohms. It's as simple as MoFo but with the lower power you should be able to use smaller heatsinks and chokes = less cost.

https://www.diyaudio.com/community/thre ... mp.374760/

As you'll see on the link, the original power supply was a 19V computer SMPS brick, followed by a Cap multiplier. I can let you have a pair of the LU1014s and I have some PCBs for a cap Mx if that would help, though other power supply arrangements might be more your style.

One thing to remember is that MoFo (and LuFo) don't have voltage gain so you need to provide that upstream with your preamp.

Being slightly awkward, but also having gone around this loop myself...

Maybe, instead of building multiple valve amps because they do something that the NVA amp doesn't, but then realizing the NVA amp does something the valve amps don;t, so rinse and repeat. How about working out what it is the NVA amp doesn't do and see if a better SS amp would fix the problem. Then if you want a bit more 2nd and 3rd add a valve buffer when required.

Maybe start with this?

https://neurochrome.com/products/modulus-86

I heard one from a bunch of them some years back now and it was generally doing very little wrong.

Thanks chaps.
Contrary to what might be the unintended impression I’m giving. I don’t sit there agonising over perceived deficiencies in the quality of the sound that comes out of my speakers. I just find the whole hi-fi thing fascinating. I mean what is the absolute sound anyway?
I don’t believe it is possible to get every single aspect of what I want out of a system at the same time. It’s a hobby that keeps me occupied and it is rewarding in the sense that I like making objects. The feverish amp building of the past was more a physical manifestation of a poor state of mind than it was about anything to do with hi-fi. Trouble is, once it’s out there, it’s out there forever.
I don’t really feel that there is any need to make any more progress beyond what I have at the moment. Some may not understand that attitude, but what I’ve heard at Owston tells me that folks like a wide range of different presentations, some of which I like and others that I couldn’t live with if you paid me.
I’m near enough to what I like, that we are down to minor differences in flavour these days.

If I want solidity and authority, I use the NVA, intimacy and subtlety, I use the 45. A bit of both, a partial feedback SEP/SEUL.
It works for me because I have these options now, whereas before, when it was one amp and no backup, these options didn’t exist.

SS amp with valve buffer might be the way to go at some point. It is something I’ve thought about for years but have never got around to trying. The old WAD Pre II cathode follower type thing looks like a decent proposition. Silent power and heater supplies being a prerequisite of course.

On an aside, I was very aware of all (all I remember?) the bass sounding soft on many of the solid state powered bass drivers at our last owston meet.

What I mean by that was that the leading edges to bass notes sounded wooly and not real or accurate and the texture was missing from the bass

I put it down to cheap amps used to power the bass drivers, but I could be wrong on that assumption.

But it's still got me wondering why..

What it did prove is the mainstream thinking regarding bass powered by separate ss amps is flawed

The backing away from DIY stuff continues. The missus didn't think I meant it. She does, however, believe me now.

Having built the twin power supply NVA clone courtesy of Richard's boards a few years ago, I'd also built my Phono 1 into the amp, making it an old school fully functional integrated with phono capability.

Yesterday I was listening to vinyl, via the valve amp and Fane full-rangers when the left channel disappeared. After much cursing, plugging, re-plugging and a process of elimination, the fault was traced to the MoFi StudioPhono itself, which had failed on one channel.
Going inside the thing revealed a board, stuffed with surface mount components. Even the op-amps were surface mount devices, so that was that with regard to repairing the thing.

Back to the NVA clone and despite attenuating the input and, playing with the feedback, the damned thing was still too loud for my 100dB efficient Fanes, but it was the only way now that I was going to be able play any records. I'm not exactly rolling in phono stages.

To cut a long story short, I got pissed off with the racket, so decided to look for a pair of speakers more suited to the characteristics of the NVA. Like it or not, the NVA amp is not really a match for big, hi-efficiency speakers. Even Richard acknowledged that.

The Fanes go so loud on a whiff of throttle, that the NVA never really gets to warm up. I've never got the heatsinks above stone cold with the Fanes, which to me must be preventing the amp from giving its best performance, given the fact that Richard always emphasised the importance of a warmed through amplifier.

Anyhow, our Ant came up with a pair of little 1996 vintage Mission 731i speakers that had been stored for ten years at his place. He'd completely forgotten how he had acquired them and they were frankly in a filthy state, but I took them off his hands, brought them home and set about them with soft bristled brush for the bass driver and a tin of Pledge for the case.

They cleaned up a treat and worked when plugged in, after a test for shorts across the input terminals gave the same DC resistance on each speaker. They were advertised as 89dB efficient but are actually around 86dB/W and the attenuated NVA had to be wound to 2 o'clock on the volume control for decent volume. The attenuators were removed, restoring the amp to original spec.

I must say, with the NVA driving them, they are brilliant little speakers, especially for nowt. I love them. So does the NVA.

The Fanes will be retired once I have made some stands for the Missions at the weekend.
Now the heatsinks get warm and the NVA clone sounds better than I have ever heard it. A good result all round I'd say. They won’t be at Owston. I know the opinion held by you lot about ‘boof boof boof’ pretend bass from little ported speakers.
You’ve been trying to get away from it for years, and here I am embracing it. What have I done?

Very interesting!

Cressy Snr wrote: ↑Thu Apr 14, 2022 6:43 pm They won’t be at Owston. I know the opinion held by you lot about ‘boof boof boof’ pretend bass from little ported speakers.
You’ve been trying to get away from it for years, and here I am embracing it. What have I done?

If you need any moral support, i may have one or two monitor speakers with Purifi drivers there - they will have a bit of Boofboof, so you won't feel out of place.

IslandPink wrote: ↑Thu Apr 14, 2022 11:11 pm If you need any moral support, i may have one or two monitor speakers with Purifi drivers there - they will have a bit of Boofboof, so you won't feel out of place.

Well in that case…I’ll think about it