Apologies to Roger Waters

[Greg.]

‘Is there anybody out there?’

Has lockdown apathy set in for all of us and we have nothing to discuss here?

Well, here’s a bit of stuff from me. I set about the rebuild of my WAD 2A3 PSE power amp a while back (I started a thread on it) and got all the hardware installed including a new updated choke, but when it came to all the wiring hook up, I lost the enthusiasm and the amp has sat unattended on the workbench ever since. I expect this is because I have a sound system currently in use that I am very happy with and actually have no real need to pursue anything else. This reminds me that there is no better incentive to get on with your building than what you are working on being an essential component to ensure you have sounds to listen to. I remember those days very well, even to getting up early to get the soldering iron active as my proper work started later at 2pm. That’s shift work for you.
Anyway, I have a new incentive to get the 2A3 finished albeit this incentive has been there all along and I’ve only just realised it.

My amplification these days is a Devialet 250 Expert Pro Core Infinity. This is basically a computerised integrated amplifier which includes a Streamer and a DAC. I don’t need the use of my 2A3 PSE power amp, but I feel that occasionally, it would be fun to use it. The Devialet is highly versatile and can be configured in all sorts of ways to meet almost any demand. This includes input RCA’s being reconfigured to become Pre out RCA’s. So, the plan is to get the 2A3 finished and use the Devialet as a Pre-amp incorporating the integrated DAC with streaming capability. All very do-able. I had been holding back on the 2A3 PSE for another reason. All the upheaval of swapping out one amplify to accommodate another with it’s need for a pre-amp section (I have my modified WAD Pre II units) which is a major exchange of kit, not to mention all the cabling
The idea of moving to Devialet was to minimise items of kit and simplify everything. Hooking up the 2A3 through the Devialet (input impedance can be digitally adjusted) will involve little domestic disruption and occasional use will keep my valve hunger at bay.

However, I now have grandchildren and we have just given my 9 year old grandson his first Scalextric. This meant getting all the old stuff out of the loft, including my original stuff from the 60’s and my later Son’s stuff, so I’ve been cleaning and adjusting anything still usable that can be incorporated into his set up.
I now have a box of about eight vehicles in various states of dis-assembly that all need a total rebuild. If I am lucky, I hope to salvage parts to get three old cars serviceable. It can all be done (a quality of Scalextric upgradability which is commendable) so for now, once again, 2A3 PSE is relegated to the back burner and Scalextric is the focus.

Finally, one other project of interest. My friend, Scott Lindgren, who has helped with WAD KLS3 modifications (see forum threads) has come up with an Impedance and Phase correcting filter for the KLS3 Mk3 Millennium. It sits after the amp and before the crossover. I ordered the components on 27th December last year and they have just arrived. Not bad considering Brexit constrictions with several parts of my order list coming from the EU, made to order. Another thing to build, fit and assess. All good stuff. I’ll let you know how I get on.

Ok, that’s me. Returning to ‘Is there anybody out there?’, come on, what are you doing?

[bob orbell]

Upgrading my Specialized Levo E-Bike and Janet's new E-Bike and riding as much as possible, even Janet managed 25 miles two days ago, on the music front, I have no need or intention of changing anything, all is working good, I spend more time listening to my new Stax L700 Mk II than speakers, subline, well, back to the bikes. And wot a blow about Sir Tom, RIP Tom. Bob

[petercom]

Amongst a load of, what I would call 'commercial' speakers for the various brands I'm working with, I am designing a pair of 'retro' speakers for Mission. Can't give specifics, yet, so don't pry!

What I can say is that it is a lot of fun buying older speaker designs and pulling them apart to see what made them tick. It's pretty obvious that us speaker designers were floundering around in the '70s through the '90s, trying to figure out how to match what we were hearing to what we were measuring. Simplicity was the key, on the basis that it's easier to modify a few components and hear the results rather than try and juggle with multiple components and end up more confused than when you started.

Today's software tools are an amazing help and I've improved the iteration between computer prediction and listening to the point where I can, say, design an acoustic 4th order Linkwitz-Riley crossover and then tinker with it until it sounds right. Wharfedale Elysian is a good example.

But hats off to the designers in the '70s who, I've heard tell, went into the anechoic chamber with a bucket of components and equalised everything the best they could. And to those who, like myself in the early Heybrook days, spent hundreds of hours doing it just by listening!

[Greg.]

Originally Posted by petercom

Simplicity was the key, on the basis that it's easier to modify a few components and hear the results rather than try and juggle with multiple components and end up more confused than when you started.

Good to hear from you, Peter. I hope all is well with you.

If the above quote is a subtle way of telling me I may be making things too complicated with my KLS3’s, yes, you may well be right. For me, the ‘Phase and Impedance correction filter’ is very much an experiment and it’s being done on a breadboard basis. My speakers are currently exactly as you modified Guy Pettigrew’s pair and just how you wrote it up in HFW, apart from me extending the length of the baffle mounted twin ports which in my room, lowered port resonance so it is only troubling at very very low frequencies (think action film sound track).

Certainly I have been very satisfied with the result. There is another first class DIY speaker that sounds very similar to the KLS3’s. Scott designed a phase and impedance filter for these with a positive outcome on sound improvement. For that reason alone, I am trying it out on my KLS3’s as an experiment. I will report back here the conclusion of that experiment.

[Greg.]

Originally Posted by bob orbell

Upgrading my Specialized Levo E-Bike and Janet's new E-Bike and riding as much as possible, even Janet managed 25 miles two days ago,

I’d be interested in what upgrades you have done. A while back I read up on electrification kits that could be used to modify a standard bike. All very interesting and quite a tempting proposition.

[Baggy Trousers]

Originally Posted by petercom

But hats off to the designers in the '70s who, I've heard tell, went into the anechoic chamber with a bucket of components and equalised everything the best they could. And to those who, like myself in the early Heybrook days, spent hundreds of hours doing it just by listening!

Perhaps the titfers should be raised even higher for those of the '50s who in the absence of anechoic chambers (although they did exist), computerised prediction equipment and all the sophisticated gizmometry currently available, managed to create perfection with nothing more than inspired intuition. Don't believe me?

If you can find one, listen to the brilliant Ronald Rackham's Tannoy Autograph.

Peter - nice to know you're still about!

[John Caswell]

Well what have I been up to,
Been in quarantine for a couple of non consecutive months as the ladywife has had two very successful cataract replacements. Shifting a 70kg amp around on the bench managed to put my left shoulder out of kilter for 3 weeks over the Xmas period.
Been suffering from sciatica type leg pains for about a year and after an osteopath visit plus two consultant visits and X-ray plus MRI scan, find I have spinal stenosis, fortunately exercise will help 'cos I did not fancy any spinal operations. My luck is it would go wrong! I suppose I should be a bit more careful as this year I tip over the big 80 - we shall see!
Work wise still fixing all sorts of things to pay for the luxuries in life. Very variable from big 200 Watt valve amps to even bigger 300 Watt SS amps.
Bought a very nice ex military R210 receiver which had been modified for a somewhat inelegant external mains PSU. So converted it back to the original vibrator driven unit (but an electronic "vibrator"). Knocked up an 24V regulated PSU for it and off we go!
After many years finally laid my hands on a very clean Dynatron T10A am/fm tuner so that is next in line for refurbishiment. Bought a Majority all band tuner for the workshop but only use it on internet radio.
Bought an HP1740A oscilloscope for spares/repairs as a spare for my main HP1740A, spent a little time stripping it apart for PCBs and "unobtainium" special HP ICs.
Modified my Revox B77 Mk2 for a LED display turns counter and also looking at adding externally a pair of BBC type PPM as I hate VU meters.
Bit of a general clean and tidy up of the workshop.
Changed to an electric car last March, as we only do about 4K mls per annum, a Peugeot e208, very impressed, got a "free" 7kW PodPoint home charger with it as part of the promotion. During the summer a range of about 190mls easily achieved (theoretical is 215mls) but the winter hammers this down to about 130/140mls pretty much as expected, but there are plenty of chargers of all types locally.
That's about it really, still try to keep a cynical jaundiced outlook in the world.
Highlight of the week was the Covid 19 jabs for the ladywife and I.

John

[petercom]

Originally Posted by Baggy Trousers

Perhaps the titfers should be raised even higher for those of the '50s who in the absence of anechoic chambers (although they did exist), computerised prediction equipment and all the sophisticated gizmometry currently available, managed to create perfection with nothing more than inspired intuition. Don't believe me?

If you can find one, listen to the brilliant Ronald Rackham's Tannoy Autograph.

Peter - nice to know you're still about!

Agree with you about the Tannoy Autograph and also want to drop in a mention for Gilbert Briggs who was doing sterling work at this time through the combination of measuring loudspeakers hoisted high off the ground plus extended listening sessions and tweaking at home (with the help of his daughter). The corner reflex, Airedale and SFB3 are well worth a listen.

[Phil Y]

Hello everyone,

I've not posted for quite a while as simply, I have done nothing to my hifi. Early last year (I think) I got quite enthusiastic about taking the jump to moving coil and after researching the options, both cartridges and transformers, l was getting close to making a move.
Then one evening, I was listening and It suddenly struck me, I was really enjoying it and was actually very happy with how things were sounding. I was only really looking at upgrading because I thought I should, because it was the next logical step so to speak. I'm not saying I will never upgrade but it is for now at least, on the back burner and I will continue to enjoy my modest Goldring 1022gx.
My power amp, Kat88 has in the last few weeks started making intermittent rustling noises on one channel so that will need looking at, but it is not bad enough to pull things apart yet!

In other news, late last year I bought an electric guitar and have been using my weekends to build an amp for it. I based it on an early 60s Vox circuit. The first attempt worked but the mains transformer started to drip wax the first time I left it on for an extended period so another search in the back of the garage revealed a chunkier one. Unfortunately this one is lower voltage which meant rebuilding the PSU with solid state diodes and a downgrade to 10 watts rather than the intended 15w. This seems to be OK now so I'm about to start on a box for it, then after that will be a speaker cab to go with it.

Phil.

[bob orbell]

Arr Phil, once you get into MC there will be no going back, I tried twice after trashing an Ortofon MC30 and later an Ortofon Kontropunct, I now use a Ortofon Cadenza Bronze, very good, so neutral and very detailed with no harshness, of course, the down side is price, but its only money , as for your KT88, try pulling all valves and refitting, it may just be dirt on the pins, if that does not work, keep an eye on the power valves, if one starts to glow red, switch off and investigate before it goes bang. Bob