[Greg Erskine]

Hi Hugh,

Just too let you know I just noticed a new advertiser in October's Silicon Chip.  

Regards

[AKSA]

Yes, Greg,

You got it......  I decided to try for the local rag for a time, see what happens, and soon I will be advertising in DIYaudio with a simple banner ad.

Thanks for confirming;  I hadn't seen it yet!

Cheers,

Hugh

[Greg Erskine]

Hugh,

It looks excellent and different enough to stand out.

I wouldn't let Leo Simpson (the editor) know you have valve gear, he had a massive dump on valve amps in his editoral (again).  

Regards

[Geoff-AU]

yeah, they were really cut when they had to publish their valve pre-amp kit

[AKSA]

Greg,

I saw Leo's last dump on tube amps, and came away perplexed.  Why would he do this, taking such a categoric stand in a highly subjective area?  I think he believes emphatically in the straight wire with gain, the math and measure approach, but he absolutely refuses to acknowledge that most amps designed according to this philosophy finish as a 'straight wire with grain'.

Very odd.  I try to avoid taking categoric stands, as someone is almost always out there lurking, ready to prove you wrong.  And being caught with egg on your face is not something I enjoy.  Reminds me of the English Professor who was lecturing his students:

'Although there are countless examples in the English language of double negatives meaning the affirmative, there are no examples whatever in the language of double positives meaning the negative'.

Heard quietly, almost offhandedly, from the rear of the lecture theatre:

'Yeah.  Right'.

Cheers,

Hugh

[Greg Erskine]

'Yeah. Right'.

I get it... hehehe.  

I often laugh at the people that have such a strong view on a topic and they actually believe everyone else is deluding themselves. Reminds me of that Latham chap.  

[Geoff-AU]

Yeah I think one of the important lessons in life is to realise that you could be wrong..  cutting that amount of arrogance out of everything you do makes life easier for you when proven wrong (because the hole you have dug is nowhere near as deep), and everyone else the rest of the time!!

I feel the same way about religion.  I'll find my own path, thanks.  Fanatics and institutions can all go to russia

[JohnR]

Why would he do this, taking such a categoric stand in a highly subjective area?

Well, the magazine *is* called _Silicon_ Chip

[Oz_Audio]

Hi Hugh, I'm still in the background and I cannot let this one go  

I have always been of the opinion that one must make strong stands on most things.  Its the only way to get good debate from those with knowledge and keeps the followers in check so they don't think for themselves and stuff something up.

I have also always let someone with good argument tell me that I am wrong and gracefully aknowledge that they are correct, if they can prove it.

It has always been I believe this, prove that I am wrong, and I will accept.  In most cases progress is made as long as ones ego lets them!

Maybe the editor of Silicon Chip is laying down a challenge??

Mark

[ginger]

Some of you boys (and girls) haven't been paying attention.

The Silicon Chip 12AX7 preamp project was a bit of a joke BUT they have in the last couple of months published an Valve Amp project (the MUDLARK).
Quite interesting too - Parafeed Parallel Single Ended Triode strapped 6L6 using a 6GW8 as pre/driver and using Flouro balasts (3 in series to give 9H) as anode choke loads with some clever power supply tricks using back to back toroidal power trannies. It been designed down to a price BUT very cleverly so that performance has'nt been compromised by much. A 20W per channel SE Triode Amp kit for less than $1000 Australian. I say "WELL DONE". Well, probably well done, I haven't actually listened to a MUDLARK (yet).
The traditional way to get 20W per channel from a Single Ended Triode is to use an 845 or 3 parallel 300Bs (or 4 or 5 parallel 2A3). For these arrangements the tubes alone would exceed the total, kit cost.

All this despite the editorial in one of their first issues which stated "We will never publish a valve amplifier design".

Hugh,
I would'nt be too concerned about competition. I know from personal experience exactly how difficult it is to get a valve amp sounding better (to me at least) than my AKSA55N+. While I claim to have done it on at least   one (maybe 2) occassions now, I spent more on transformers alone than the total cost of the AKSA. One of the reasons I thought going parafeed in the MUDLARK was a clever idea (as you would know, you can make better output transformers, cheaper, for parafeed than standard arrangements).

Cheers,
Ginger

[AKSA]

Mark,

Thanks for your comments;  yes, it's possible Simpson is laying down a challenge, but I don't think so.  He takes himself very seriously, and is not the type to feign an argument.  Interestingly, he's not a BSc or a BEng, he's a BEc.  (You might consider my quals too, I'm a BEd and a MBusIT, for Gawd's sake........ )

Ian,

I have that copy of Silicon Chip, and I agree emphatically that Whitby's design is outstanding, both in tech terms and from the POV of cost.  I have used the very same fluro ballast, the EC9, in some of my tube circuits, and I applaud the imaginative way he's cut costs.

His use of unconventional tubes, back to back toroids, parafeed, and a cleverly configured solid state emitter follower to drive the output grid into A2 is masterful, and illustrates both powerful abstractive ability and deep experience.  I like the design very much, and would like to chat with this guy.  Might invite him to one of my Sunday breakfasts, lots of old geysers doodling over lattes on napkins.......

You talk with authority of the AKSA N+, and I thank you for the nice comments.  How would you react if I suggested that a hybrid is possible which integrates a tube into an AKSA 100N+?  Would it have SET midrange and top end with bass slam and impact of the AKSA?  If this could be done - without transformers or chokes - would this interest you?

Cheers,

Hugh

[bluesky]

Hi Hugh et al,

I thought I would chime in on this one.  Thorsten Loesch wrote are really interesting article on Single ended triodes in which he states that the human ear canal somehow changes sound waves of particular frequencies or harmonics and does not register distortion. He quotes research done by some boffin a while ago which provided evidence of this.

Now I find this VERY interesting as the pure scientific measurements are only done on amp, not the human ear and how we perceive music that we hear.  If this is so, then Mr Simpson may well have a "big breakfast" all over his face.

The other thing is cable burn in, the objectivits say it is scientifically impossible and yet I read a recent posting on Audio Circle where recent research spoke of electron pathways through wire being established over a period of time.

For myself, I am going to build a cheap SET in the form of the Darling amp after hearing it at a friends place.  It will cost me less than $200 as I got most of the parts given to me by some generous people over time.  I really want to find out for myself what all the fuss is about.  

I have also learnt never to say never, science continues to have convention thrown upside down all too often and I think Mr Simpson would do well to think about this and at least say things like "from what I know to date......"

Cheers

Bluesky

[ginger]

Hugh,
Yes it would interest me - a lot. How close to reality is it? Do you need a first customer/Beta tester and how much?

I have "traditionally" taken the view that to have a tube amp it MUST have a tube power stage and an output transformer otherwise its "Just another hybrid" BUT then I've got plenty of tube amps, I only have the one SS Amp (well actually I have an old Auditech 033 Module 100W per channel Job from 1970 on a shelf somewhere which I'm not game to plug in and turn on anymore unless I start replacing the electrolytics). Another SS (or hybrid in this case) amp would'nt go astray.

I cycle through my amps, when this particular one sounds better than that particular one then I dive into the lesser of the two (or more) and make mods until things are reversed and start all over again - the usual audio nutters quickstep (or should that be Waltz). A "Satisfied Audio Enthusiast" I think is one of those self contradictory terms like "Military Intelligence" and "Microsoft Works".

No amp is ever "finished". Then I don't have to worry about commercial concerns and getting product out the door. At least I don't in my hobby work. In my Design Engineers DAY JOB I have a Requirements Specification, and that makes life very easy - the jobs DONE when the Requirements Spec is met. If I can do better and the customer wants it, well that costs more and is a contract extention.

I actually have the AKSA55N+ high on the list for another cut - I wanted to explore current sourced shunt regulating the front end diff amp supply.
This "scheme" takes any residual noise on the rail to virtually zero due to the attenuation afforded by the huge AC Impedance of the current source and the low AC impedance of the shunt reg. I recall that when we first fitted a Blackgate for C3 on the diff amp supply it made an huge difference, which I attrributed (at least in part) to the superior noise performance of the Blackgates. I want to try pushing that idea to the limits to see what (if anything) happens - if you don't try it, you'll never know. What I'm looking for is the last  percent or 2 of detail. Of-course I've mucked about in this area of the circuit before and ended up abandoning some "bright" ideas as being not so "bright" after listening to them.

I don't see any reason why an appropriate  tube front end, either for the diff amp stage (with or without a SS current source tail) or even the VAS stage (with or without a SS active load) or both could'nt achieve what I'm looking for. I trust your judgement - if you have something you think worth trying then I'm up for it. Send me a PM regards costs etc.

Light Entertainment this weekend - A local Metal Head / Shreader says his Marshall just ain't hacking it anymore so I have it to work on, probably just tubes BUT I'd best warn the neighbours.

Cheers,
Ian (Ginger)

Bluesky,
Do experiment with the darling - just be aware its what we call a "Flea" Power Amp. If your speakers are'nt at least 93dB/W/m you won't get decent listening level out of until its pushed into distortion. I have a 20W per Channel 845 SET which is nice to listen to occassionally. After a while, especially at higher levels it just becomes abit of a second harmonic generator and I get bored with it, just too coloured.  Also I personally find SETs subjectively slow with little impact or slam. I'm mostly mucking about with Push Pull Triode amps at the moment.

[bluesky]

Hi Ginger

Yes I am all too aware of the low power rating of the Darling amp so...........I am going to  build a "Double Darling" which will bring it up to a massive 1.5 watts!

However, I recently received a small windfall and went beserk buying audio stuff.  The first was the plus kit for my 55 watt Nirvana.  Then I bought two pair of Coral Flat 6's with Coral horn tweters, and then.........I came across a pair of Coral Beta 8's that were brand new and frequency matched.  So much for my small windfall!

The Coral Flat 6's when paired should reach 98dB sensitivity and the Beta 8's are some of the last that were made and are rated at 101dB.  this should enable me to use the Double Darling amp well within its limits before distortion rears its ugly head particularly at low listening levels.

It is my intention to also make the Aksa a 25 watt version, should I find the Corals to be "my cup of tea".

If not, oh well, I will have learn a lot along the way, and that is always worthwhile!

Cheers

Bluesky

[ginger]

Bluesky,
Any progress on your Double Darling. Despite what i said in the earlier post about "Flea Power" Amps I and others continue to be amazed at the sound quality and level that can be achieved with just 1.5 Watts. A few months ago I sent Hugh a spare 6EM7 I had on the shelf for a spare for a similar amp he built and I believe was very happy with.

I just finished a restoration on a bakelite case Mullard valve radio with a single ended 6V6 cranking out maybe 1.5 to 2 Watts into an ancient 8" speaker . I don't claim its HIFI but it truely is gorgeous.

For a Clock Radio I use an electronic mains timer/switch to turn on an old Philips FM Tuner, feeding a Rogers Cadet III (8 Watt per Channel from push pull 6GW8s) hooked to a pair of vintage Warfdales. That ain't exactly HiFi either but would never go back to one of those modern store bought $50 jobs designed to fit on the bedside table.

The Darling will probably not cut it as your main HiFi Amp (thats what the AKSA is for - right) but will be ideal for Study/Bedroom/Kitchen/Workshop.
I've been tempted to build one myself - maybe when I finish the current project 120W 4 x KT88 Monoblocks and my next project - another cut at the 55N+ (To add another plus I hope).

Cheers,
Ginger