headinclouds

I've just looked up his audio grade description: In audio grade, noiseless transformer price You'll get transformer wound on high inductive, selected and measured core. Core and all the windings will be impregnated. Transformer will also has electric and electromagnetic shields, epoxy filled interior and mounting pads in price. Shipping cost to UK - 19,00 EUR/package up to 30kg. (1pc 100VA's = 1,4kg) Payment via bank transfer or PayPal. Production and delivery in ~18-24 days .

About 3 weeks to arrival in UK from Poland, obviously probably longer to your destination Cheers

Yes I didn't give any spec details just a heads up on a supplier who seems OK. I specified 300mm leads.

on the subject of transformers I and several others have had good service from Toroidy Poland. I contacted him because he was recommended on a diy audio forum. I've used three of his and they all work as intended, although only been in service for a few months so far. They are also quiet in operation. Contact Tomasz Lachowski [email protected] Anyone else experience with them? To answer SoupRKnowva's question; I defer to more experienced members, but I'd say the PS is not the problem as far as running out of steam. The max bias current I would use is around 10mA as the transistor is reaching its power limit. ......... You could find something like an IC socket but I would just solder pins or short length of stiff wire in place and solder the resistors on temporary. Not much less than 100ohm though. There are comments ealier on about calculating the bias. and also the extra drift that comes with the higher bias.

I like that simple case Wachara. Could you say why three sockets and do they have same bias or different?

Excellent! Those kompact boards look good and with the mini PS the on-board version will fit a smaller case.(if a suitable one can be found)

This case is fine -but I would consider the air flow through. I decided to use fully ventilated top and bottom. Amazingly in England we have two weeks of summer at the moment. My desk is at 27deg C (80F) and the top of the fully v case is 40deg C (104F). The amp is working fine although I haven't tried to measure the HS temp under these conditions. (Normally the ambient in our house is nearer 16-20C)

THE KNOB OF BIRGIR will become a legend. ....Strikes a chord, we used to have Nordic sagas when I was at primary school. A very nice bit of skill Dr Gilmore.

And thanks for the post Kerry. That is an inspiration!

Good job all round gentlemen. Will you make the pcb available to us now?

A very interesting design Kerry, I really like the way you've gone about this, thanks for posting it. Look forward to the outcome.

Surely you meant i-spuds ......You're a mad lot, but I like you

Thank you, that information about the extra space around the holes etc, and the bias test point. is very helpful. And you are quite correct to remind me that we have always had the option of the alternative lesser parts on the pcb. That's all I need really. I would like to try that out before too long. Thanks

Yes please, I'd like to have the choice of the bells and whistles job or a simpler alternative. Assuming the low noise/transparency of the amp was not seriously compromised.

I just searched for green nail varnish (!) Repair of photo resist might be possible using it. it dries in a few mins. I found a ref on nerdclub http://nerdclub-uk.blogspot.co.uk/2013/04/nail-varnish-as-solder-resist.html and the green varnish ; http://www.barrym.com/products/nails/paint/all-nail-paints.html Note it must not have metallic flakes in it!! This could take our hobby in a whole new direction.

That's a very good looking build eggil. Well done!

That's great schubert. I'm very pleased that it is up and running so soon. Glad you like it!

Calling you schubert like that. Are you going to have a go at finishing that symphony?

Well done schubert! That didn't take long and it looks very nice. Glad the little problem is sorted.

My first thoughts as well. He's got both the 15v supplies so I suspect overvoltage. I do think that the 25v rating of the 4700uF is cutting it a bit close. I bought mostly what's on the BOM on trust. But I am very tempted to find a similar 35v part. There is no room for mains fluctuations either. If the mains is high we might get over 25v. What value of raw low voltage dc are others getting? schubert will you please measure and let us know the ac voltages going into the PS at the terminals. and the raw low voltage dc. You only need to take a "minute" and then switch it off. you could also check your ac mains voltage coming into the whole thing.

That is very nice. Well done. I have been toying with that sort of layout for a few days and it is great to see you have it going. I would be interested in how warm your room is and how hot your amp gets. Also what resistor /current have you set in the output stage? Very best wishes And I too echo your thanks to Kevin for the circuit and pcb design

Now that's what I'd call a heatsink! I'd be thinking of slicing it into 4 or 5 at around 100mm each. It would go on the sides of a case nicely.

Thanks for that spritzer. As for temp - I have not done accurate heatsink checks yet, other than to note that they are not too hot to touch! The room temp is 20C, the temp in the case next to the heatsinks with the lid on is about 40C. it's running about as warm as I expected, but I will do more checks and report back.

Thank you guys. I expect I'll be asking a number of questions as I get used to this system. Apart from what do those capacitors do? What is good practice with the amps and Stax "earwhatsits". Is it OK to plug in or unplug the phones from a live amp,for example? Any advice on that?

OK if you insist! I basically a retiring guy -this feels like dropping my pants in public. Incidentally, I didn't buy the 3900pF used in the power supply - it wasn't in the circuit diag. I used. Is it for stability or noise control? Cheers