Also, as I'm no expert on valves, I've ordered a Russian NOS 6SN7 (£12 for two) and Brimar ECC88 (£12 for two).
I notice that some 6SN7's are about £50 each !!!
Yes. I know I only need one of each, but spares are always useful in the valve world.
I notice that some 6SN7's are about £50 each !!!
Yes. I know I only need one of each, but spares are always useful in the valve world.
To quote Tevye, "Tradition!"
I have some exotic 6SN7 (5692, CV1988), but the EH measured just as well.
There's no current running through them and they are low resistance value, so the noise contribution is negligible. Remember, that stage is fed through a potentiometer, which will have an order of magnitude more resistance.
I agree, also their exact value isn't important so the fact that they change value with temperature and time doesn't matter. I don't have any on hand so for me it's extra trouble to seek them out just for grid stoppers. Because of this I don't bother. Easier to just buy metal film like everything else. I always thought another reason to use them for grid stoppers was just to get rid of the stock on hand. 🙂
OUCH - The postage for the Mains Transformer is $249. The transformer was only $29. Still, better to get the right component, the only UK spec component I could find was for a power amp with a King sized price tag.
That's a ridiculous price, it's a cheap transformer. Source something more local or from someone who knows how to get product into Europe at a reasonable cost (Antek, perhaps?).
I'm looking at how to match R11 and R12 to +/- 0.1%.
With a standard DMM the DMMs resolution isn't fine enough.
15K +/- 0.01% gives us 14.985 - 15.015K
On the DMM I could measure 14.98 to 15.01K
With a standard DMM the DMMs resolution isn't fine enough.
15K +/- 0.01% gives us 14.985 - 15.015K
On the DMM I could measure 14.98 to 15.01K
If you are competing against that price, have Sowter make one for you, it's going to be cheaper. SOWTER AUDIO TRANSFORMERS
I'm hoping that I can cancel as I've just found the same transformer at Mouser for £55 incl delivery.
By the way Si. As I'm building the PSU separately, what is the load current that the Impasse presents to the PSU ? It has to be loaded otherwise the 450V caps are right on their limits.
I tried to purchase the transformer from Allied but it has been out of stock for quite some time. I am thinking about using this one:
Antek - AS-1T300
Antek - AS-1T300
It's a little low on voltage, but you should be able to get it to work and get ~390V out of it for the regulator.
How about this one? It has 2 x 320V and even though it is rated at 50VA, it seems to be enough for the ImPasse.
Antek - AS-05T320
Antek - AS-05T320
I was looking for the one SY mentioned in his article, Allied 6K3VG. That one has been out of stock for at least a couple of months. I am planning to use a HIFI 2000 chassis which is only 3 inches tall. Either model of the Hammond will not fit as it comes from the manufacturer. I would have to use different brackets to mount it horizontally.
Have you though about going down the Audio SMPS route. I say Audio with tongue in cheek.
A well filtered SMPS might fit your bill.
A well filtered SMPS might fit your bill.