[Ant1Xr1st]

runeight, The 'speed' of e12 low because of a relay. it can disconnect the load only for 20ms. I have 2 ideas - try to use a reed switch (its 10 times faster then the relay), or try the mosfet switch...

 

[balderon]

Quote:

Originally Posted by fishski13 /img/forum/go_quote.gif i need to try these. sorry, i'm too lazy to search, where's best place to buy?

I picked up a strong pair of BB's on E-Bay and have been very pleased with the sound! Apparently there are many fakes out there and I would suggest reading Joe's Tube Lore - 6DJ8 specifically the section labeled "Danger Will Robinson!".

Has anyone compared the US Amperex 6922, PQ, white label and the BB's?

 

[balderon]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). anyone notice a significant improvement?

I replaced C3/C4 with Auricaps but I don't know if anyone would classify these as boutiques. Although my ears did not hear a huge difference in the sound. IMO I would say more warm, rich sounding, mid range.

 

[runeight]

Quote:

Originally Posted by Ant1Xr1st /img/forum/go_quote.gif runeight, The 'speed' of e12 low because of a relay. it can disconnect the load only for 20ms. I have 2 ideas - try to use a reed switch (its 10 times faster then the relay), or try the mosfet switch...

ant1xr1st, the e12 is slow (for what we're talking about) for two reasons. One reason is the relay the other is its built-in time constant. This time-constant is set so that the e12 does not respond quickly to short duration DC excursions. I know that you already know this.

So, a faster relay definitely helps but the e12 will always take 20ms or more to engage because of its integration time.

It is true, also, that we are discussing potential problems that would be very, very rare, such as a plate to cathode arc or something similar that would bring either of the rails to the output very fast. If this kind of thing never happens then the e12 will be sufficient for anything else that I can think of. But anything that shorts the output to either rail will blow the headphones before the e12 will engage.

Which doesn't mean you shouldn't try the idea. It just means that you may run this amp for 100 years and never have a problem. Or you may run it for two days and blow your headphones. But, it's still a good idea.

 

[Ant1Xr1st]

runeight, you are right) But now i have much simple idea - just add two tvr-diode (inline, opposite to each other) to the output

 

[runeight]

Yes, that should work.

 

[dean0]

Iam populating the boards, but I have a simple question for you guys.
What is the orientation of the LED's on the Amp boards?
There seems to be no indication on the silkscreen.
Regards
Dean

 

[milosz]

I built a Bijou, and love it. I know very little about the Little Dot MK III (or it's tube-rolled, better-parts version the MK IV) - how does the Little Dot Mk III compare to the Bijou?

 

[cfcubed]

Quote:

Originally Posted by balderon /img/forum/go_quote.gif Has anyone compared the US Amperex 6922, PQ, white label and the BB's?

I did but not in this amp, in the CTH. Played quite a bit w/cans in my sig & prefer my 6922 PQ over my 6dj8 BB. Perhaps because PQ was NOS & BB used (but tested very good). BTW as has been said here - BBs on the bay could be long in the tooth.

 

[regal]

IMO a good pair of BB's beats the 6922 PQ's in this amp. The 6922 aren't as smooth probably because they like more current than 6DJ8's.

 

[dean0]

Need some confirmation before I wire up the trafo. Im using the Hammond 370FX.
For UK voltage, what should I use on primary 220vac or 240vac, does it matter?

For 240vac;

-Connect Brown to Black
-Blue (Active)
-White (Neutral)

Look okay?
Info from here;
Hammond Mfg. - Universal Primary - "Classic" Power Transformers

ps Can the Chassis Earth from the IEC connector be connected to the star Ground?

Thanks

 

[dean0]

anyone?

 

[runeight]

Do you know what your mains voltage is? If you do I would try setting the primary for that first to see what you get.

 

[dean0]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif Do you know what your mains voltage is? If you do I would try setting the primary for that first to see what you get.

yes, uk voltage varies from 220v-240v, so what would be best?

 

[runeight]

Try the 240V wiring first. See if you can dial up the B+ to 250V when powering the amps. If you can't then wire for 220V. Let us know how you do.