[Dominat0r]

i thought ground loops only happen if the device is turned on or power running through it.

My hum only happens when my amp is OFF. If i turn it on, the hum goes away.

So no danger in running a different bias for my tubes?

Also, i guess my CBS Fk6s are worn out...cause the new ones you sent me nate dont suffer from the same distortion as mine.

Sounds much much much cleaner...even though both sets have exactly the same markings, printed the same and in the same spot. Just the ones i have have a smaller flash getting then the ones you sent me.

 

[n_maher]

Don't really know what to say about the hum situation Dom. But As far as I know you can't do any harm to the amp by trying the different bias positions regardless of whatever tube is in there. If you run the bias too high you could potentially shorten the life of the tube and if the bias isn't playing nice with the tube you'll get more distortion, as you found with the original set of FK6s that you had. That's not to say that the tubes are bad really, only that the normal biasing position is no longer providing good results. That brings us to one of the other joys of the amp, cheap tubes. I think you can still get the different varieties for less than $4 a tube at most places. At least you could the last time that I bought some, which was probably a year or so ago.

 

[pirate6955]

anytime there is a physical connection there can be a ground loop.
the state of your ground is changing with your power switch. exactly
how or why i can not answer as i haven't seen the schematic or even
the power cord, i.e. 2 or three prong. i dunno if its a two pole switch
opening the hot and neut together. etc. blah blah....

if you get a set of tubes you like and want to run a good while then
properly biasing them would be the way to go.

my two cents....

 

[Tyll Hertsens]

Hi Dom! Sorry I don't have any suggestions on the hum issue, but I can tell you that those tubes are remarkable insensitive to bias changes. That's why we could use a simple switch on the front---just gets the bias close enough for each tube type. Pete told me those tubes were for car radios and as such had to be able to operate with batteries of varying charge state. So I don;t think you have to worry about the bias switch position too much.

 

[Dominat0r]

awesome, thanks....honestly i tried it for like 10mins...used the 12AE6A setting with the FK6 tube and it sounds kinda nice, cept for a tad bit of a stale sounding bass...like instance bass decay.

is there any voltage difference between the bias switch or just a simple buffer change?

 

[Dominat0r]

just a few quick questions as using the HR millet as a preamp.

1- just need confirmation, the sound is actually coming from the tubes or does this bypass the tube? Im thinking it does cause the volume control works on the HR. Which leads me to question....

3- What is the recommended volume setting for using it as a preamp? Im thinking 50% at low gain?

2- is it ok to have headphones connected to the amp and have the rear output on at the same time?

 

[n_maher]

Quote:

Originally Posted by HighLife /img/forum/go_quote.gif 1- just need confirmation, the sound is actually coming from the tubes or does this bypass the tube? Im thinking it does cause the volume control works on the HR. Which leads me to question....

My understanding is that all the preamp switch does is disable the front panel headphone jack. The circuitry involved remains the same.

Quote:

3- What is the recommended volume setting for using it as a preamp? Im thinking 50% at low gain?

I don't think it'll matter much, so I wouldn't worry about it at all.

Quote:

2- is it ok to have headphones connected to the amp and have the rear output on at the same time?

If you're not getting sound out of the headphones while using the preamp I don't see the harm. If the headphones are still working (highly unlikely) then I would recommend unplugging them.

 

[Dominat0r]

awesome thanks nate...again you are my personal savior. Really enjoying the FK6s you sent me.

 

[Dominat0r]

Just a heads up....im really starting to enjoy this amp. At first i didnt just how great this amp is.

Using for my headphones, as a preamp and being able to swap between sources is just fantastic.

This amp has really brought a whole new level to my music experience. God bless Tyll and the whole Headroom crew for coming up with something like this. Very versatile, very rich, detailed sounding.

 

[MoNelly]

I recently upgraded to the amp myself, and I'm beyond pleased.

In addition to feeding my growing collection of headphones (it seems to have a particular synergy with my Senn 600s), I'm also using it as a preamp to my Audioengine A2s on the desktop.

Love it, love it, love it. And I haven't even really begun experimenting with the different included tubes yet!

 

[Dominat0r]

at first i liked the 12AE6A more then any other, however now i can say i like the set of 12FK6s that Nate sent me the best.

Im blown away at my Sleeks right now, im using them with my millet, using the low gain. Its awesome how much sound these have together...very nice pairing imo.

 

[Dominat0r]

woot my millett will go done in history since they are not for sale anymore...

Tyll want to trade me a balanced desktop? =) /snicker