Valve pre-amp questions

[Knastratt]

I would change the tubes once I noticed degradation of sound. That or like once a year - twice in three years. Nowadays it's not so much about brands but more of age! New old stock tubes are generally much better than new ones. and finding the holy grail of tubes is a nice (though sometimes quite expensive) quest.

And with NOS tubes in a new gadget like the 6176 you can actually make it better. Lots of fitting tubes and a nocturnal shootout is a mere pleasure. Tubes are really different.

Google for +tubes +NOS and you will find a lot. Don't buy used tubes measured "as new". Lots of ripoffs going on.

Look for stocks at local tv shops.

Tubes glow!

[NIGHT'SCHILD]

Hey! If you are looking for some really high-end great sounding tubes there is a place in my hometwon called Antique Electronic Supply they specialize in New Old Stock tubes.

My reccomendation is trying the 12AX7 Telefunken tube ( I believe that is the tube in that pre-amp). The best brands are Telefunken, Amperex "Bugle Boy" (called Bugle Boy because of the logo on the older Amperex tubes), Mullard, and RCA.

I use mostly RCA black-plate tubes made in the 50's and 60's because they give me the bottom end boost I love with tube sounds.

[Broken]

Thanks for the info,

Telefunken have NOS 6072a's advertised on their website but no prices yet.

The pre-amp tube is a 12ax7a, I don't know what the difference is between that and a 12ax7.

What brand is considered the cleanest 12ax7a?

[Ted Nightshade]

FWIW I only change the tubes when something goes microphonic or dies, once I've got some good working tubes in there. Many tubes have been going around here for years and years.

That's once I find some decent sounding tubes to begin with- decent meaning clear, very low noise if it's a mic preamp.

[hollywood_steve]

FWIW I only change the tubes when something goes microphonic or dies, once I've got some good working tubes in there. Many tubes have been going around here for years and years.

That's once I find some decent sounding tubes to begin with- decent meaning clear, very low noise if it's a mic preamp.

I agree. My old Siemens V78 sounds great and I think it has the original (40 years +!) tubes in it. When I purchased it, I sent it to Oliver at Tab-F for a checkup and he replied that it was so clean that it was likely a radio station "spare" that had spent it's life in storage. Other than replacing some dried out caps, he said it was good to go. And I've had the amp now for about 4 or 5 years of limited use. So tubes can last a long time.


I've just bought a used UA 6176. Are there anythings I should do as far a maintenance goes?

Isn't the 6176 a fairly recent product? Like 2 years or so? Unless it was on the road 24/7, I can't see how much could have happened yet. And if it was from a typical project studio, it's probably got less use on it than a lot of "new" gear. I can't imagine that there is much work necessary on something like this.

[max cooper]

Preamp tubes tend to last a really long time. Power output tubes, however, tend to really degrade performance when they're near the end. If an amplifier's power tubes are used to failure point, internal components can get fried. I bought an expensive power supply a few months ago.

[NIGHT'SCHILD]

My answer to that question would have to be Telefunken NOS 12AX7 "Smooth Plate." The store in Tempe, AZ called Antique Electronic Supply carries them for around $80 each. The company has a website called www.tubesandmore.com Check them out.

[faeflora]

Don't **** around. Just buy replacements direct from UA.

[Broken]

I took the 6176 into the studio the other day and it sounds great . I won't bother with new tubes untill I want to change the sound.

Thanks