Preamp Deal of the Century

Slowhand - the 5y3 is a directly-heated full-wave rectifier. like all directly-heated recitifier it doesn't have a slow startup. this means that every time you power on the preamp you are stripping the cathodes. it damages your tubes and i believe the preamp's capacitors also. the sound you describe is typical of directly-heated recitifiers. most people prefer the sound of directly-heated recitifiers. if you choose to continue using it i wouldn't power the preamp down.

Slowhand... Pay attention to Jazzdude's post here! Good catch Jazzdude. I wouldn't worry about damaging the capacitors, however as Jazzdude correctly pointed out....you must leave your preamp powered up or you will certainly experience a premature tube life of both the regulators and the 6sn7's. I do concurr with your observations of it's sound though, exactly the reason why I use the Bendex 6106 as my rectifier of choice in both the syrah and the cortese. The bendex 6106 specs out closer to the 5y3 electrically than any of the recommended "indirectly" heated rectifiers, It was developed exclusively for the US military to be used as a direct sub for the 5y3.Interesting though: Before I discovered the 6106, I was so very impressed with the sound of the 5y3, I would power up the syrah for about 1/2 an hour with the mullard gz34 in place and then "quicky" sub in the 5y3 to prevent the cathode stripping Jazzdude is alluding to.

That's a "bummer" guys. I really love the sound of this combo of tubes. David, when you talk about "quickly" subbing in the 5y3, do you leave the preamp on and pull out the GZ34 and put in the 5y3? Can you clarify that for me, and does it harm the preamp or tubes? I thought I heard somewhere that the Supratek can be ran without a tube in the rectifier position, although it is not recommended. Thanks for bringing this to my attention Jazzdude.

Just received my tricked up Grange last week. Order was placed in late November. Be patient; it is well worth the wait.

Hi Slowhand. No.......without a rectifier, the preamp would not power up. No rectifier = no power. The rectifiers's duty is to convert the AC voltage[ 115-120 volts alternating current] from the wall plug to 6 volts DC [direct current] for operating the other tubes in the preamp. The regulator tubes[6L6,6f6 etc] are used to smooth the residual ripple in the dc voltage "after" the rectifier has converted the ac to dc. If you want to use the preamp with the 5y3 for rectification duty, there is a proceedure you can use to prevent or minimilize any cathode stripping of the other tubes. It's a bit of an inconvenience but it can be done. Power up the preamp for at least 5 minutes with the stock rectifier,this allows the other tubes to slowly turn on and stabalize in the circuit.Then turn off the preamp and quickly insert the 5y3 in place of the gz34 and turn it back on "immediately". "NOTE" Please understand that I am "not" recommending substitution of the stock rectifier with the 5y3 or any other directly heated rectifier for that matter! Warming the cathodes or heaters of the 6sn7's and the regulation tubes with the recommended rectifiers will minimilize the cathode stripping of those tubes. Cathode stripping is caused by the tubes being subjected to a blast of full voltage before they have had a chance to warm up and stabilize themselves in the circuit. Man...O... man.... Mick would surely be rolling his eyes if he reads this post!