Preamp Tube Replacement In My Audio System
composer1943
Posts: 4
Is it necessary to disconect all the cables conecting the preamp the amp, CD player, tape recorder, etc. or can I leave the cables connected and just unplug the power cord of the preamp? If I can just unplug the power cord, should I also unplug the amplifier power cord as well?
Best Answer
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Answers
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No need to unplug everything, just make sure the unit is OFF
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Unplugging the AC mains is a best practice, since there would otherwise be AC power line voltage inside the preamp up to the switch (assuming the outlet into which the plug is inserted is live).
Exercise some caution rootin' around inside, but the tube can be (easily) pulled and replaced without any risk of contact with residual charge from a capacitor... which wouldn't be terribly likely in a preamp anyway.
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Thank you both for your advice. If replacing the tubes doesn't get the preamp working again, I guess I'll have to dump it because the manufacturer told me it's too old to repair. (?!?) Then I'll have to figure out if I can use a "non-tube" replacement preamp with the tubed amp that still works fine.
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Eh, any competent repair shop should be able to repair it. If you don't mind me asking, what pre are you referring to here?
BTW, please allow me to offer you a very warm welcome to the Polk Forum.
Tom~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~ -
I would disconnect my tube preamps entirely from the system. Two reasons. One was I had to remove several screws from the case to access the tubes and it was easier to disconnect things and remove the preamp from the rack. Two was so I could avoid the potential for static discharge during the winter months.
Depending on what tube preamp it is and what the problem is it may be more cost effective to buy a new one. But, finding a used one of the same type that still works and cannibalizing it for spare parts could be an option too. Really depends on how much you like the preamp you have and what it's worth. Tubes are also getting expensive.
What tube amp is in the system? There's no reason most solid state preamps wouldn't work with a tube amp. You could even use a cheap used AV receiver to tide you over. -
I replaced the tubes with no luck; the preamp is dead. The experiences I've had with the manufacturer (Van Alstine) make me not want to buy a new preamp from them, although the tubed amp is still a Van Alstine unit. I couldn't take the preamp to a local audio repairman because he told me that Van Alstine wouldn't sell him replacement parts. And Van Alstine didn't even want to try to repair it, no doubt wanting to sell me a new preamp. If anyone feels like recommending a preamp, I'd be very interested in reading those recommendations. A prospective performer wanted to listen to a chamber piece of mine and we had to do that via our TV with lousy sound compared to what the audio system used to produced. I felt like serving the guy popcorn.
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I don't know why you local tech couldn't fix this, I'm pretty sure van alstine uses off the shelf parts. There was one model that had a mute switch with no indicator light, so if it's muted you might not know it.
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Troubleshooting and repair should be pretty straightforward.
As someone asked, where-ish are you located? One of us might be sble to help.
Also, bear in mind that if you have a "source" (CD player, take deck, DAC, phono preamp, tuner) that offers "line level" output and an attenuator (volume control), you don't really need a full-fledged preamp. -
Send me a direct message if you wish, and we can "discuss" more.
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Van Alstine isn't known to be an expensive brand compared to others but they've also been around for decades. What kind of budget are you looking at as a replacement?
At the lower end of domestic brand cost Schiit is worth looking into and they are popular. Freya F: https://www.schiit.com/products/freya-f -
Excellent suggestion from @Emlyn above. Schiit ships quickly, too, if the product is in stock.
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Thank you all for your advice. My wife and I have lived in 5 states and in large cities and small towns in all those states. Now I'm living in a very rural town in Western MA. I think I'm one of the few professional composers left who chose to not be employed by academia. The Hungarian writer Konrád György (George Konrad) once wrote, ”It is not true that a separate peace can be made with the creators. It is not true that they can be herded into the sheepfolds of the universities.” How wrong he was! It's gotten so bad that in spite of my music being praised by some of the best musicians in both the US and Europe, it's very common for performers to tell me in an email or to my face that they "won't even look at a composition written by a composer who doesn't have an .edu email address." This situation seriously affects my income, so I might have to wait until we get our tax refund and spend all of that on a preamp. If I havd to, I'll spend the entire amount on a preamp.
