Hill Amplification FAQ

If I change my tubes, do I need to re-bias my amplifier?

Most often No, but it is a good idea to check the biasing of new output tubes and knowing how to set the bias should be a important part of owning a tube amp. Our amps are built with easy to access bias test points and adjustment pots. Call Hill Amplification for re-biasing recommendations.

How often should I change my tubes?

Tubes are like lightbulbs - they could go out at any time. Generally, if you're playing hard, tube life can be anywhere from 6 months to a year, although tubes can last much longer than that. Preamp tubes can last indefinitely but do fail also, in my case “ all the time” : )

How do I know if I need to change my tubes?

If your amplifier makes strange noises (hisses or squeals, pops squawks or talks back!), or if it experiences a lack of power or a lack of bottom end.

How do I determine if my preamp tubes or my output tubes need to be changed?

If you're experiencing a lack of bottom end and power, it's probably your output tubes. Sometimes preamp and power tubes will go microphonic or even new tubes can have excessive noise or be microphonic. Tubes are electro mechanical devises and the metal elements inside a tube can become loose or even break causing ringing, howling or produce general feedback problems. It will be more noticeable at louder volumes. Tubes can also be noisy causing popping and crackling noises etc.. You can tap on a tube with the eraser of a pencil to isolate a microphonic tube but not too hard because you can actually damage a tube by banging on it. ( Do not mistake noise from tapping on the first preamp tubes for problems, these tubes are very sensitive and litely taping them makes noise) I feel the best way to is to have a set of known good tubes on hand and just replace the suspected tube. If the problem goes away then you found your tube. If not then the problem may be elsewhere. For Master volume amps- If you're hearing strange sounds coming from your amplifier, turn your gain section up in volume, and slowly turn the master volume down. If the noises persist after the master volume has been turned down, it's an output tube. If the noises go away after turning the master volume down, it's an input tube.

Do you modify amplifiers?

Yes. I will do anything from a simple modification to a one-of-a-kind custom amplifier.

What is the warranty on Hill amplifiers?

Hill Amplifiers have a 10yr warranty from original purchase excluding tubes and speakers and damage caused by neglect. You will need to provide proof of purchase for warranty repairs.

NOTE: If any of our amplifiers have been modified without Hill Amplifications knowledge, permission, or guidance, your warranty is temporarily nullified. Hill Amplification will charge to fix or change any "bad" modifications that have been done to your amplifier, after which your warranty will be reinstated.

I bought a used Hill Amplifier. Can I still get a warranty? Yes!

If you buy a used Hill amplifier and want a new warranty, just send it to us to check out. If it checks out good a new three year warranty will be issued for $42 which covers the checkup and our shop time. If any deficiencies exist we can repair them at a reasonable cost and a new warranty will be issued. You pay shipping both ways.

How do I find out if my amp is under warranty?

Unless it's been modified as such stated in the previous response. On any of our other products, if you are the original owner of the amplifier, and you've had it for ten years or less, it's under warranty. You will need to provide proof of purchase for warranty repairs.

How do I obtain warranty service locally?

You don't. All of our warranty service is done here at our shop.

How do I return my amplifier for servicing?

Call Hill Amplification so you can receive a Return Authorization (RA) number. Speak to our technician and explain what you are returning . When you do return your amplifier, please remember to include your name, address, daytime and evening phone number, and a full description of the problem.

Are your amplifiers all tube?

Yes, our amplifiers are all-tube including the reverb circuits.

Do you build other types of equipment?

Yes we build custom stand alone reverb and vibrato units in custom or vintage style cabs as well as switching boxes and stompboxes of all kinds. Just ask maybe we can help. We’re always interested in doing unique and different things.

Do you do speaker repair?

No not any more, not unless it’s a rare or valuble type. But most of that work I farm out to a friend of mine who is a specialist in that art.

Do you sell tubes?

No I leave that to the big vendors and guys that specialize in that biz. I will say this though, Be careful and only use reputable and well known vendors. If you need a point in the right direction, I’d be glad help.

How long till my amp is done being built or repaired?

That depends? For simple repairs I usually get them done in a few days depending on the parts and my workload. Some parts take a wile to get like a new transformer that’s handmade or a chassis from Bangkok. Cabinets take a few weeks to make also, especially if their exotic designs etc.. A complete custom amp like a big fender or Marshall with custom cabs , usually take 6-8 weeks or even a little longer. Understand that there’s a lot that goes into a custom amplifier and it’s all handmade. If your in a hurry? Buy a mass produced amp. But if you want an exceptional amp tailored to your needs using the finest components available then we’ll be glad to help. But we do try to get things done as fast as possible without compromising quality.