hearingisbelieving

Valve amp help please (blown/dead valve/s???)

39 posts in this topic

It depends on the amp. But with any amp a dummy load it's a good idea if not using speakers

not being funny but you would think they would mention that in the manual.:?

Especially if they already go to the length of listing what the volume control does:doh:

When you say dummy load do you mean using some resistors? if so what value and rating would they have to be?

0

Share this post


Link to post
Share on other sites

As I said, it may not be a problem, depending on the topology. It's more of an issue with pentode our ultra-linear amps as the high impedance of the tube means you can get some very high voltages in the output transformer primary, causing it to be damaged. Triodes have a lower internal impedance, so it's less of an issue.

As a note, such damage is really only likely if you actually try and play music through it.

Ideally use 8 Ohms or so. Up to 20/30 ohms should be fine, it's not critical and 20W should be adequate as a rating.

As I said, it may but be necessary, but the dummy load won't hurt and better safe than sorry.

0

Share this post


Link to post
Share on other sites
As I said, it may not be a problem, depending on the topology. It's more of an issue with pentode our ultra-linear amps as the high impedance of the tube means you can get some very high voltages in the output transformer primary, causing it to be damaged. Triodes have a lower internal impedance, so it's less of an issue.

As a note, such damage is really only likely if you actually try and play music through it.

Ideally use 8 Ohms or so. Up to 20/30 ohms should be fine, it's not critical and 20W should be adequate as a rating.

As I said, it may but be necessary, but the dummy load won't hurt and better safe than sorry.

There's the rub - I was playing music through it when I had my actives connected to the pre-out...

Luckily I have found a competent tech so hopefully he will be able to get to the bottom of this and it wont be too expensive!

0

Share this post


Link to post
Share on other sites

I'm pretty sure it will be fine. If the output transformer was fried, you wouldn't get noises, you'd get silence!

0

Share this post


Link to post
Share on other sites
I'm pretty sure it will be fine. If the output transformer was fried, you wouldn't get noises, you'd get silence!

Wow thats a relief to know as I believe they are the most expensive component in a valve amp - especially AN! Will report back when the tech has inspected the damage...

0

Share this post


Link to post
Share on other sites

Just been informed by email that the Oto is now mended and ready for collection. Picking it up tomorrow night so will report back soon. It took a while for the guy to repair it but for a fixed fee of £90 you cant really complain! As well as the repair he also carried out a couple of small mods i had requested, and a couple he thought might be a good idea for no extra charge:shock:.

Cant wait to hear it sing with the new valves as well!

0

Share this post


Link to post
Share on other sites

For some inexplicable reason I only got 1st page of the thread. I thought that was all of it and offered some sterling advice about 6N14P valves, then when I clicked the reply button the post came up three pages later. I didn't have time to read them all and it seemed best to remove the post, and I was amazingly enough (probably) right. Not v. exciting :roll:

0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.