ShortScale.org

Right I get home waiting to play my new amp that I know is sitting in the hall. Except I've forgotten my keys and my nearest flatmate is the otherside of town.

I busy myself for half an hour in a coffee shop waiting for them to arrive. I get home, I unbox the Laney, let it warm up and slowly turn up the volume. I'm liking what I'm hearing, I switch to the second channel.

Nothing.

I have a look around that back, the cover for the preamp tube for the second channel is missing. The tube looks wonky. I find the cover stuck under the reverb tank.

All tubes are lit but there is still no sound. I let the amp cool down and reseat channel 2s tube, still nothing.

Talk about disappointment. Gotta get on the phone to GAK tomorrow and shout my mouth off. If they didn't test this amp before sending it to me I'm going to be raging.

I'm going to demand a replacement be sent out immediately and they can pick up this one at their leisure.

Ouch.

Sucks, now you're going to be waiting even longer.

Boo urns, sorry to hear that dude.

It's been my understanding that tubes aren't channel-specific, but I may well be wrong. If I'm right, it's a problem with the amp rather than the tubes (since it's working in the other channel fine).

Depends on the design Doog. In the VC30 both channels share the first half of the first 12AX7. The clean channel uses the second half before going on to the third tube doing the phase inverting.

Both sides of the second tube are being used for the higher gain in the second channel.

It's a classic design that a lot of amps use.

Fair enough, I just got schooled. I can live with that.

However, after thinking about it, I just swapped the second and third tubes around. I was thinking if the second tube is duff then putting it in the phase inverter stage will cause both channels to go.

Except both the clean and dirt channels are working. Something is definitely not right. I'll see how it acts over the next few days. Still going to call GAK and give them an ear bashing for sending me it in this condition. Maybe try and get the footswitch out of them

Gotta thank Mike for recommending this book:



I wouldn't have thought about switching the valves had I not read it page to page in the last four days.

That sucks. At least it's working somewhat, would have been worse it it wasn't working at all. Give GAK an earful for sure.

that book is really great! i've read it a B&N twice(well almost)

That sucks dude! Good luck with it all!

I don't know, but is it me or does shipping amps with their tubes removed sound like a good/sensible idea?

euan wrote:I don't know, but is it me or does shipping amps with their tubes removed sound like a good/sensible idea?

yeah that does sound like a good idea too me too.
you should be ok other than the whole waiting thing, i'd be pissed if i were you.try to make them refund your shipping or something.

Yeah I am really pissed about it all. Kinda taken the feeling good factor getting a new amp. I'm really pleased with how it sounds as well, and I'm enjoying the sound of Mustang+cable+amp again.

Cost of shipping back or as I say, they footswitch

shipping with the valves removed would be a horrible idea. some people(alot of people)would most likely complain at having to install the valves themselves. though it does make sense on the not trashing a valve aspect of it.

I don't know. If you were shipping a Triple Rectifier I think you would want to remove the valves. The laws of probability say that one of those valves isn't going to make it through transit.

euan wrote:I don't know. If you were shipping a Triple Rectifier I think you would want to remove the valves. The laws of probability say that one of those valves isn't going to make it through transit.

tr00.

It does look like one of the tubes is a dud and it just works in the phase inverter stage. I don't how easy it's going to be to get another out of GAK. Though technically this amp isn't fit for its intended use.

Hey good jorb on the fix! I would have been all over this but was uot having a few drinks for my friends' birthday.

Basically you did everything absolutely right, swapping the pre's if you're getting any issues with non working channels is absolutely the thing to do, and as you say it sounds like your amp is very similar to my Marshall DSL401 except the Marshall was arranged as V1 (both channels), V2 (both channels again), V3 - overdrive and V4 (Phase Inverter to split the signal to the power amp section.

A 12AX7 is a dual triode and you may have one bad triode, explaining why it works in one position. Get on the phone and kick their ass - the tube should never have been moved in transit, regardless of whether it was shipped in position or not.

Oh and I'm pretty sure I have a few 12AX7s lying around, I can mail you one no problem if you want.

Yeah I was starting to think it was one of the triodes that had gone as well. If you put the tubes back to how they were you can just hear the faintest of signals on max gain and volume.

Gonna call GAK today on my lunch break, I'm sure this is going to be fun. Bus as I say, it's been shipped to me damaged. I doubt it needs to be sent back, it just might be hard getting a replacement tube out of them.

Just phoned GAK, the monkey on the phone couldn't do anything without talking to the returns manager and sound like he had no clue what I was going on about. I've push for three replacement ECC83s for the preamp but he'll have to get back to me about that.