Help - New Tubes for Vox Night Train 50 Head

[wilsa]

Hey all

After some advice. The other guitarist in my band is away in Japan for a couple weeks so am going to use the time to get all my gear sorted, starting with retubing my amp (for the first time).

Is a stock Vox Night Train 50 Watt head. This has 2EL 84s and 4 12ax7s. Have had the amp for about 7-8 months now, getting about 10 - 15 hours use a week. The tubes are the stock vox ones (Chinese made, not sure what brand)

Here are my thoughts/what I am after:

Overdrive Channel: This I have been hardly using for two reasons.
- It is too high gain for my liking, to get the sort of distorion I am after the gain needs to be right down.
- The volume on the channel needs to always be cranked, and this can be an issue with the gain all the way down.

I'm not sure if a changing of the tubes will fix all the problems but after something that would give a lower gain overdrive type sound.

Clean: I have the gain at about 12.00 and it sounds good to me, enjoy the headroom.


So am after some new tubes that when pushed will have a lower level of gain. I don't tend to use power amp distortin so main concern is with the pre-amp tubes. I think with the set up it uses 3 of the 12ax7s on the clean and then the gain channel includes the 4th. The fx loop is bufffered.

Any advice would be great thanks. This is my first Tube amp so am looking forward to seeing the difference a retubing can have.

[Single coil]

A retubing will usually add a bit of brightness back into the amp - Noticed it in my AC30. Stock valves aren't very nice. Also, the NT50 runs EL34's not EL84s... 34s are big buggers, 84s not so much.

Substituting low gain valves where higher gain valves should be can sometimes lead to a ... Pretty bad result. You'll lose volume too.

Best to ask Ryan - I only have little experience and he does this sorta thing for a living.

[AmpShop]

Yep, you could try one or more 5751, 12AY7, 12DW7, 12AT7 (not my favourite for this application), 12AU7 etc.

At least some of the triode stages in the preamp will be shared by the clean channel, so you'd need to review the schematic or go by trial and error to not affect the clean channel too much.

Beyond that though, maybe consider modifying the circuit to reduce gain, or, look at if a different amp if that one isn't right for your needs/tastes

[wilsa]

Cheers. I always get 34s and 84s mixed up. Have thought of a different amp but I really enjoy the clean side. I use pedals for all my gain purposes at the mo, but just feels like a waste not using the second channel. If I replace the tubes, what brand would you recommend?

[AmpShop]

Maybe it's not a waste though, if that's what works for you. I reckon a good chunk of people with multi channel amps only use one channel.

For the output tubes, there's a lot of good EL34 options out there now. My favourites are the JJ E34L and the Tung-Sol EL34B; the new(ish) JJ 6CA7 is nice to for a cross between EL34 and 6L6 flavour.

Preamp tubes:
5751 - JJ 5751
12AU7 - JJ ECC82
12DW7 - JJ ECC832 or ECC823 (the latter may work better depending on circuit)
12AY7 - EHX 12AY7EH
12AT7 - JJ ECC81

The other option is to try 12AX7/ECC83 tubes that test under spec for gain - I have plenty of JJ ECC83S that are like this - while these tubes are generally a 'fail' in terms of meeting spec, they can be just the ticket for dropping gain without changing tone too much (compared to say a 12AT7 which has quite a different tone).