Need new preamp valves

[_tom_]

Well I went with a 3 JJ 12AX7s in the end. Hopefully will arrive in time, not sure how quick Hotrox are as I haven't used em in ages.

[Twinfan]

Hooray!  A decisions!  :lol:

HotRox are usually pretty quick in my experience.

[38thBeatle]

I might be looking to change the pre amp valves in my VC30 so will have a think, do some research and see what happens. I have JJ's in there at the moment and have been very happy with them but there is a bit of hissing action going on. I'll mess with them when I get the chance to see if indeed it is a pre amp valve- having just written all that, I haven't changed the power amp valves since I've had the amp. Decisions decisions.

[Antag]

FWIW, I just got a Harma Cryo high gain preamp kit for my Marshall from Watford Valves.  They arrived two days after I ordered them & first impressions of the sound are very positive.

(38th - they do two kits for the VC30 too - high & low gain :))

[_tom_]

Ordered from Hotrox first thing on Monday and still not arrived. Have a gig tomorrow. Not very impressed! Suppose it's my fault for not paying a bit extra for quicker delivery.

Mr 38th, I've always found my GH to be quite noisy/hissy. So maybe its just the amp, unless the problem has only just started.

[Twinfan]

Sorry to hear that Tom - maybe the Easter hols have screwed things up?

[_tom_]

Yeah, probably. As I said I should have paid extra for quicker service.. It also means I don't have a wah as I ordered a new switch from the same place :(

[hermetico]

I run a swapping dance in my Night Train just yesterday, comparing the stock valves (Sovtek 12AX7-WA) against the following:

- JJ ECC83S
- Electro Harmonix 12AX7
- Tung Sol 12AX7
- TAD 7025-S

JJ ECC83S were an improvement respect of that Sovtek 12AX7-WA. I found the valves cristal clear, well defined and really hard to break up but, unfortunatelly, they sounded too trebly for my amp. I guess those will work in darked voiced amps and when the maximum clean headroom is a must.

EH 12AX7 was the more ballanced valve, slight rolled off low and high ends, warm, silky, clear, defined and with a correct behaviour under high distortion. It broke earlier than the JJ but later than the other two. Same gap I felt from Sovtek to JJ was felt with JJ's and EH. I liked a lot this valve, very natural sounding, no special character just in the center point.

Tung Sol 12AX7, in the same league as EH, slightly darker in low gain, treblier in high gain settings. Powerfull sound, detailed and with balls. The EQ boostes a little bit the bass frequencies and clearly more the high frequencies. Breaks earlier than the EH but later than the TAD. Nice valve also, IMHO.

TAD 7025-S (Mullard-like, as per their description). In the same league as the EH and Tung Sol. Very detailed and well textured in low gain settings. Breaks earlier than all the rest and does it in the most special way. There is some kind of small dust motes in the overdrived sound that remembers me the way as a cranked JCM800 or JTM45 do it.
I think it suits really good Blues and Hard Rock, nice crunch.

So, I will be fine just throwing any of those 3 (TAD, Tung Sol, EH), the quality of sound is quite well the same, only little details are there to choose by taste. The JJ is an improvement respect of the Sovtek WA but, it's in an inferior league of those 3 others.

I have now the TAD in V1 and the EH in V2. I swapped the position of both valves and I didn't hear a noticiable difference.
But, as the test was done with a Fender Strato, maybe I will find that the Tung Sol is a better option with an LP-clon, darker by nature.
I think, a TungSol (brigther and punchier) paired with a TAD (darker and crunchier) can be a winning combo. Will try in one or two weeks.

[martinw]

[Antag]

Thanks for the review hermetico - it's especially interesting to me as I have some TAD 7025s that I haven't yet tried.

ummm martin, was that meant for the post a pic of yourself thread? :)

[38thBeatle]

Cheers Tom. It has been getting a bit noisy for a little while. The amp gets used a lot what with a gig or two each week and a rehearsal or two also each week so I suppose it is to be expected.They have been in about 18 months. 

[hermetico]

Gentleman, what's the meaning of that cr@ppy picture?

[Dmoney]

shes a famous wine taster from british TV

[PhilKing]

I did a different preamp valve shootout with gwEm this week using my JTM45/18.  I had a set of NOS Mazda 12AX7's in it which were sounding good, but I'd picked up some over the last month and thought with 2 sets of ears it woudl be a good time to check them.  I have NOS RFT ECC83, GE 12AX7, Philips 5751's and the Mazda's.  As a control we had new Mullard ECC83's (which had worked well in a prior test we'd done).

New Mullard ECC83 - don't put these in after listening to any NOS valves!  The sound is much flatter and the overdrive is more forced.   They don't have the clarity of any of the NOS

NOS Mazda 12AX7 - Nice top end without being piercing, great low end too.  Mids are a little more recessed than the other NOS tubes, but nothing that the tone control won't take care of

NOS RFT ECC83 - much fatter tube than the Mazda or GE's.  Sound is the sound of rock.  Nice bottom and top, but has more in the mid range and more drive than the Mazda's.

NOS GE 12AX7 - Stellar but they run hot.  The mids are incredible, just the tone that you want for rock and heavy blues.  Still keeps great clarity in the top and has punch in the bottom.  They would be my choice, but the hot running was worrying me a bit and I want to try them in my Ceriatone Overdrive Special.

Philips 5751 - Less drive as you would expect, but brought in some of the Bassman side of the JTM45 design.  Excellent valve for a clear flat tone with no vices. 

So at the end of the day I have a Mazda in V1, and an RFT in V2.  Still listening to see if that's where I'll stay.  I haven't played all the pickup types through it yet, so that might make me rethink things.

If you haven't tried NOS preamp tubes you really should give them a try.  I picked mine up on eBay (the RFT's came from Bulgaria), and didn't pay stupid prices for them.  I know if you're a maker you need a steady supply of matched valves, and also you can tune the amp to suit the valves you recommend, but this really was an eye opener.  The other tubes are a Groove Tubes 12AX7M phase inverter, 2 GT KT66's and a Shuguang 5AR4 rectifier tube.

[Dmoney]

nice.
i have a philips kicking about but i might look out for a mazda.