22 April 2014

Amps: Watford Valves, yes Sir.


This is just a short note related to my recent experience with Watford Valves.

I have a drawer full of spare tubes, that correspond to all the tubes I was purchasing trying to bring some life to my amps. Most of my purchases were made to the Tube Amp Doctor (T.A.D.) but, once I've started to be disappointed with their tubes, I went to other European tube dealers, to get even worst results.

I knew about Watford Valves and, I knew they had a strong name but, the expensive exchange rate Euro / Pound, were keeping me out of their online store. This and the fact that the five times I tried to get some guidance from them ended in nothing. Nobody seems to answer you back. This is still my main concern related to Watford Valves. Nobody seems to care about emails.

But, since Watford has some re-tubing kits, specific for some brand and model of amps and, I was in the need to re-tube a couple of amps (Vox Night Train and Fender Hot Rod III Deville) and, my spare stock contained just those tubes I had rejected, I've decided to give a try to one of those kits.

Already mentioned in a previous blog entry, I've successfully re-tubed my Fender Hot Rod III Deville with one of Watford's re-tubing kits and, as soon as those tubes were at home, I did my own tests, with the help of the Orange Divo VT-1000 tester and, I was gratefully surprised with all them being really close to specifications.

Because of that, I wanted to check again  with a couple more amps: the Vox Night Train (complete re-tubing) and the Marshall 1923C 85th Anniversary Combo (just pre-amp tubes, because power tubes are already SED Winged-C EL34s).

Retubing the Vox Night Train

As I did with the tubes for the Deville, I've tested the new tubes as soon as they came from Watford and, before installing them in both amps.

The kit I've used for the Night Train is the kit that's being sold for a Vox AC15, since they have exactly same tube topology and, very similar overall character.

Watford relabels all the tubes that are passing their exhaustive Drive Test with the Harma name.
TAD relabels also the tube that passed their own tests with the TAD name but, I have the impression that TAD tubes have a tolerance range higher than Harma tubes and, therefore, they don't bring the same life to the amp.

The kit for the Vox AC15 comes with a couple of Harma ECC83-RET (retro) pre-amp tubes and a couple of Harma EL84-RET (retro) tubes. Watford doesn't identifies which brand/model is re-labeling but, I had the impression that all them where Mullard reissue (Red Sensor).
Since I had a Mullard 12AX7 in Night Train's preamp and a couple of Mullard EL84 in power amp, comparing my tubes with tubes from Watford, gave me the impression that they were all Mullard reissue.

This is not an issue, because those were exactly the tubes I've chosen time ago for that amp. But, since I remember how they sounded after re-tubing the Night Train, this would be a fire test to see if the relabeled Harma tubes could work the same or better.

I remember that my Night Train was sounding really good (before some tube worn) but, man, now it sounds really stellar.

The Orange Divo doesn't tells me all the history. The readings for the pre-amp tubes where the same I usually get for Mullard reissue 12AX7 tubes: one triode reads 10, the other 11. The readings for both EL84 were 10, while I'm getting readings of 10 (most of times) and 11 for Mullard EL84 reissue tubes.

So, in principle, I was throwing there same tubes, with same readings. So, how that kit from Watford can sound better?.
My suspect is that the difference can be related to other variables and, very specially, to transconductance.

I made a short test, with guitar and some backing tracks and, I was fully satisfied with the sound of the Night Train. Indeed, one more score!.

Retubing the Marshall 1923C 85th Anniversary Combo

I've chosen a Classic / Hi Gain kit for this amp, because I want an early breakup, to be able to cook the tubes at lower volumes.

This time the Harma ECC83-Ret tubes seemed to me JJ ECC83S tubes but, readings where a digit over my usual readings with TAD 12AX7-Cz (JJ ECC83S) tubes. While TAD tubes usually read 8 / 9 (triode A / triode B), Harma tubes read 9 / 10 (V1 and V3), 8 / 10 (V2) and, the balanced one 10 / 11 (PI).

This is the second balance tube from Watford and, both have unbalanced triodes but, both have at least one reading 10 (on specs) and, the unbalanced is just a digit more or less.

Long time ago, I did a lot of swaps to this Marshall, and my conclusion was that there is no other tube that works better in this particular amp than the JJ ECC83S. My suspect is that those ECC83-Ret are effectively JJ ECC83S tubes. If the history repeats, as with the Deville and the Night Train, my favourite amp will come back to life very soon.

I have to re-bias the EL34 to Marshall' specs (45mv). Then, I will be able to evaluate the real impact of those pre-amp tubes, which I hope to test by tomorrow.


It seems that Watford Valves do the best tests on tubes, at least in Europe.
I've wasted a lot of money before, trying to get more affordable tubes, which leaded me to unsatisfactory results and a ton of spare tubes that I will probably have to throw to the trash can.

They won a new customer, indeed. But, I would suggest to Watford to have someone taking care of the email, because not everybody can make an international call that could cost even more than a single tube.

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