Mog Posted November 21, 2012 Share Posted November 21, 2012 Story kids? I've decided to stick a new pre-amp tube into the Hartke. I know a few members have switched the 12ax7 in theirs and I'm looking for opinions based on a few months gigging experience. So far I'm leaning towards an ECC803S but any other options/opinions would be welcome. Quote Link to comment Share on other sites More sharing options...
paul_5 Posted November 21, 2012 Share Posted November 21, 2012 I've had a couple of different tubes in these heads. The first was a Tungsol 12AX7 that took away some of the 'twangy' sharp top and mellowed it out a bit, currently I've got a JJ 12AU7 in there just because. Obviously to get the full 500W output you need a 12AX7, not an AU7, but there we are. Quote Link to comment Share on other sites More sharing options...
Dood Posted November 23, 2012 Share Posted November 23, 2012 [quote name='paul_5' timestamp='1353538441' post='1875946'] Obviously to get the full 500W output you need a 12AX7, not an AU7, but there we are. [/quote] I'd say that although the gain was lower in the AU7, as long as your bass output was high enough, then using the gain control on the front of the amp, you'd easily be able to get your level up accordingly. That said, I'd ask why anyone would want to put an AU7 in to the pre of an LH head, unless it was purely for the sound of the valve. Backing off the gain on an LH head is actually a bit pointless, as it's not designed to distort or overdrive in the first place. Even with my basses with a very high output, plugging in to the non-padded input still kept things clean. My fave AX7 / ECC83 in the LH head was a premium JJ. I *think* it was an ECC83S, cheap and pretty silent with a nice presence that sounded a lot clearer and articulate than standard Sovtek 12ax7wa's which in comparison always sound a bit stodgy. Quote Link to comment Share on other sites More sharing options...
Mog Posted November 23, 2012 Author Share Posted November 23, 2012 Cheers guys. Would the pre-amp tube have that much of an impact on the output wattage? I was assuming that it was a tube pre and transistor power section. Quote Link to comment Share on other sites More sharing options...
paul_5 Posted November 23, 2012 Share Posted November 23, 2012 Dood's right, I put the AU7 in my pre stage just because it was a warmer sound. As far as output wattage goes if you put an AU7 instead of an AX7 with a passive bass then the output would be reduces. If you put an AU7 in and used a hight output bass then you'd probably not notice much difference. Basically a 12AX7 (ECC83 in English) has 100µ of gain, the AU7 has about 60 (depending on the type of valve). If you fancy having a play around with different valves then I'd recommend a call to Martin at Watford Valves - seriously knowledgeable fella on all things valve. It's not a short phone call though... Quote Link to comment Share on other sites More sharing options...
Mog Posted November 23, 2012 Author Share Posted November 23, 2012 Cheers Paul. Quote Link to comment Share on other sites More sharing options...
barkin Posted November 23, 2012 Share Posted November 23, 2012 I've just received a JJ ECC833 to try in my LH500 - no real need, but I'm curious and saw it recommended somewhere. Hope to get chance to slot in in over the weekend - I'll report my findings back here. Quote Link to comment Share on other sites More sharing options...
Valhalalf Posted November 26, 2012 Share Posted November 26, 2012 I swapped out the Groove Tubes 12AX7 that was in my LH500 head when I bought it for a JJ ECC803s which loads of forums suggested. I was surprissed at how much I noticed the difference. The head lost all the brittle top end and rounded out and balanced the low end, great purchase for only a tenner. Quote Link to comment Share on other sites More sharing options...
barkin Posted November 28, 2012 Share Posted November 28, 2012 [quote name='barkin' timestamp='1353693910' post='1877613'] I've just received a JJ ECC833 to try in my LH500 - no real need, but I'm curious and saw it recommended somewhere. Hope to get chance to slot in in over the weekend - I'll report my findings back here. [/quote] Whoops - typo...that should have read ECC83s Popped it in at the weekend - at noodling around at home volume it sounds a bit different, but not massively so. Perhaps a bit warmer and more rounded in the lows, and the highs don't sound quite as shrill as the Sovtek 12AX7 that was in there. Definitely quieter though Quote Link to comment Share on other sites More sharing options...
Mog Posted November 29, 2012 Author Share Posted November 29, 2012 Sorry lads, I didnt log in since last week. Cheers for the input. Quote Link to comment Share on other sites More sharing options...
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