A friend of mine who made a load of ODS amps said he could hear absolutely no difference when swapping 6L6's for EL34's in the same amp at normal gig volumes.
I kind of agree with this statement But I wouldn't say "no difference" It also depends on which PI your using either the Bluesmaster or the 183/124/102 (fender type). The ladder being a bit hotter driving the grids harder. Still by the time you get the thing to the point where the output section starts to go things in the room start rattling
For me, there are a few things I notice about the Pentodes that are pretty cool. 1st would be the touch sensitivity is elevated I generally find myself backing off a bit with the 34's and not needing to play as hard to get the thing to really respond. The 2nd would be something about how the mids are a bit more forward sounding. Almost like you can climb in the note (if that makes some sense) they also compress faster than the 6L's and will break-up quicker if you can get em there. when they go they are smoooth.
The negatives:
They dont seem to have that big full low-end bloom like the 6L's but still with a quad of 34's is not that big of a deal!. The 34's have a wimpy screen supply and are a real finicky tube, and have a tendency to drift around and don't like the back of a truck. (especially the new ones). Wing C's /Siemens/RFT/Amperex 6C7 soft vacuum (killer) and Mullards are all good sounding tubes!.
I've got a set of Mullards but they're old ones pulled from an old amp. They work fine, do output valves wear out sonically or if they're working do they just keep their sound until they die?
Depends on how many hours they have on them. Generally what happens is they start to drift further apart becoming mismatched. Remember they all have to be fairly closely matched if you want the output section to be balanced.You may also want to go with a 10k PI balance trimmer and do some swapping around if you find a quad that are not closely matched!.If you get them in and they sound good use em till they don't or die!
Tony
Thanks Tony,
from what you 've said it still seems like it's going to be worthwhile building this thing from the point of view of it sound 'different enough' from my #102. from what you describe it will be a great amp. It does make the issue of too much choice even more of a problem but hey, it's not a bad thing when you've have too much choice of amps like these.
And....who know's they may end up being an asset I can seel down the line if things get tough. I never take things for granted in this business
Everyone that has Played 183 all have good things to say about it!. Remember 183 is an aggressive sounding amp with plenty of low-end on the overdrive side which is perfect for 34's! it's a ROCKER!
Tony
" The psychics on my bench is the same as Dumble'"
You will love the overdrive tones that the el34 tubes put out with that amp, nice and tight and the mids will drive nicely!
It will definitely be different than the 102 !
I like the blue work mat you have, looks like it makes cleaning up easier.
an old school, 'modern' precision power supply, with some creative underboard wiring
Interesting that the only 330uf/400v caps available now are these type which are quite small actually. Makes for a nice looking power board though I think.
norburybrook wrote: ↑Wed Jan 09, 2019 11:06 pm
an old school, 'modern' precision power supply, with some creative underboard wiring
Interesting that the only 330uf/400v caps available now are these type which are quite small actually. Makes for a nice looking power board though I think.
M
I ended up using tall radial caps but I had to lay them down on their sides. I used RTV on the bottom and between them. It seems stable but I like your solution with shorter axial caps standing upright a little better. Where did you source your 330uF caps from?
Last edited by donvan on Mon Jan 14, 2019 3:25 pm, edited 1 time in total.
But I wouldn't say "no difference" It also depends on which PI your using either the Bluesmaster or the 183/124/102 (fender type). The ladder being a bit hotter driving the grids harder. Still by the time you get the thing to the point where the output section starts to go things in the room start rattling
