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In Reply to: Re: Check the archives,Welborne's the winner. posted by Paul Folbrecht on October 15, 2006 at 13:09:30:
I built the Welborne DRD 45 and a good friend has the 300B. Mine was tube rectified, his is solid state.The 45 had little of the bass punch I heard with the Yamamoto and even less headroom for dynamics. That, with OS RCA and NU tubes. Yes, I know, 2 watts but everything in proportion.
The 300B with EH power tubes is better in every way: more dynamic, nice mids and a clear top end. More musical. Still, not a favorite. I have disliked the Sovtek 6N1p in other amps and maybe that's what holds these back. Too detailed and dry for my taste, but perhaps not for others.
'The beatings will continue until morale improves'
Follow Ups:
I have both the Welborne 45 tube rectifed DRD and the 300b DRD SS rectified amps. On my 6 foot tall horn speakers twin JBL 15" woofer bass bins I had no lack of bass using a single pair of 45 mono blocks driving my 2-way horn set up with a passive crossover. Of course my bass bins are 100dB efficient at 1 Watt and my horns are around 112dB efficient @ 1W. Still no lack of bass using just the single pair of 45 DRD amps. I prefer the 45 tube sound for the horns because to my ears the 45 makes the voices much more natural and more realistic sounding to my ears. The 300b DRD are also very musical and very good sounding. I would not describe their sound as sterile to my ears. Again the bass was tight and not lacking on either pair of amplifiers with my speakers. I used both individually for many months as single system amplifirs. I used the 45 and 300b with passive crossovers before going to a active speaker crossover to biamplify my system. The one thing I will mention is it took a LONG time for my new 45 DRD amps to fully open up. They sounded good to begin with and got better over the first 50 hours. But after some months they just opened up and bloomed. I had to get up from the next room to see if something was wrong with my stereo.. Give them time to settle in before you start serious tweaking like capacitor changes or real critical listening. Have fun with your Welborne DRD amps. You will find the quality of the parts used, and the fit and finish was very good on the Welborn amplifiers. They Welborne amplifiers look much nicer when viewed in person than the images on his web site. I have used a 100 wpc CJ tube amplifier and my pair of Klimo push pull EL34 amps. The Klimo were the first pair of ss rectified amps I owned. The CJ is gone now but the Klimo mono block amplifiers are still are used on occasion in my systems. I still use both the Welborne 45 and 300b mono block amps the most together with my vacuum tube active speaker crossover to drive my stereo. Enjoy your new Welborne amps! John
When I asked Ron W about the sovtek 6N1P, he answered that he thought the 6N1P was the best tube in his design.
He did not mention "sovtek", just 6N1P. There are not many factories doing 6N1P, so sovtek may be almost the only (or the easiest) choice.That said, I don´t have any other 6N1P, have tried just Siemens E288CC, more meat on the bones than the sovteks, though this tube´s midrange is not the most liquid (my 300Bs are TJ mesh plate ceramic base).
Maybe a pair of good 7308-6DJ8-6922-E88CC-E(1or2)88CC, Amperex or even Mullard, will do the trick with that said DRD300Bs thinness.
Ron W says that you can install any 7308-6922 tube, but I don´t know how it would affect the whole sonics, those have not exactly the same specs than 6N1P.
_____________________________________I am from Galicia, so if you find me in a staircase, you won´t know whether I go up or down ...
Maybe a pair of good 7308-6DJ8-6922-E88CC-E(1or2)88CC, Amperex or even Mullard, will do the trick with that said DRD300Bs thinness.> >The best valve to use is the ECC40. You need to replace the 9 pin base with a rimlock one. Both available on ebay in europe. Much better than any 6922 or 6N1P. This valve is a real sleeper these days, but was the valve of choice in a lot of German gear and studio equipment of the time.
Just did a quick web search and came across a couple of raving reviews for this tube.On Bjørn Kolbrek's Tube Distortion page , he states:
This is a collection of measurements made on most of the tube types I have. I wanted to find the most linear tubes to use in the ampifiers I make. This is THD measurements, but I have viewed the output from the distortion analyzer on a scope, and usually the second harmonic dominate. Measurements are made over a wide range of levels, from 1Vrms (or 0,5Vrms) to 100Vrms across the anode resistor. At the lowest levels, measurements are strongly influenced by noise, so don't take those figures to serious. Everything above 5V should be reliable...The best tubes seems to be E80CC, E88CC and ECC40. They all have mu in order of 20-40, so it seems that low mu triodes are more linear than high mu ones. But there are exeptions, like ECC82.
And from The Rimlock Project
ECC40 magnificent doubletriodeThe idea of using rimlock tubes was born quite a while ago .
I modified several old Philips EL34 push pull amplifiers in the past and most of these amps used the ECC40 doubletriode serving as inputstage / phase inverter . The most famous application is the one that use a 150K anoderesistor and a 1K7 kathoderesistor at the first triodesection.
The second ECC40 section serves as phase invertor using two identical ( 150K )resistors at both the anode and kathode. Input stage and phase invertor are DC-coupled and can work both on a 250 or 350 volt power supply. With 350 volt supply the application can deliver a proper 30 Volt effective output signal at 1% THD. More than enough in most cases!
Please take a look at the ECC40 PDF file ( figure B ). I can asure you this application is sounding fantastic too, I can highly recommend it to all "expiriment freaky" guys over there, you won't be disappointed ! Wanna bet? Try and taste it!!
Of course I can only speak for myself here , but one thing became very clear to me:
The ECC40 is surely a "damn good" tube to use as a signal amplifier at the input of any serious audio amplifier. Lot's of spacious sound, smooth but detailed from the bottom to the top!I decided to go on with this tube at the Rimlock Project, to increase the tubes performance ( voltage swing capability and lower the Rout ) I paralleled both triode sections.
Kind of gives me goosebumps to think the DRD's could be taken to another level of performance with just a simple socket change.
Kind of gives me goosebumps to think the DRD's could be taken to another level of performance with just a simple socket change. > >I've seen two rimlock sockets - I have loads of the ordinary ones which are slightly bigger than a 9 pin socket. I have just a single pair of ones with ceramic base which are a straight drop in to a 9 pin hole. No doubt these can be found in Europe somewhere but they are certainly rarer. They would make the conversion less problematic - it would be a drag to file out the chassis holes.
When I originally did a load of listening tests on 9 pin valves, I used the ECC40 in an adapter I made so it plugged into a 6922 base. I have a few ECC40s if anybody's interested. I'm in London UK. Andy
I'll need to double-check with Ron Welborne about substituting the ECC40 without other mods. Also, I need to be able to track down some rimlock sockets.
nt
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