dave

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About dave

  • Rank
    incurable tinkerer
  • Birthday 23/11/1969

Personal Info

  • Location
    cambs
  • Real Name
    dave

Wigwam Info

  • Turn Table
    Pioneer PL L1000
  • Tone Arm & Cartridge
    Shure M97xe
  • SUT / Phono Stage
    834p tweeked
  • Digital Source 1
    eternal cd player
  • Digital Source 2
    Teknica tv tuner
  • Pre-Amp
    tubed dynaco PAT4
  • Power Amp/s
    diy Fast Class A
  • My Speakers
    Wharfedale Teasdale
  • Trade Status
    I am not in the Hi-Fi trade

Recent Profile Visitors

1,989 profile views
  1. Does look remarkably similar to Citronic CX34, which I have and don't really care for. That is just my opinion, for what its worth, perfectly functional unit, just did not really do what I wanted. I wonder if the DBX uses better parts.... Similar to the Beringer too, probably all made in the same place.
  2. Problem is for ordinary mortals like myself(?), I have a carefully designed NOS valve dac in my CD player, and likewise nice valve preamp, then running it into mass market cheap as chips ADC in my Behringer, and then back out of another similar DAC and accompanying mid-fi analog electronics feels wrong and is can be audible, but are the benefits greater than the cost? Today's opinion, surprised how transparent/ clean the DEQ2496 is, a little less so the DCX2696.
  3. Asleep at the wheel... This is going back a bit (to the last millennium) but I used to work for BSS, before they got swallowed up into the Harman group. They were perhaps one of the pioneers of active crossovers, and their kit were used extensively by the likes of Pink Floyd in the 90's for there huge rigs. I had particular experience of the FDS360 which was a stereo 3 way crossover (well not actually... more of a mono, max 4 way) with cards for setting up crossover frequencies, slopes and even a limited amount of EQ, also the FDS310 which had front panel knob adjustable crossover frequencies. I also have a more recent far eastern cheap and cheerful 2x3 way active crossover. Some of these BSS units found there was back into engineers home for "evaluation". The 310 was an unpleasant sounding unit. The 360 a bit better but had a significant fingerprint. A few years ago Serge and another had a 360 based active system at Kegworth. I recognised the fingerprint. I am sure the 360 could be tweaked a bit with some better opamps, bypassing parts of the circuit, like the balanced inputs and outputs and limiter for example, but a lot of work. I have a Behringer DCX2496, and currently plumbed into my all valve system is a DEQ2496 (equaliser not a crossover). These are significantly better IMO, and wouldn't hesitate to recommend one over a 360, 310 or the cheap and cheerful. I also had some experience of the 926, a computer controlled analog 2 channel parametric equaliser with 6 eqs per side. that was a thing of wonder and didn't sound that bad. Its pink noise auto speaker calibration always seemed to work wonders. I can't say the same of the DEQ unfortunately, but that may be because I am not really familiar with it. I have no experience of Dirac or mini DSPs. In my list of back burner, may get round to it one day, is a valve active crossover, most likely first order 2 way, with some limited EQ. One day................
  4. dave

    Building a 300b SE amp.

    Oh the junkie can't help himself, for another fix.... Arrrr. Got some of those EL12n s on order and some sockets, I think I should be ok with the filament bias for the 4P1L thanks, but will wait for the outline circuit, with approx. values / voltages. Seems cathode bias is recommended for the EL12 due to the high transconductance?
  5. Definitely in best sound quality ever place now with the seamless integration of the drivers, little events in clinical analytical detail, whilst still maintaining a big rich warm textured and layered sound. And the imaging much improved, although still a little odd. Enjoying the extra oomph of the Quad iis for a bit more level, enjoyed a performance of Mussorgsky's pictures at an exhibition from living stereo CD for the first time at approaching back row realistic levels, well it felt like it anyway. The first time I have "connected" with the CD, loved an original vinyl copy I had, and then got rid off, duh. Never got on with the CD, found it kind of lacking, but now, yes better than the record (probably). Yes, the bass could have more resolving power, but satisfying depth and "presence", and the ii's are so "slow", but whatever, only really a problem on some material, and sometimes it is nicer to sit back and wallow, than be hanging on for dear life to the edge of the seat, trying to keep up... Quite mystified how changing one value - 6u8 to 1u6 of the tweeter crossover, well quite a change actually, but seems to have swept away the galactic scale small, but still troubling problems, that were marring the overall performance..
  6. dave

    Building a 300b SE amp.

    Ok, I have a couple 4k transformers, and some 4P1L s somewhere. Sounds like a fun project.
  7. dave

    Building a 300b SE amp.

    All interesting stuff. I was reading about the GU50 on the jacmusic site: https://jacmusic.com/techcorner/ARTICLES/English/Portraits/GM50/index-GM50-Portraits.html He says it is very like a 300b... I have some already as I like the idea of military spec hardware.... I have decided I need a "triode" amp, so this makes your adventure all the more interesting. Mr jacmusic also has the GU50 as EL152 on his price list, which in retrospect to my dislexic brain looks like EL12n... I haven't chosen a driver stage yet, just assembling some feasibility iron from my pile/ stash. 2k6 transformer and about 340v HT ought to be ok enough? GU50 quite chunky.
  8. dave

    Building a 300b SE amp.

    Hi, is the el12 triode connected? Contemplating a Gu50 triode connected amp....
  9. Confused of cambridge back again..... Decided to do a bit more probing today, some near field sanity checks, was horrified to see the lumpy response of the Accuton. Eventually realised I still had the Beringers "correction" turned on. Turning this off restored a degree of normality, a gently sloping baffle step, culminating in a little peak at 2 k, and then a smooth roll off. The tweeters also looked remarcably well behaved. But they were going down to 1k. The cross over is supposed to be 2k, and I was still using the similar cap to the LX5. This overlap in the crossover seemed to be doing all sorts of peculiar things. So I added a 2.2uF in series with the tweeter, and a miraculous transformation has occurred. I really can explain why it made so much difference, but the paint rollers are gone the tweets are angled in slightly more, and I have a pretty good response up to 20k. Oh and it sounds lovely, smooth, crisp, well integrated and clear. Didn't know the Quad iis had it in them. A little slow and boring, (ii, I am looking at you) but otherwise very nice. It could be that we have the log burner running in the other room, there is circumstantial positive sound quality correlation there, but anyway, another small step forwards.
  10. Stopped being friends with 2496, decided it's narrowband corrections in the upper ranges too audible. Gr. Also whilst pondering the stacked tweeter array, it has a peculiar radiation pattern. I guess if I did some maths / thinking it would make some more sense, but on axis it has quite strong forward output between 5-10k, which is why I rotated 45 degrees. Paint rollers came to mind, and chopped by 1cm, they fit quite well. With some experimentation placing them up close and on axis tames the 5-10k output quite nicely, will have to get some smaller ones to try because losing some >10k output, (could be HMV amp). This has resulted in a more civilized less lumpy top end response. I have to turn the tweeter up a bit to compensate, but seems fine for a quick test. I will have to address the un-attenuated rear radiation. In this mood of general DSP disgruntlement I had a go at re-tuning the whole setup, I have 4 levels to adjust per speaker, mainly by ear using pink noise, trying to get the smoothest integration between drivers. This was moderately successful and ended up with a gently dropping frequency response. I then tried another auto EQ and this time the the result was a bit more palatable, so begrudgingly on speaking terms with the 2496 at the moment. The overall sound still has quite a cool quality. I like warm. At all times the speaker sounds wonderful on you tube videos. I am beginning to feel this is not the best indicator of overall goodness. With the HMV amp, it sounds super clean, but ironically I suspect it is not the lowest distortion amp, and i think this is contributing some lack of clarity in complex tracks. Not sure. Not very familiar with the HMV amp, but want warmth, Quad ii is the answer to that. So swapped them in and now more warm sounding. For this to be a successful speaker for me, I have to be able to play anything for extended periods, I can't honestly say I am there yet, but with these latest adjustments feel like I have taken another small step closer. Will have another iteration of the manual tune - auto tune cycle soon. Will live with it for a bit, see how I get on.
  11. From my mid teens, the Cliff Adams singers were so much better than the whole top 40... Sing something simple........................................... For those that weren't there in the mid 80s, Radio 1 did not have its own FM network, but once a week, for 2 hours at 5:00 iirc the Radio 1 Top 40 took over Radio 2 (the height of un coolness)'s transmitters. The Cliff Addams singers came on at 4:30, in gloriously warm rich intimate unprocessed sound, a real treat for the young audiophile's ears.
  12. The "crack" could well be a ground loop. For the whining the solution for me is to turn the volume down on the power amp and turn up the pre. I am electronic engineer. This is all visible with test equipment.
  13. I have interesting mains. My office used to be the kitchen, and is also the mains distribution center for the house, It has 3 large fuse boxes, this is not absolute but since I joined some equipment across from one side of the room to the other, I get a noticeable "crack" sound from my speakers, occasionally, It is probably a fridge / freezer turning on or something like that. Didn't happen when it was all on one side of the room, so I suspect I have at least 2 different circuits. From this experience, a dedicated spur would make sense, or at least running everything from one circuit, with closely spaced sockets, you probably are already. Also there are noises on my mains, that seem fairly consistent, and I like to think it could be the pumping station just down the road. The result of this is the voltage fluctuates with a 2-3 second period, and also accompanied by an wining noise. This only causes problems to valve amplifiers in my experience, especially DHT, as the noise goes straight through the mains transformer into the valves. All these problems are audible, but I can get round them or ignore them. If you are not aware of auditable problems there probably aren't any.
  14. "The English may not like music, but they absolutely love the noise it makes" Thomas Beecham That sums me up pretty well.
  15. dave

    On the bench today.......

    After a couple of false starts I settled on 40w G9 bulb with ceramic base as it is smaller. The space is quite limited and even a little bayonet bulb was taller than the UL84, when including the base. It now has fixed biasing as well. The result of this is I have been able to wind back the standing current in the output valves, this in turn has increased the voltage across the UL84s , due to less current across the dropper resistor, from about 190 to 260. I am a bit wary of this but have seen at least one other EL86 valve running on 250 volt rails, so fingers crossed should be OK. This in turn has given me an increase in voltage swing, so I now get a little over 3 watts into 8 ohms from my 3 ohm output transformer. I have been wanting to try this, as I seem to have quite a few "vintage" 3 ohm output tranies around. The end result is the amp now draws about 41 watts rather than the previous 55, and I get more output power, and the amp as a whole runs a lot cooler, enough to put bottom cover on and right way up, rather than on its side with no base. Note directly heated monode to the right.