Search found 36 matches
- Sat Sep 10, 2011 6:08 pm
- Forum: Transformers
- Topic: dave: have transformers still. ? on new ones
- Replies: 3
- Views: 4632
- Mon Oct 11, 2010 5:46 pm
- Forum: sbench 101
- Topic: I'm still alive
- Replies: 5
- Views: 7914
- Sat Oct 09, 2010 1:55 pm
- Forum: Transformers
- Topic: A midbass transformers with fast core
- Replies: 13
- Views: 14477
Yo shines here, CV pointed me in the direction of this thread... I think Romy meant 1kHz, not 1.000 Hz, so 2 decades... Romy - your actual Idc is 200-220mA, right? If you quote 350-400mA to Dave, I'd guess (only slightly kidding) you might end up with an airgap good for 1A... Similarly, are you real...
- Sun Feb 28, 2010 9:12 pm
- Forum: Sim City
- Topic: 13E1 triode model
- Replies: 1
- Views: 3709
- Wed Feb 10, 2010 9:22 am
- Forum: Phono
- Topic: Pentode Phono
- Replies: 24
- Views: 49954
Hey JJ, You mentioned causing trouble... I like to do that too. That should certainly work; I'd be curious about the noise at these levels, and actual dynamic shunt impedance of the VR tube may be comparable to that of the small cap at HF and affect the EQ... just guessing here. That's why I though ...
- Tue Feb 09, 2010 9:51 am
- Forum: Phono
- Topic: Pentode Phono
- Replies: 24
- Views: 49954
Hi all, Gotta say, the more I think about the pentode/shunt scheme, the more I like the idea. I have very little time this week to play, but just wanted to throw in some ideas for consideration: 1) Tube choice Input could also be E280F, and maybe worth investigating the Russian 6J52P... apparently a...
- Mon Feb 08, 2010 11:10 am
- Forum: Phono
- Topic: Pentode Phono
- Replies: 24
- Views: 49954
Hey Stephie, Keep talking all you want! I hear you regarding the current... I must keep remind myself how good a vertical loadline can look with a pentode at blistering currents. When I get a chance, I may try and sort out a sim with E55L (I think the US # is 8233)... that should be happy running at...
- Sun Feb 07, 2010 10:49 pm
- Forum: Phono
- Topic: Pentode Phono
- Replies: 24
- Views: 49954
Hiya, Funny you mention this - I was just helping my cabinet maker buddy put together a very simple phono stage using... D3a, Very interesting! May I ask why only shunt filtering? Less evil resistance in the filter path and strong drive for the output stage? I don't have a good feel for how optimal ...
- Wed Nov 25, 2009 8:31 pm
- Forum: Phono
- Topic: SUT Loading and Phase
- Replies: 19
- Views: 23034
- Thu Aug 06, 2009 11:38 am
- Forum: Attenuators
- Topic: boxed up autoformer
- Replies: 6
- Views: 6657
- Sun Aug 02, 2009 7:31 pm
- Forum: Transformers
- Topic: Mains transformer
- Replies: 1
- Views: 7514
Mains transformer
Allo This is just some food for thought - not sure if this has been discussed or mentioned before... The Chimera Labs guys hypothesised in Sound Practices that much of the sounds of rectifiers was caused by them exciting resonances in the mains transformer. Seemed solid to me, and they had a nice ar...
- Fri May 29, 2009 9:48 pm
- Forum: Transformers
- Topic: 3Khz to 12Khz 80% nickel output transformer.
- Replies: 10
- Views: 16659
- Fri May 29, 2009 11:21 am
- Forum: Transformers
- Topic: 3Khz to 12Khz 80% nickel output transformer.
- Replies: 10
- Views: 16659
big nickel
Allo Dave - Indeed I am listening, with great interest... Did you notice the lams singing along at all? That was a minor issue I had with my Sowter 80% opts (smaller core, different lams, different winder), yet the sound was much as you described. Romy - very much looking forward to your reports on ...
- Sat Dec 20, 2008 2:05 am
- Forum: Phono
- Topic: Transformer phono correction
- Replies: 54
- Views: 52567
Darned if I remember... I think the author was an influence on the Cat in his formative years... I suspect it may have been at GSC where I saw it too. I haven't actually read the article in years so I must revisit. My understanding of leakage inductance was that it was as much a function of the sect...
- Thu Sep 25, 2008 2:06 am
- Forum: Attenuators
- Topic: Balanced autoformer?
- Replies: 6
- Views: 6914
I wonder if it would work to replace the riaa with a series combo of paralleled LRs (ie the conjugate circuit) after the first coupling caps... These Ls could be tapped for volume control, but would need to be on identically wound separate cores (not coupled). Taps would go to second stage grids. St...
- Fri Feb 02, 2007 9:01 pm
- Forum: Transformers
- Topic: SE amps to drive ES panels.
- Replies: 20
- Views: 30941
- Fri Jan 26, 2007 2:50 am
- Forum: Transformers
- Topic: SE amps to drive ES panels.
- Replies: 20
- Views: 30941
Yo Dave, A subject close to my heart this... and uncanny how it matches my experience: A long time ago, Pieter T made me some 1 to (0.75+0.75) SE stepups to drive some ML CLS panels directly from SE. The ratio was determined on the basis of maximising voltage swing driving up to 3kHz (where the pane...
- Fri May 12, 2006 9:09 pm
- Forum: Transformers
- Topic: Balanced interstages for PP
- Replies: 16
- Views: 16975
Shinebox Express
Allo Nice timing - Shines just got to NYC... I have a wedding over the memorial day weekend and will be flying back to blighty on the Tue or Wed (30 or 31 May). Dave, which one of these best suits for a visit 1) I already have the 26th booked off, lunchtime/early afternoon visit? Alternatively I cou...
- Sat Apr 22, 2006 6:42 pm
- Forum: Transformers
- Topic: Balanced interstages for PP
- Replies: 16
- Views: 16975
Hey Dave, Thanks for the detailed reply; to answer some of your points: 1) I'm sure Jon could dial in some deliberate DC imbalance to see what the effect would be. 2) I'm sure he'd be well up for trying out 49% vs 80% and reporting back. I would love to take part in that, but it will depend on wheth...
- Wed Apr 19, 2006 3:51 pm
- Forum: Transformers
- Topic: Balanced interstages for PP
- Replies: 16
- Views: 16975
Thanks Dave; your thoughts were similar to mine - I've built some headroom into the figures, but I'm always bearing in mind that if we relax some of the requirements, we might be able to go to the 80% mumetal. Jon is biasing the 300Bs at about -50V each, so worst case A1 swing is 70Vrms or 100V peak...
- Tue Apr 18, 2006 12:26 pm
- Forum: Transformers
- Topic: Balanced interstages for PP
- Replies: 16
- Views: 16975
(that was me)
moved from the AVC forum where I mistakenly posted before...
Sorry about that
Sorry about that
- Thu Nov 17, 2005 12:34 pm
- Forum: Pb Place
- Topic: Power transformers
- Replies: 6
- Views: 11700
Allo Paul, Glad to hear things are getting sorted out. An air gap and more turns than needed to run the B lower are both mandatory for quality mains iron, as is an e-screen. Wish all these had occurred to me (the gap in particular) when I spec'd my monster mains tx a while ago... what was that about...
- Sat Nov 05, 2005 1:19 am
- Forum: Inductors
- Topic: Ed's grid chokes
- Replies: 8
- Views: 15227
Dave's 5k:8
Allo Ed, Nice writeup. With respect to Dr Clips' 5k OPTs - I heard them a while ago in NYC, chez-il, A/B'd vs Pieter's 5k OPTs in a 2A3. Pieter's were as impressive as you would expect, Dave's had the same stuff going on, but with a somewhat calmer presentation, less "obviously" present bu...
- Wed Sep 14, 2005 8:09 pm
- Forum: Transformers
- Topic: Ultimate bandlimited SE 801A transformer
- Replies: 21
- Views: 25763
Allo dave, thanks for all the info, *very* interesting. What with the exchange rate as it is, I don't puke at the thought of a $600 pair of cores. My sowter 80% nickels (for 300B etc) cost me nearly $400 but they sound absolutely wonderful. They also sing along like nuts, so I'm thinking let's try s...
- Tue Sep 13, 2005 2:04 pm
- Forum: Transformers
- Topic: Ultimate bandlimited SE 801A transformer
- Replies: 21
- Views: 25763
Thanks for the reply Dave. I figured the taps wouldn't be an issue at those frequencies. I heard the Gordon argument before, but I'm not sure I buy it fully (he also prefers M4 to Nickel which I find hard to fathom, but that's fair enough). I think if the amps are topologically similar that goes mos...
- Wed Sep 07, 2005 1:11 pm
- Forum: Transformers
- Topic: Ultimate bandlimited SE 801A transformer
- Replies: 21
- Views: 25763
Ultimate bandlimited SE 801A transformer
Dr Dave, What are your thoughts for an all-out device for the (dreaded high impedance) 10Y/801A? I'm thinking of the following: Op point: 500V - 600V, 40mA max 1) midbass channel 100Hz to 800 Hz 4W at 100Hz (will prob x/o 1st order at 150 or 200Hz) 10k pri, inductance required of 50 - 80H? 4 and 16 ...
- Sun Jul 24, 2005 9:01 am
- Forum: Transformers
- Topic: New to Forum, Throwing Out Some Thoughts
- Replies: 35
- Views: 54095
- Fri Jul 22, 2005 7:23 am
- Forum: Transformers
- Topic: New to Forum, Throwing Out Some Thoughts
- Replies: 35
- Views: 54095
phono scheme
Allo J, Something very similar is on my project list (around about #10 though...aargh). Couple thoughts: 1) I've never seen anyone use zero bias for the input stage with tubes and I'm wondering why; an MC will laugh at the impedances involved, MM should be fine too. So long as the dc grid current is...
- Wed Jul 06, 2005 5:29 pm
- Forum: Transformers
- Topic: New to Forum, Throwing Out Some Thoughts
- Replies: 35
- Views: 54095
75TL
Allo Lynn,
Just wondering - anywhere we can get more details on this 75TL amp?
Many thanks,
shines
PS As for a solid state buffer stage - well, a certain cat tried all sorts of stuff and the only thing he found that was truly transparent was sand, so may well be worth a try...
Just wondering - anywhere we can get more details on this 75TL amp?
Many thanks,
shines
PS As for a solid state buffer stage - well, a certain cat tried all sorts of stuff and the only thing he found that was truly transparent was sand, so may well be worth a try...
- Tue Jun 07, 2005 9:40 pm
- Forum: Pb Place
- Topic: Yorkshire Boatanchor event
- Replies: 28
- Views: 37909
guilty as charged...
Ooops... sorry Paul, didn't mean to do your head in so much! Good chatting to you even if you regrets it... Btw, I'm not remotely a mathematician... those guys (proper ones, at any rate) are far, far more scary. The air-core may have been an extreme idea; I've only managed to get mine running on the...