Search found 36 matches

by shinebox
Sat Sep 10, 2011 6:08 pm
Forum: Transformers
Topic: dave: have transformers still. ? on new ones
Replies: 3
Views: 4154

The tagline for this spam (purportedly from an essay writing service, no less - not that I dared click on the link) is so brilliant that I vote we keep it...
by shinebox
Mon Oct 11, 2010 5:46 pm
Forum: sbench 101
Topic: I'm still alive
Replies: 5
Views: 5845

Good on you Stephie and best wishes for a speedy recovery,
shines
by shinebox
Sat Oct 09, 2010 1:55 pm
Forum: Transformers
Topic: A midbass transformers with fast core
Replies: 13
Views: 11637

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...
by shinebox
Sun Feb 28, 2010 9:12 pm
Forum: Sim City
Topic: 13E1 triode model
Replies: 1
Views: 3397

Thanks Dr D, very appreciated... will see how they compare to the published Ia vs Vg curves on the datasheet...

cheers
by shinebox
Wed Feb 10, 2010 9:22 am
Forum: Phono
Topic: Pentode Phono
Replies: 24
Views: 46933

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 ...
by shinebox
Tue Feb 09, 2010 9:51 am
Forum: Phono
Topic: Pentode Phono
Replies: 24
Views: 46933

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...
by shinebox
Mon Feb 08, 2010 11:10 am
Forum: Phono
Topic: Pentode Phono
Replies: 24
Views: 46933

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...
by shinebox
Sun Feb 07, 2010 10:49 pm
Forum: Phono
Topic: Pentode Phono
Replies: 24
Views: 46933

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 ...
by shinebox
Wed Nov 25, 2009 8:31 pm
Forum: Phono
Topic: SUT Loading and Phase
Replies: 19
Views: 15727

(slaps head) Many many years ago I sim'd an SE output stage deliberately playing with the cathode bypass cap (to introduce an LF resonance) and variable damping thereof to "extend" the LF response. Whilst I could get it reasonably flat, I didn't like what the phase was doing. Similar argum...
by shinebox
Thu Aug 06, 2009 11:38 am
Forum: Attenuators
Topic: boxed up autoformer
Replies: 6
Views: 5893

Very cool!

Seeing it brought back a childhood memory, when I dreamed of having a car that was a bit battered, rusty and unsporty looking but was souped up such that it could see off ferraris and the like at traffic lights....

Just need some matching amps now....
by shinebox
Sun Aug 02, 2009 7:31 pm
Forum: Transformers
Topic: Mains transformer
Replies: 1
Views: 6063

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...
by shinebox
Fri May 29, 2009 9:48 pm
Forum: Transformers
Topic: 3Khz to 12Khz 80% nickel output transformer.
Replies: 10
Views: 15674

Hi Dave,
My lams were singing noticeably with music playing. But such glorious music...
Cheers
by shinebox
Fri May 29, 2009 11:21 am
Forum: Transformers
Topic: 3Khz to 12Khz 80% nickel output transformer.
Replies: 10
Views: 15674

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 ...
by shinebox
Sat Dec 20, 2008 2:05 am
Forum: Phono
Topic: Transformer phono correction
Replies: 54
Views: 45438

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...
by shinebox
Thu Sep 25, 2008 2:06 am
Forum: Attenuators
Topic: Balanced autoformer?
Replies: 6
Views: 6330

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...
by shinebox
Fri Feb 02, 2007 9:01 pm
Forum: Transformers
Topic: SE amps to drive ES panels.
Replies: 20
Views: 26362

Allo Is it not just the ellptical loadline presented by the ESLs? PP better able to deal with that? Look at an ESL's capacitive loadline on SE and you quickly see you want to drive a higher impedance than usual to minimise current variation (the "width" of the ellipse)... But then, that's ...
by shinebox
Fri Jan 26, 2007 2:50 am
Forum: Transformers
Topic: SE amps to drive ES panels.
Replies: 20
Views: 26362

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...
by shinebox
Fri May 12, 2006 9:09 pm
Forum: Transformers
Topic: Balanced interstages for PP
Replies: 16
Views: 15601

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...
by shinebox
Sat Apr 22, 2006 6:42 pm
Forum: Transformers
Topic: Balanced interstages for PP
Replies: 16
Views: 15601

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...
by shinebox
Wed Apr 19, 2006 3:51 pm
Forum: Transformers
Topic: Balanced interstages for PP
Replies: 16
Views: 15601

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...
by shinebox
Tue Apr 18, 2006 12:26 pm
Forum: Transformers
Topic: Balanced interstages for PP
Replies: 16
Views: 15601

(that was me)

moved from the AVC forum where I mistakenly posted before...
Sorry about that
by shinebox
Thu Nov 17, 2005 12:34 pm
Forum: Pb Place
Topic: Power transformers
Replies: 6
Views: 9548

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...
by shinebox
Sat Nov 05, 2005 1:19 am
Forum: Inductors
Topic: Ed's grid chokes
Replies: 8
Views: 12809

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...
by shinebox
Wed Sep 14, 2005 8:09 pm
Forum: Transformers
Topic: Ultimate bandlimited SE 801A transformer
Replies: 21
Views: 24117

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...
by shinebox
Tue Sep 13, 2005 2:04 pm
Forum: Transformers
Topic: Ultimate bandlimited SE 801A transformer
Replies: 21
Views: 24117

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...
by shinebox
Wed Sep 07, 2005 1:11 pm
Forum: Transformers
Topic: Ultimate bandlimited SE 801A transformer
Replies: 21
Views: 24117

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 ...
by shinebox
Sun Jul 24, 2005 9:01 am
Forum: Transformers
Topic: New to Forum, Throwing Out Some Thoughts
Replies: 35
Views: 50891

Hey DC,

It was me who measured zero bias as a way of circumventing the biasing conundrum (not to mention reducing noise etc). Different conversation, ie shines going off on a tangent as usual...

Long time, hope all's well with you.

Best,
Chris
by shinebox
Fri Jul 22, 2005 7:23 am
Forum: Transformers
Topic: New to Forum, Throwing Out Some Thoughts
Replies: 35
Views: 50891

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...
by shinebox
Wed Jul 06, 2005 5:29 pm
Forum: Transformers
Topic: New to Forum, Throwing Out Some Thoughts
Replies: 35
Views: 50891

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...
by shinebox
Tue Jun 07, 2005 9:40 pm
Forum: Pb Place
Topic: Yorkshire Boatanchor event
Replies: 28
Views: 29186

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...