Quick update on Rc vs. Lc: After 30 hoirs of continuous operation and music: Well, its a bit of a sound machine. LC gives a fuller body, wood instruments have more wood, male voice are deeper etc. At the same time the fine nuances of a snare--drum where you can here each touch precisely is now with LC something in the backround. You definetly loose high frequency energy and resolution and win a very natural, mid-orientated presentation.
So no clear winner currently. I let the amorphous core burn in further and will prpare the amp for easy changing of capacitors to see what is the best possible setup...and once completed, I will implement a transformer coupling...or Ale's gyrator boards ?
What I found over improving my system: the sound overall becomes more transparent and precise, but at times as well a bit stiff and dry. Any hints what to try on that front ? paper in oil caps (right now I am using dry polyprops everywhere, Mundorf tubecaps)? Smaller and better caps in the heater raw supply (Currently 33000x2 Epkos/Sikorel...changing towards Silmic 3300*2) ? Or is it just time to get rid of the e182cc/El34-combo ?
So no clear winner currently. I let the amorphous core burn in further and will prpare the amp for easy changing of capacitors to see what is the best possible setup...and once completed, I will implement a transformer coupling...or Ale's gyrator boards ?
What I found over improving my system: the sound overall becomes more transparent and precise, but at times as well a bit stiff and dry. Any hints what to try on that front ? paper in oil caps (right now I am using dry polyprops everywhere, Mundorf tubecaps)? Smaller and better caps in the heater raw supply (Currently 33000x2 Epkos/Sikorel...changing towards Silmic 3300*2) ? Or is it just time to get rid of the e182cc/El34-combo ?
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You cannot compare Rc and Lc by generalizing that all "R"'s and "L"'s are the same, not to name C's!
With all respect, but Hammond IT's are entry level quality wise; astonishing that you guys strive for improved sound by things like tube rolling, and taking the influence of (IMO) the "iron" for granted
Isn't the quality of (output) transformers in tube amplifiers most important??It would make much more sense to compare dedicated anode chokes (think of what core material, winding technique and DCR does) before comparing with other interstage coupling methods.
Just my opinion
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The 126C isn't entry level when you use 2 in series as plate chokes. Just happens to work, though I take your point that in general Hammond OPTs aren't something we'd seriously choose. Yes, absolutely the quality of the transformers is crucial. I have an amorphous OPT and would also consider a more specialised plate choke for my driver stage, something like 15mA and 150H or more with as low a DC resistance as possible. I'm sure this is something you'd know how to build well.
Hi Pieter,
I am using dedicated Anode chokes by Lundahl LL1668 with amorphous core and Duelund Cast PIO Copper Caps. I would not call this entry level quality. I selected this as I wanted to understand what conceptually it can do for me and even though it costs a lot to exactly avoid the mistake you described. But still, something is missing in this combo. I have a lot of caps in my inventory I could try, but I have some doubts that the caps are the issue as with RC loading they let the information through.
Nevertheless, I have as well some Monolith IT with amorpous Ciore waiting to get their chance and those guys are typically praised high as well...lets see. And this is not about Lundahl bashing: My LL1692am are working in the line stage with the 4p1l wonderful transparent.
Intersting comment by Frentec that you feel the 4p1l has a bit of a hard sound...I do hear now a bit of a hard sound as well after tuning the system to so much transparency, but not yet sure from where it comes...that is why I asked Andy about a comparison towards 10y or other DhT...
Best Regards
I am using dedicated Anode chokes by Lundahl LL1668 with amorphous core and Duelund Cast PIO Copper Caps. I would not call this entry level quality. I selected this as I wanted to understand what conceptually it can do for me and even though it costs a lot to exactly avoid the mistake you described. But still, something is missing in this combo. I have a lot of caps in my inventory I could try, but I have some doubts that the caps are the issue as with RC loading they let the information through.
Nevertheless, I have as well some Monolith IT with amorpous Ciore waiting to get their chance and those guys are typically praised high as well...lets see. And this is not about Lundahl bashing: My LL1692am are working in the line stage with the 4p1l wonderful transparent.
Intersting comment by Frentec that you feel the 4p1l has a bit of a hard sound...I do hear now a bit of a hard sound as well after tuning the system to so much transparency, but not yet sure from where it comes...that is why I asked Andy about a comparison towards 10y or other DhT...
Best Regards
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I used the word hard loosely, the 4P1L sounds a touch hard in comparison to 01a, which is just so big & open sounding without any sign of strain, Dueland are too expensive for me too use, I do like depth though & some Caps just sound wide with no depth which makes you feel like you're listening to a sheet of paper.
Hi Blitz,
I agree with Pieter, what he implied was that during comparison of setup, a casual mention of LC and RC is rather frustrating for us and prevent further analysis. We and other members can benefit and have better interaction when at the very least specific L, R and C used, the more specific the better, and the bias point (plate voltage and current) of each setup during comparison are clear. When a part is casually mentioned as L and nothing else, we tend to assume entry level with characteristics not available to the poster which was incorrect in your case.
I agree with Pieter, what he implied was that during comparison of setup, a casual mention of LC and RC is rather frustrating for us and prevent further analysis. We and other members can benefit and have better interaction when at the very least specific L, R and C used, the more specific the better, and the bias point (plate voltage and current) of each setup during comparison are clear. When a part is casually mentioned as L and nothing else, we tend to assume entry level with characteristics not available to the poster which was incorrect in your case.
Ok, I guess we clarified this now. I wrote above already as well I am using a LTP with a CCS of Kevin C., so the current (in case of the e182cc 18mA, in the case of the 4p1l 28mA) is held constant. Voltage 190V in case of the 4p1l and 145V in case of the e182cc. Voltage at the anode is held constant by using different taps on the main transformer and some dropper resistors before the actual LcRC filter.
I hope this was specific enough. And let's be clear: They simply do sound different and in a different way then I would have expected it. I love the full body and the substance of the choke, but I would hate to trade this in for less treble resolution/air.
But... 30hours of usages, some people say an amorphous core needs 100hours or more to burn in, so maybe I will get a positive surprise later still. The R of the Rc is a 8k2 Mills, 12Watt wirewound non-inductive.
Frentec, If you want a very similar result which will give both, Mundorf and Duelund Cast a tough time: Try Miflex KPCU1 for a fraction of the price. They are even bigger than Duelund Cast, look basically the same, are as well Copper, Paper in Oil...they have beaten the Duelund Cast in my speaker cross-over and Mundorf in some tube-amps of a friend of mine....Let them burn in with music for 24 hours before you judge them. And maybe you will get a big surprise...
I hope this was specific enough. And let's be clear: They simply do sound different and in a different way then I would have expected it. I love the full body and the substance of the choke, but I would hate to trade this in for less treble resolution/air.
But... 30hours of usages, some people say an amorphous core needs 100hours or more to burn in, so maybe I will get a positive surprise later still. The R of the Rc is a 8k2 Mills, 12Watt wirewound non-inductive.
Frentec, If you want a very similar result which will give both, Mundorf and Duelund Cast a tough time: Try Miflex KPCU1 for a fraction of the price. They are even bigger than Duelund Cast, look basically the same, are as well Copper, Paper in Oil...they have beaten the Duelund Cast in my speaker cross-over and Mundorf in some tube-amps of a friend of mine....Let them burn in with music for 24 hours before you judge them. And maybe you will get a big surprise...
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I think Frentec and I are very much on the same page here. I only use DHTs and for 3 stages the first two would be 01A followed by 2P29L, 4P1L or 10Y as drivers since they can take 15mA and up. I just have 2 stages so 2P29L into PSE 4P1L is my daily listen, but I regret not using the 01A.
I could certainly go better with the anode choke on the driver stage, but I don't know if amorphous is the answer. My OPT is amorphous and I want to put back some body and warmth into the sound, with as little sacrifice of detail as possible. With my O'Netics OPTs I get warmth and body but at the expense of some detail, so I could drive those with an amorphous plate choke maybe. I love the detail of amorphous but not 100% convinced about the sound overall.
I've tried the Lundahl LL1664 as OPT and the LL1660/18mA used as a plate choke and what I find is good but not great detail, but also a slight hardness in the sound. They don't have a warm, fluid sound like I get with O'Netics for instance, or even the humble 126C. They don't quite "let go". The answer may be Monolith or one of the Japanese makers like Hashimoto but that means spending money without knowing the consequences in advance. With high quality iron like this some spending is inevitable, and this also involves decisions about nickel or amorphous cores or nanocrystal technology. And then there's the winding skill involved and what gap to use.
As for coupling caps I still use FT-2 or FT-3 since I like teflon for its neutrality and detail. Maybe paper in oil would put some warmth back but I never got on with the sound in the ones I tried.
As for chokes in the filament supply I'm not fussy - more Henries the better. Not sure if the quality of the choke matters there.
Have you tried the 01A with double 126C? You can add Ale's follower board later easily enough.
3mA isn't enough for a driver stage, it needs more into PSE 4P1L in filament bias. I've tried the 01A in a few different ways. Ale's follower board may be a solution and it works for him, but right now I'm trying to find solutions using a plate choke rather than solid state. Trying to push this as far as it can go because although gyrators and followers get you quickly and cheaply to a high level of performance, and Ale's are no doubt as good as anything out there, there can be an extra smoothness with really good iron. I've always liked plate chokes.
Andy, I feel a lot like you...I tried for the preamp as well shunt regs with transistor ccs and transistor shunt reg/OD3 Vr tube shunt reg, both. I can hear if there is a transistor in your power supply. Simple LcLC withextremely well made chokes was more life-like.
Here is a good read on the matter of anode chokes and maybe a solution to get both, body/tone and transparency: audiofilterchokes-page3
Especially this schematic is worthwhile, so it is not only LC vs. RC...there is a third option LRC...
I will test this...very easy to do in my setup.
"The only problem of using just the CT choke is bandwidth. To avoid the shunt C and shunt L effects of the choke used in a differential amp, or Long Tail Pair, LTP, I place a resistance between the ends of the choke winding and each anode, usually at least 2 x Ra. Fig 1 below shows the set up with 8k2. Thus the triodes' lowest load value possible is 8k2 which is 3.7 x Ra for 1 x EL84 in triode. Phase shift caused by shunt C and shunt L is virtually eliminated..."
Here is a good read on the matter of anode chokes and maybe a solution to get both, body/tone and transparency: audiofilterchokes-page3
Especially this schematic is worthwhile, so it is not only LC vs. RC...there is a third option LRC...
I will test this...very easy to do in my setup.
"The only problem of using just the CT choke is bandwidth. To avoid the shunt C and shunt L effects of the choke used in a differential amp, or Long Tail Pair, LTP, I place a resistance between the ends of the choke winding and each anode, usually at least 2 x Ra. Fig 1 below shows the set up with 8k2. Thus the triodes' lowest load value possible is 8k2 which is 3.7 x Ra for 1 x EL84 in triode. Phase shift caused by shunt C and shunt L is virtually eliminated..."
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Yes Andy, it would not have the stone with RC. But has a good chance (on paper) to be good enough with LC coupling if not pushed really hard. Unlike resistor, an inductor is an energy storage element. I wonder, Isamu Asano can use 0.43ma and Shishido 1ma driver bias to drive a 2A3 on Loftin White direct couple topology.
I'll have to try again then - don't think I tried the 01A with 2 x 126C. Wasn't that good as a driver stage with 2 x 156C in series, good treble but light on bass. Massive DCR as well. 01A would be really nice if I can find a way to use it. I get enough body and dynamics with the 2P29L at 15mA so at least that represents a solution. It's a handy tube to have about for projects.
??? Pieter, This is a link (put your mouse above the graphic and look to you status bar of the browser, you will see it points to Patrick's page). I am not aware that you can paste any graphics here.
You can tell the forum to show the schematics so that others have less work to find it. Not sure what you your point is...especially as I have provide the original source/link, so that Patrick gets all the click and credits.
You can tell the forum to show the schematics so that others have less work to find it. Not sure what you your point is...especially as I have provide the original source/link, so that Patrick gets all the click and credits.
Andy & Frank,
I couldn't get the 2p29L to work for me, I had too much microphonics going on, more than 4P1L, not sure why though, I was running it into Gyrator, using 100nf on Board 220nf to couple, I know Ale used 470uf here, but the thing was howling like hell, tried 2 pairs of valves, same PS was used from 4P1L (as set up from PSUD2) CLCLC for screen mode of 4P1L, I thought I might be doing something wrong, but as both were run at 15mA, it's not likely to be that, all Parameters were changed on the filament side, Voltages were very well balanced channel to channel as well(within 0.7V).