heres a link to a new amp designed for kt120 i spotted while browsing thru jac music.
LEVEN KT120 Verstärker Schaltbild. KT120 Amplifier schematics. Brought to you by JACMUSIC
anyone built it/ keen to be the first?
xianyang
LEVEN KT120 Verstärker Schaltbild. KT120 Amplifier schematics. Brought to you by JACMUSIC
anyone built it/ keen to be the first?
xianyang
In SE?
Any tube based on 6L6 design in SE can be used instead of my Variable Harmonizer. They are PP tubes. For SE were designed 6V6 and EL84, AFAIR.
Not to put too much of a fine point on it, but I've never considered any tube not designed solely for class B operation to be a "PP" tube. To me it is just a particular class of tube. I doubt 6V6 or 6BQ5 were designed with any more/any less consideration for SE operation than say the original 6L6G or even the 6550 as all have single tube class A1 operating parameters published in their data sheets in addition to class A1 and AB1 PP - this is not to say that some lend themselves better to SE operation than others, but whether or not this was a deliberate design goal is something I wonder about. Unfortunately in this country at least most of the guys who might know the actual answer to this question are probably dead at this point. The original 6L6G was designed at a time when most radios except for the very most expensive ones still used SE outputs.. Tubes like the 6Y6 and 6W6 might have been designed with a bias towards SE given their common application to small SE pentode amps, but even here I think they were probably more directly targeting a certain level of efficiency, cost, sensitivity, and power capability.
Ah I see, that is what you meant by the PP/SE tube remark, and it does make absolute sense in that context.. I always look at the curves, it's kind of the reason I have come to favor certain DHTs over other types.. The 6BQ5, 6V6, 6Y6 and EL34 (some anyway) do seem to perform nicely as triodes in SE.. (in some cases perhaps UL/Pentode too?)
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The only way round the KT120 grid leak problem is a radically redesigned LoZ slam driver or use a SS class A totem pole config and DC coupled = Miller problems solved overnight. Not really a difficult undertaking..stability issues carefully addressed. I suspect this is what EH had in mind for driving this monster in AB power HiFi but probably aimed at MI amps using part SS cum tubestage finals....... Class B would make a nice amount of power is it required ?
Regarding equipment design, I'm not using this tube.. On-stage redundancy is a problem nicely solved by others.
I'm suprised Eli finds the EH KT90 sounds flat...No problem by my ears...these can shake the building. By coincidence, over the winter, a parallel p-p 200+200W KT90 leviathan is gradually being assembled. The amp theory already done. It's the PSU that requires the protein.
Again, a conundrum arises verus sound quality and distortion. I'm getting lowest THD using EH KT90's with Sowter transformers than any other tube in it's class, even orig
KT88's........ No1 suspect item ? the o/p tranny quality and amount of NFB.
I'm all for a reprod 12BY7A; in all the 45 yrs using this tube, it has become my most favourite and outstanding performer but it likes a bit of current.
Again; on the output level, there is no sonic performance substitute to original
GE 6550A; this tube is in it's own element. Gold dust.
I agree with Trout. I'm finding SED KT88's have unpredictable behaving screens, tap'em hard en-route and THD rockets. Not a travelling tube.
richy
Regarding equipment design, I'm not using this tube.. On-stage redundancy is a problem nicely solved by others.
I'm suprised Eli finds the EH KT90 sounds flat...No problem by my ears...these can shake the building. By coincidence, over the winter, a parallel p-p 200+200W KT90 leviathan is gradually being assembled. The amp theory already done. It's the PSU that requires the protein.
Again, a conundrum arises verus sound quality and distortion. I'm getting lowest THD using EH KT90's with Sowter transformers than any other tube in it's class, even orig
KT88's........ No1 suspect item ? the o/p tranny quality and amount of NFB.
I'm all for a reprod 12BY7A; in all the 45 yrs using this tube, it has become my most favourite and outstanding performer but it likes a bit of current.
Again; on the output level, there is no sonic performance substitute to original
GE 6550A; this tube is in it's own element. Gold dust.
I agree with Trout. I'm finding SED KT88's have unpredictable behaving screens, tap'em hard en-route and THD rockets. Not a travelling tube.
richy
I always favor DC coupling to the output tube grid. Benefits include stability, overload recovery, frequency response, lower distortion, etc. Anyway I got my Quad and attached are the SOFIA curves. I was VERY impressed by the stability and ruggedness right out of the box.
One of the very first SOFIA imported to the US; the extremely rare DOS version allows EACH parameter to be edited; no crappy libraries like the Lose-Dos 3.1 version.
One of the very first SOFIA imported to the US; the extremely rare DOS version allows EACH parameter to be edited; no crappy libraries like the Lose-Dos 3.1 version.
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help VTL75/75 KT90EI
Hello :in first time excuse me for my bad english..: I am new to this forum and are not an expert on tubes as many here: I have an VTL75/75 KT90Ei: after almost thirty years I begin to think about changing the tube... but I know with valves such as:I found only KT90 Electro Harmonix to replace KT90EI....but I do not know if they play well... and just want to understand if I can put on VTL75/75 other types of valves: the 6550 or KT88 or a new KT120 but I have no idea if these valves can work without problems such as voltage and current on this amp... I would like please a opinion on a good tube brand that sounds good and what kind of valve can be mounted: I like deep bass, but held back and listen mainly to jazz and fusion: With whom do you recommend, and greetings to everyone: thank's: freeman to Italy .
Hello :in first time excuse me for my bad english..: I am new to this forum and are not an expert on tubes as many here: I have an VTL75/75 KT90Ei: after almost thirty years I begin to think about changing the tube... but I know with valves such as:I found only KT90 Electro Harmonix to replace KT90EI....but I do not know if they play well... and just want to understand if I can put on VTL75/75 other types of valves: the 6550 or KT88 or a new KT120 but I have no idea if these valves can work without problems such as voltage and current on this amp... I would like please a opinion on a good tube brand that sounds good and what kind of valve can be mounted: I like deep bass, but held back and listen mainly to jazz and fusion: With whom do you recommend, and greetings to everyone: thank's: freeman to Italy .
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Mr. Dave,
Is there any chance that the software can export that data to a text file? It would be cool to read it into excel and manipulate there. I was planning on buying some KT120 as well.
Mostly the problem has to do with the legacy media and interfaces. That will daunt the effort, since likely several hours would be required to pull it off. Then one would have to format the data to CSV or TSV formatted ASCII; likely more time, but I could push that little task off to you; one of those keystroke macro programs would assist.
(BTW you sound like a youngster; I was LMFAO re 'export data' On DOS you have to do all that MANUALLY.)
(BTW you sound like a youngster; I was LMFAO re 'export data' On DOS you have to do all that MANUALLY.)
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I wasn't referring to DOS exporting the data, was more wondering if the Sofia software was capable of saving in and excel-friendly format.
I would be more than happy to re-format the data if you can capture it raw in some format. I am a digital electronics engineer/programmer so I am capable. In fact, I would just write a program to do it and share if you are interested.
After this next amp gets finished I was going to build a curve tracer of my own which would have no display. I would load test parameters on to an SD card, pop it and a tube into the tracer, then the tracer would make a .csv for viewing on the PC later. I would just like to be able to calculate the effects of feedback on the curves in excel.
sounds like a *FINE* endorsement for U-L operation, probably best with 40% tapping v. the lower implementation( the W6m OPT for instance, or perhaps BO-14 that can do 47% ). Fortunately I have a pair ov both...
cheers,
Douglas
Please contact VTL directly, they should be able to tell you. Not very many people here are likely to have VTL amps as we're mostly about designing and building our own.
Filament power would be one immediate issue why I would not do this without checking.
The SOFIA is Italian; I would have to see if the '.pte' files are in ASCII format. Since they are merely ADC readings it is likely that they are. However to transfer the files from the DOS lap top that is running the SOFIA requires floppy media and the purchase of a USB floppy drive to transfer to a modern computer.
BTW the KT120's did come up OK with the filament current limit at 2A. My amp is running a Baldwin organ transformer; usually readily available on our fave auction site for about $50. It slots right into an ST70 chassis and is as beefy as the 'tube stereo 120' power tranny. I am running the front end tubes using the 6V winding, and the power tubes are running off the 12V. There is also a 5V winding and the B+ is about 700VAC CT, so it runs at about 430-450 under load. I put a 50 ohm 20W resistor in series with the SS rectifier.
BTW the KT120's did come up OK with the filament current limit at 2A. My amp is running a Baldwin organ transformer; usually readily available on our fave auction site for about $50. It slots right into an ST70 chassis and is as beefy as the 'tube stereo 120' power tranny. I am running the front end tubes using the 6V winding, and the power tubes are running off the 12V. There is also a 5V winding and the B+ is about 700VAC CT, so it runs at about 430-450 under load. I put a 50 ohm 20W resistor in series with the SS rectifier.
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