Stephe,
Don’t know if you have tried Lundahl, they do have a distributor in the US, Erhard Audio. Of course,the iron is custom ordered and shipping would be from Sweden, although he probably orders batches in bulk so a savings may be made.
Best,
Anand.
Don’t know if you have tried Lundahl, they do have a distributor in the US, Erhard Audio. Of course,the iron is custom ordered and shipping would be from Sweden, although he probably orders batches in bulk so a savings may be made.
Best,
Anand.
Hmm they are located in Europe and they price their items in Euros, how dare them!!!
I haven't, but the way they package their iron, I'd have to change how I fab up my amps. I should still give them a more serious look, thanks for the tip.
Stephe -
The point I was trying to make is not that Thermionic have the effrontery to charge in Euros, but the fact that they charge in Euros means they are located in Europe, and their iron has to make its way from Europe all the way across the continental USA to me on the West Coast - that won't be cheap. I checked out the prices on their transformers, and they aren't precisely bargain basement, either...
I prefer to scrounge my output iron from sources here in the US. I've gotten some pretty good bargains on E-pray, and from people like Edcor and Musical Power Supplies, as well as from the swap meet here. However, Edcor has really jacked up their prices as of late - maybe they are getting hit with hideous price increases on their basic materials. Heyboer has been mentioned by some as a good source for quality output iron
The point I was trying to make is not that Thermionic have the effrontery to charge in Euros, but the fact that they charge in Euros means they are located in Europe, and their iron has to make its way from Europe all the way across the continental USA to me on the West Coast - that won't be cheap. I checked out the prices on their transformers, and they aren't precisely bargain basement, either...
I prefer to scrounge my output iron from sources here in the US. I've gotten some pretty good bargains on E-pray, and from people like Edcor and Musical Power Supplies, as well as from the swap meet here. However, Edcor has really jacked up their prices as of late - maybe they are getting hit with hideous price increases on their basic materials. Heyboer has been mentioned by some as a good source for quality output iron
That's not strange because it depends on the distributed capacitance which is likely different for the two secondaries (even if it's tapped secondary for 4-8-16).
-3 dB @22KHz is rather poor for that kind of transformer but it might be acceptable for some. For higher impedance models it was worse and copper resistance was very high. That's my experience. The new models are definitely more balanced design without exaggerations.
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You need to look at the net cost which is shown is smaller characters. The normal cost shown includes the 23% VAT that you don't have in the US.
Take the 1.5K transformer, for example, and compare it to your 1640:
https://sklep.toroidy.pl/en_US/p/TTG-KT88PSE-Tube-output-UL-transformer-1,5kOhm-KT88-300B-PSE/589
It will cost $120 for you. Then only need to add tax (if any) and shipping.
Plus shipping.
I ordered some Toroidy P-P OTs thru the distributor TME.EU a couple of years ago, and TME had very discounted shipping. But I don't see Toroidy audio parts listed there anymore.
One thing bugs me about their new CFB P-P toroidals, they all seem to have the same primary according to the Toroidy stats. Seems like that would run out of voltage headroom for the higher Z OTs ? I can only surmise fewer turns on the secondary for higher Zprimary ? Normally one expects the secondary to stay the same (for same core size) and the primary turns to increase for higher Zprimary. (all same 80 Watts)
I ordered some Toroidy P-P OTs thru the distributor TME.EU a couple of years ago, and TME had very discounted shipping. But I don't see Toroidy audio parts listed there anymore.
One thing bugs me about their new CFB P-P toroidals, they all seem to have the same primary according to the Toroidy stats. Seems like that would run out of voltage headroom for the higher Z OTs ? I can only surmise fewer turns on the secondary for higher Zprimary ? Normally one expects the secondary to stay the same (for same core size) and the primary turns to increase for higher Zprimary. (all same 80 Watts)
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There is always the option of parafeed. A couple of hammond 194e chokes in series would work very well for a 5K load. Then it becomes a game of finding a decent 5K push pull transformer as your output. You could even try to get tricky and use a power transformer as your output.
I hesitate to mention this, especially for SE audiophiles, but there is the Xfmr cheat patent US4614914 by Audio Precision. Which eliminates Xfmr distortion.
Just takes a few resistors, extremely clever. However:
Previous experience with the "Anti-Triode" scheme (many years ago) for SE results using a P-P OT with Triode and "antitriode" (with double the power and solid Bass) gave disappointing listener results. There was nothing wrong with the scheme, it just proved that SE magic is all about 2nd H tube distortion and 3rd H Xfmr distortion, which got -removed- by the scheme! There was no crossover distortion due to it being class A. (proving the common SE idiom phony)
So the cheat patent will give you OTL results with just one or two tubes and -full power- (not 10% OTL efficiency) , delivering what SE promises but doesn't actually deliver.
Can you live with that?
(using a P-P OT with a current source on one side will give similar results as "Anti Triode", but not doubled power or reduced 2nd H.)
Just takes a few resistors, extremely clever. However:
Previous experience with the "Anti-Triode" scheme (many years ago) for SE results using a P-P OT with Triode and "antitriode" (with double the power and solid Bass) gave disappointing listener results. There was nothing wrong with the scheme, it just proved that SE magic is all about 2nd H tube distortion and 3rd H Xfmr distortion, which got -removed- by the scheme! There was no crossover distortion due to it being class A. (proving the common SE idiom phony)
So the cheat patent will give you OTL results with just one or two tubes and -full power- (not 10% OTL efficiency) , delivering what SE promises but doesn't actually deliver.
Can you live with that?
(using a P-P OT with a current source on one side will give similar results as "Anti Triode", but not doubled power or reduced 2nd H.)
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I. Generalizations of Both single ended and push pull amplifiers that do not have negative feedback:
Single Ended Amplifiers:
Everybody remembers the fact that most single ended amplifiers have dominant 2nd Harmonic Distortion.
And, that when the amplifier is only putting out a small portion of its maximum output power, Distortion is at a Very Low percent (%).
But what is too often forgotten about single ended amplifiers is their Damping Factor Characteristics:
A. When the amplifier is only putting out a small portion of its maximum output power, The Damping Factor often is Medium, and is Symmetrical.
B. When the amplifier is putting out its maximum output power, The Damping Factor often is Low, and is Very Un-Symmetrical.
So,
Think about how the loudspeaker woofer responds to the amplifier's Symmetrical Damping Factor (A.),
and then how the loudspeaker woofer responds to the amplifier's Un-Symmetrical Damping Factor (B.).
Symmetrical Damping Factor at low power levels (Class A), but Un-Symmetrical Damping Factor at high power levels (Class A, single ended must stay in Class A, or the music sounds very bad because of the clipping).
Push Pull Amplifiers:
Everybody remembers the fact that most push pull amplifiers have dominant 3rd Harmonic Distortion.
And, that when the amplifier is only putting out a small portion of its maximum output power, Distortion is at a Very Low percent (%).
What is too often forgotten about push pull amplifiers is their Damping Factor Characteristics:
A. When the amplifier is only putting out a small portion of its maximum output power, The Damping Factor often is Medium, and is Symmetrical.
B. When the amplifier is putting out its maximum output power, The Damping Factor often is Medium, and is Symmetrical.
So,
Think about how the loudspeaker woofer responds to the amplifier's Symmetrical Damping Factor (A.),
and then how the loudspeaker woofer responds to the amplifier's Symmetrical Damping Factor (B.).
Symmetrical Damping Factor at all power levels (Class A).
I. Generalizations of Both single ended and push pull amplifiers that Do have Global negative feedback:
Single ended and push pull . . .
Global Negative Feedback will change the characteristics of the amplifier . . .
Reduces Both the 2nd Harmonic Distortion and 3rd Harmonic Distortion percent (%) at Both low power level out, and high power out.
I Increases the Damping Factor at Both low power out, and high power out.
I makes the Damping Factor Symmetrical, at Both low power out, and high power out.
III. When it comes to the sound of an amplifier plus a loudspeaker, nothing is as simple as it seems, when all those "Rules" often fall apart, and you overlook or forget some of those "Rules" . . .
When you put a recording on and Listen to the results of the amplifier and loudspeaker as a System, do not be surprised.
Try and predict what you will hear before you turn the system on; when you use different amplifiers, and different loudspeakers, and how they work, or do not work well together . . .
Either Positive Synergy Or Negative Synergy.
Have Fun!
Single Ended Amplifiers:
Everybody remembers the fact that most single ended amplifiers have dominant 2nd Harmonic Distortion.
And, that when the amplifier is only putting out a small portion of its maximum output power, Distortion is at a Very Low percent (%).
But what is too often forgotten about single ended amplifiers is their Damping Factor Characteristics:
A. When the amplifier is only putting out a small portion of its maximum output power, The Damping Factor often is Medium, and is Symmetrical.
B. When the amplifier is putting out its maximum output power, The Damping Factor often is Low, and is Very Un-Symmetrical.
So,
Think about how the loudspeaker woofer responds to the amplifier's Symmetrical Damping Factor (A.),
and then how the loudspeaker woofer responds to the amplifier's Un-Symmetrical Damping Factor (B.).
Symmetrical Damping Factor at low power levels (Class A), but Un-Symmetrical Damping Factor at high power levels (Class A, single ended must stay in Class A, or the music sounds very bad because of the clipping).
Push Pull Amplifiers:
Everybody remembers the fact that most push pull amplifiers have dominant 3rd Harmonic Distortion.
And, that when the amplifier is only putting out a small portion of its maximum output power, Distortion is at a Very Low percent (%).
What is too often forgotten about push pull amplifiers is their Damping Factor Characteristics:
A. When the amplifier is only putting out a small portion of its maximum output power, The Damping Factor often is Medium, and is Symmetrical.
B. When the amplifier is putting out its maximum output power, The Damping Factor often is Medium, and is Symmetrical.
So,
Think about how the loudspeaker woofer responds to the amplifier's Symmetrical Damping Factor (A.),
and then how the loudspeaker woofer responds to the amplifier's Symmetrical Damping Factor (B.).
Symmetrical Damping Factor at all power levels (Class A).
I. Generalizations of Both single ended and push pull amplifiers that Do have Global negative feedback:
Single ended and push pull . . .
Global Negative Feedback will change the characteristics of the amplifier . . .
Reduces Both the 2nd Harmonic Distortion and 3rd Harmonic Distortion percent (%) at Both low power level out, and high power out.
I Increases the Damping Factor at Both low power out, and high power out.
I makes the Damping Factor Symmetrical, at Both low power out, and high power out.
III. When it comes to the sound of an amplifier plus a loudspeaker, nothing is as simple as it seems, when all those "Rules" often fall apart, and you overlook or forget some of those "Rules" . . .
When you put a recording on and Listen to the results of the amplifier and loudspeaker as a System, do not be surprised.
Try and predict what you will hear before you turn the system on; when you use different amplifiers, and different loudspeakers, and how they work, or do not work well together . . .
Either Positive Synergy Or Negative Synergy.
Have Fun!
Once you start putting N Fdbk into these various schemes, they all start trending toward the -same- sound.
I suggest starting with a scheme that gives pleasant or at least acceptable sound with low Fdbk, and a knob to adjust the amount of N Fdbk to suit one's sensibility for the music type.
For speakers, I guess one can always go for those electrostats, if you don't mind your kids or pets getting zapped.
Well, the other factor is what kind of tube to use. Looking at JJ KT77 curves, look pretty good. Looking at KT88 curves, yuk! There as bad as some TV Sweeps! Not to diss. all TV Sweeps. 10JA5, 6LU8/6LR8, EL506 curves look pretty good. Local N Fdbk to the rescue for many other Sweeps.
I suggest starting with a scheme that gives pleasant or at least acceptable sound with low Fdbk, and a knob to adjust the amount of N Fdbk to suit one's sensibility for the music type.
For speakers, I guess one can always go for those electrostats, if you don't mind your kids or pets getting zapped.
Well, the other factor is what kind of tube to use. Looking at JJ KT77 curves, look pretty good. Looking at KT88 curves, yuk! There as bad as some TV Sweeps! Not to diss. all TV Sweeps. 10JA5, 6LU8/6LR8, EL506 curves look pretty good. Local N Fdbk to the rescue for many other Sweeps.
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smoking-amp,
Tying an Unknown amplifier output terminals; to an electrostatic speaker that consists of a step-up transformer that has inductance, capacitance, leakage inductance, etc.; to the highly capacitive vibrating film membrane . .
May bring Unknown results.
Even given that, over many many decades I have heard very nice sounds coming from many different manufacturer's electrostatic speakers.
Question about Electrostatic speakers:
When a large bass note is played, and a flute at the same time, how much does the relatively large membrane excursion change the capacitance from the membrane to the stators?
Reminds me of the changing capacitance versus voltage for JFETs, MOSFETs, NPNs, and PNPs.
My KT77s performed better than my EL34s in the same amplifier (even though they have specifications that are extremely similar).
Beam Power 'Kinkless "Tetrode"', versus Pentode?
Tying an Unknown amplifier output terminals; to an electrostatic speaker that consists of a step-up transformer that has inductance, capacitance, leakage inductance, etc.; to the highly capacitive vibrating film membrane . .
May bring Unknown results.
Even given that, over many many decades I have heard very nice sounds coming from many different manufacturer's electrostatic speakers.
Question about Electrostatic speakers:
When a large bass note is played, and a flute at the same time, how much does the relatively large membrane excursion change the capacitance from the membrane to the stators?
Reminds me of the changing capacitance versus voltage for JFETs, MOSFETs, NPNs, and PNPs.
My KT77s performed better than my EL34s in the same amplifier (even though they have specifications that are extremely similar).
Beam Power 'Kinkless "Tetrode"', versus Pentode?
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KT77 triode mode curves are noticeably better than EL34 triode mode curves at the HV end. Likely part of the difference.
An interesting comparison occurs between 6GE5 and 10JA5 tubes. From the same manufacturer (Sylvania in this case), the internals look the same. On dissecting both, the internals were virtually identical, -EXCEPT- for one thing. The 6GE5 (and probably most TV Sweeps ) had flat grid 1 wires above a flat cathode. The 10JA5 had slightly bulged grid wires (slightly bulged away in the center from the cathode) above a flat cathode.
If you compare the plate curves, the 6GE5 has the typical square law spacing of Sweeps, with nearly straight lines extending to higher voltage above fairly sharp knees. ( 21LG6A is the ultimate case here, with very low screen current)
In contrast, the 10JA5 has much more evenly spaced curves and more rounded knees. 10JA5 is spec'd for TV vertical amplifier service, so needed to be pretty linear. 6GE5 was spec'd as a horizontal sweep, so is a good SWITCH 😵. (although not TOO bad for linear use, as proven by many DIY audio Amps using 6JN6 with some local N Fdbk. same tube)
I suspect the 10JA5 makes use of carefully controlled screen current from mis-aligned beam focusing to get linearity. Comparing these two tubes in triode mode, however, the 6GE5 has the better triode curves. The 38HE7 beam pentode is an odd exemplar here, a fairly linear horiz. sweep with really good triode curves too. The 12HL7 (10 Watt high gm frame grid video amp tube) is another oddball. A Linear pentode and very linear in triode. Magic design techniques, I haven't figured that one out yet.
An interesting comparison occurs between 6GE5 and 10JA5 tubes. From the same manufacturer (Sylvania in this case), the internals look the same. On dissecting both, the internals were virtually identical, -EXCEPT- for one thing. The 6GE5 (and probably most TV Sweeps ) had flat grid 1 wires above a flat cathode. The 10JA5 had slightly bulged grid wires (slightly bulged away in the center from the cathode) above a flat cathode.
If you compare the plate curves, the 6GE5 has the typical square law spacing of Sweeps, with nearly straight lines extending to higher voltage above fairly sharp knees. ( 21LG6A is the ultimate case here, with very low screen current)
In contrast, the 10JA5 has much more evenly spaced curves and more rounded knees. 10JA5 is spec'd for TV vertical amplifier service, so needed to be pretty linear. 6GE5 was spec'd as a horizontal sweep, so is a good SWITCH 😵. (although not TOO bad for linear use, as proven by many DIY audio Amps using 6JN6 with some local N Fdbk. same tube)
I suspect the 10JA5 makes use of carefully controlled screen current from mis-aligned beam focusing to get linearity. Comparing these two tubes in triode mode, however, the 6GE5 has the better triode curves. The 38HE7 beam pentode is an odd exemplar here, a fairly linear horiz. sweep with really good triode curves too. The 12HL7 (10 Watt high gm frame grid video amp tube) is another oddball. A Linear pentode and very linear in triode. Magic design techniques, I haven't figured that one out yet.
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Matt at MPS stacked pairs of his regular 10W and 20W SE transformers for parafeed at no charge. Very reasonable I thought. I have the 10W versions in a 6V6 SE parafeed amp and I think it sounds really great for only 3-4 watts. At 1W it measures -3dB at 15Hz and 65kHz.