I just complete a KT150 SE amp and am thrilled with the results! It also takes the KT120 but the 150 sounds even better with more clarity and definition in the low end. Mids are smooth as are the highs. Imaging is fantastic in all directions. I’m using LED biasing on the input tube which can be anything from a 6DJ8 family to a Russian 6N6. I really like the 6N6 for its low end. The PS uses all film caps and is dual mono with an Antek toroid power transforder. It has separate windings for each channels HV and filament. Anyone else using the KT150 in a SE amp?
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I was going to use Electra-print but he went out of business very recently so I took a chance on some from HifiEquuis on AliExpress and was very pleasantly surprised with the quality and sound of the 30 watt 150ma SE units. They have UL taps so I made it switchable. Shipping cost half the price of the transformers but they got here in like 10 days. They sound fantastic from 20hz to over 20khz.
I put a dc block on the AC input to the amp after the power switch that cleaned up pops and noise when lights or the fridge turns on/off.
All the wire is silver plated copper with Teflon jacket mil spec. The RCAs and outputs are all silver plated as are the contacts on the triode/UL switches. Silver bearing solder is used throughout.
All resistors are audio grade from PRP, TKD, and Mills. Caps are Clarity Caps. The volume control is Alps.
wiring is all point to point using an IAG terminal board i retrofitted with 8 pin sockets for the output tubes.
Rectification is FWBs using IXYS FRED diodes. Each channel has its own bridge and PS caps which are all poly film caps.
within reason everything is overbuilt to last.
Did I mention it sounds great too? Lol
I put a dc block on the AC input to the amp after the power switch that cleaned up pops and noise when lights or the fridge turns on/off.
All the wire is silver plated copper with Teflon jacket mil spec. The RCAs and outputs are all silver plated as are the contacts on the triode/UL switches. Silver bearing solder is used throughout.
All resistors are audio grade from PRP, TKD, and Mills. Caps are Clarity Caps. The volume control is Alps.
wiring is all point to point using an IAG terminal board i retrofitted with 8 pin sockets for the output tubes.
Rectification is FWBs using IXYS FRED diodes. Each channel has its own bridge and PS caps which are all poly film caps.
within reason everything is overbuilt to last.
Did I mention it sounds great too? Lol
Very few of us are able to hear that frequency span. As do only a few loudspeaker systems & listening spaces where we live able to reproduce them.
What other qualities fill in the differences? How do we separate the sound of the OPTs from that of the KT150s?.
And the selection of the PS used? And many other variables? As always, just curious.😀
My oscilloscope hears well past 20khz! I’m only good for about 16khz or so. My speakers are good to 22khz according to several reviews and my dog agrees. As far as tube vs opt, I originally prototyped with KT120s and some Transcendar opts I have. It sounded very very good. Since the Transcendars were needed back in the amp I hijacked them from, I did a little looking around and found these big units from HifiEquuis and took a chance. In place of the Transcendars they have more power in the very low end and more clarity in the mids and highs. I then thought I’d take advantage of the heavier opt and buy some KT150s. I’m glad I did as there is more of everything except noise and distortion. Friends that heard the amp with the 120 and thought it was amazing were astounded by the sound of the 150s. The comments were all very positive. As far as the ps caps go, I’m running over 500v B+ so it’s easier, longer lasting, and quieter with the film caps. All in all it’s a really good sounding amp that makes me happy, what more do I need than to be happy?
The primary of the opt is 3.5k with a UL tap and both 4 and 8 ohm outs.
The schematic is a slightly modified Alex G. design with two red LEDs and a 100 ohm resistor on the input tube instead of the 1k resistor in the original. The Ra can be from 470 to 510 depending on B+. I’m running mine at about 510v. The KT150 is biased at about 105ma. It’s best to keep it simple.
The schematic is a slightly modified Alex G. design with two red LEDs and a 100 ohm resistor on the input tube instead of the 1k resistor in the original. The Ra can be from 470 to 510 depending on B+. I’m running mine at about 510v. The KT150 is biased at about 105ma. It’s best to keep it simple.
Did build a SE KT150 years ago as well, but changed to KT120...see below...
https://www.diyaudio.com/community/threads/anyone-out-there-with-a-kt150.303273/
This amp is still one of my favorites. AS fas as sound is concerned, I do not remember much of a difference between KT150 and KT120.
Have the 150's still sleeping somewhere in the basement...
Marcus
https://www.diyaudio.com/community/threads/anyone-out-there-with-a-kt150.303273/
This amp is still one of my favorites. AS fas as sound is concerned, I do not remember much of a difference between KT150 and KT120.
Have the 150's still sleeping somewhere in the basement...
Marcus
Not the Raphellites, they were to expensive to take a random chance on. They get decent reviews but the ones I got were like $80 each plus big shipping. They are HifiEquis house branded 30w SE output transformers. I got 3.5k primaries but they have choices. They are unbeatable for the money and very good regardless of money.
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Those are reasonably priced- much different...
I've had good luck with HifiEquis on a custom PT order, then browsed their OT selection for possibility with current PP quad project...
Noticed sharp $ increase for Raphelites. Seems their makers are touting 'fully coupled windings' as holy grail- but I haven't found technical litmus test or much outside user feedback advantage of said design
Per my understanding of OT manufacture- isn't interleaving of Pri and Sec windings standard procedure?
If so, then what do these 'Raphelites' offer?
Perhaps winding resolution is greater? Instead of interleaving 5 or 10 windings, which is cheaper to produce...maybe 2 or 3 into smaller groups compounded into the windings ratio?
Don't mean to hi-jack your thread- but this is serious Q which pertains here- IMO
Jim
I've had good luck with HifiEquis on a custom PT order, then browsed their OT selection for possibility with current PP quad project...
Noticed sharp $ increase for Raphelites. Seems their makers are touting 'fully coupled windings' as holy grail- but I haven't found technical litmus test or much outside user feedback advantage of said design
Per my understanding of OT manufacture- isn't interleaving of Pri and Sec windings standard procedure?
If so, then what do these 'Raphelites' offer?
Perhaps winding resolution is greater? Instead of interleaving 5 or 10 windings, which is cheaper to produce...maybe 2 or 3 into smaller groups compounded into the windings ratio?
Don't mean to hi-jack your thread- but this is serious Q which pertains here- IMO
Jim
Most of the reasonably priced transformers are 3:2 interleaved from what I’ve seen. These are done that way and sound really great, especially for the money. I’ve got a pair of their 22 watt units that are of the same quality. As an added bonus they’re not gentian blue! No repainting is needed! Mine still smelled of fresh paint when they arrived!
I've seen that 3:2 reference- maybe that means 1/3, 1/2, 1/3, 1/2, 1/3 alternating pri/sec winding sequence on bobbin.
The raphelites show 5 primary windings & 8 secondary. Perhaps alternating all 13. Says 10hz-45khz within 1db. If I were to pay that much I'd want an explanation as to how they're made- but wouldn't hold my breath 🤔
https://www.aliexpress.us/item/3256802940044574.html?
Those Raphelites look physically exactly like the HifiEquis ones I have. I don’t know what justifies double the price even if there are more interleaves. Try the cheaper ones, I’m very happy with them.
I haven’t tried the KT170s and don’t think I will due to the price vs performance. You’d have to increase everything’s ratings and not het much more out if you are doing SE. PP would be monsterous, easily over 200 watts.
I haven’t tried the KT170s and don’t think I will due to the price vs performance. You’d have to increase everything’s ratings and not het much more out if you are doing SE. PP would be monsterous, easily over 200 watts.