Yeah, I want to hear about the rest of Johan's test results before proceding. He still has part 2 to do on feedback, and final values, and I think he's currently researching a possible driver change? A final OK from SY and Eli would be reassuring too. At that point, I would like to hear what the other builders have in mind for those OT's. I'm stuck on about 3 or 4 different choices currently. You builders start thinking about that.
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I agree, my comments were a little gung ho. I was a little confused after reading all the pages in a day what the current schema was. Thanks for posting it Taj. My table is clear however from my other projects so I will pull the trigger when it is ready.
I don't have any experience with PP OPT's. But for SE, Electra-print and Edcor have been excellent performers. IMO, the Electraprint are better sounding, however, the Edcor's really suprised me in sound quality. The Hammond was recomended earlier as a possibility but I don't think I will go that route. Of course there is good iron from across either pond.
I don't have any experience with PP OPT's. But for SE, Electra-print and Edcor have been excellent performers. IMO, the Electraprint are better sounding, however, the Edcor's really suprised me in sound quality. The Hammond was recomended earlier as a possibility but I don't think I will go that route. Of course there is good iron from across either pond.
Yes, SS rectification. Don't know the resistance, have not received the transformers yet. They should be here next week.
It's time to begin shopping for good KT88's. This web page is truly fascinating:
KT88 and 6550 Tube Directory
..Todd
KT88 and 6550 Tube Directory
..Todd
If you have the cash, buy "reissue" Gold Lion KT88s. Otherwise, buy EH KT88s. The only other serious contender is the SED (=C=) 6550C. Sadly, Chinese KT88s' quality has declined badly. 😡
Regardless of the variant you chose, Jim McShane is your source. Jim takes the time and trouble to properly cull and match specimens. No pig in a poke here. 🙂
The reissue brands are my first choice as well, would not like to rely on expensive NOS that becomes just more expensive for every day and sooner or later extinct.
Seems like JJ is my only choice to try out the ECC99, the good thing is it's pin compatible with 12AT7 though I would like to bias ECC99 much harder than 12AT7, maybe around 10-15 mA so would have to add 2 new resistors to each plate pin. 🙂
How about our input tube, have settled for EF86?
Todd I'm happy for you guys in Canada, Vancouver is a wonderful city with or without the Olympics, just read yesterday Vancouver was voted the best city in the world to live in.
Cheers Michael
Seems like JJ is my only choice to try out the ECC99, the good thing is it's pin compatible with 12AT7 though I would like to bias ECC99 much harder than 12AT7, maybe around 10-15 mA so would have to add 2 new resistors to each plate pin. 🙂
How about our input tube, have settled for EF86?
Todd I'm happy for you guys in Canada, Vancouver is a wonderful city with or without the Olympics, just read yesterday Vancouver was voted the best city in the world to live in.
Cheers Michael
I sent an email to Jim. Will probably go with the Gold Lion From Him.
I will say from the link above, I am interested in the GU50. It looks cool.
Anybody bought iron yet, I am leaning toward a lower source impedance based on my SET experience, but not sure what is correct for PP.
I will say from the link above, I am interested in the GU50. It looks cool.
Anybody bought iron yet, I am leaning toward a lower source impedance based on my SET experience, but not sure what is correct for PP.
Someone earlir mentioned the Hammond 1650R, it's on sale right now at Angela Instruments for $90ea. I bought a pair this morning.
I believe we will end up with at least 2 versions. The 6GK5 version seems to be progressing, albeit as slowly as genetic evolution.
Hmm... Best city to live in as determined by statisticians from another country no doubt. I have no complaints other than the gray skies and rain (think Seattle). Give me any city in Northern California instead, if just to get some damn sunshine. But then, I probably wouldn't find a hockey team to join there. 🙄
..Todd
I think that I will go for the EDCOR CXPP100-MS-4.2K. 100W 4.2K primary. $92.87.
I want a little more power. They make a 5k version as well if that is a problem.
My concern with the 4.2k selection is that it will lead to higher 3rd order harmonics in PP. Can somebody help with my thoughts on this as I am only able the hypotesize my reasoning.
I want a little more power. They make a 5k version as well if that is a problem.
My concern with the 4.2k selection is that it will lead to higher 3rd order harmonics in PP. Can somebody help with my thoughts on this as I am only able the hypotesize my reasoning.
Tubes aren't my area of expertise but they are similar to any other gain device (transistors and FETs with which I am more familiar with) so the little I can read out from tube data sheets are that they become within some limits of range more linear for higher currents, and lower input impedance needs higher currents to maintain the same output power, just my 2c of guess.
Cheers Michael
Cheers Michael
Go back and read the thread from the beginning. We discussed this subject pretty early on. I did an analysis from a voltage swing perspective and that clearly showed the "correct" O/P trafo to be Edcor's 3.3 kOhm primary model CXPP100-MS-3.3K. FWIW, there's more than 1 method for approaching the primary impedance issue. I find voltage swing analysis to be quite convincing.
Ok Here is my list of Iron unless somebody points to a flaw in reasoning.
EDCOR
XPWR002 720VCT 220mA w 60Vbias and misc.
PWRC6.3V3A-1 Filament power 6.3VCT 3A I want to warm up filaments seperate.
CXPP100-MS-3.3k 100W Could go up on primary impedance with a nudge. I saw several different values prior in the thread
Electraprint
Choke (Good price and solid and I mean solid performers) I need to talk to Jack to see if he can get a higher H with similar or lower DCR. 300mA
What would be a good source for the 1.5mH hash choke?
I know this isn't the time to be stupid, but I have (4) 3500uF 450VDC caps on my shelf. Since this is a SS rectifier with thermistor application, I will be pulling out PSUDII to see if I can get them charged. Otherwise I will stick to the 330uF.
(These things are driving me crazy as I would love to find a home for them without an industrial transformer.)
EDCOR
XPWR002 720VCT 220mA w 60Vbias and misc.
PWRC6.3V3A-1 Filament power 6.3VCT 3A I want to warm up filaments seperate.
CXPP100-MS-3.3k 100W Could go up on primary impedance with a nudge. I saw several different values prior in the thread
Electraprint
Choke (Good price and solid and I mean solid performers) I need to talk to Jack to see if he can get a higher H with similar or lower DCR. 300mA
What would be a good source for the 1.5mH hash choke?
I know this isn't the time to be stupid, but I have (4) 3500uF 450VDC caps on my shelf. Since this is a SS rectifier with thermistor application, I will be pulling out PSUDII to see if I can get them charged. Otherwise I will stick to the 330uF.
(These things are driving me crazy as I would love to find a home for them without an industrial transformer.)
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OK, since we're now discussing OT's........
Being on this side of the pond, my considerations are currently:
Hammond 1650R
Edcor 100W
Electra Print 100W
O'netics (From Bud here on the forum) 100W
Is there a clear winner cost being ignored? I'm looking for a "step up" in SQ from my trannies in the ST-70.
Bandersnatch Loves the Hammond1650R, and I listen when he speaks. That said Hammonds in general seem to fail in head to head comparisons with the others. I've searched everyway possible, but can not find any other agreement with that pick. Has anyone else heard that Tranny compared to anything else?
Being on this side of the pond, my considerations are currently:
Hammond 1650R
Edcor 100W
Electra Print 100W
O'netics (From Bud here on the forum) 100W
Is there a clear winner cost being ignored? I'm looking for a "step up" in SQ from my trannies in the ST-70.
Bandersnatch Loves the Hammond1650R, and I listen when he speaks. That said Hammonds in general seem to fail in head to head comparisons with the others. I've searched everyway possible, but can not find any other agreement with that pick. Has anyone else heard that Tranny compared to anything else?
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You won't go wrong with Electraprint. If you reallly want to go Audiophile he also has the PSS secondary. The Hammond 1650R lists as a 5k primary, however never heard it. I do trust ELI's comments about primary impedance, and I also prefer my SET's with a lower impedance.
I don't know anything about Bud's xfmrs other than what I have read. People do seem to like them.
Both Bud and Jack would probably give insight to what would be the best OPT based on their experience and winding tricks.
FYI scratching the idea of the big caps. Would let out the magic smoke in a "normal" PT. Nice ripple though 0.92mV..
I don't know anything about Bud's xfmrs other than what I have read. People do seem to like them.
Both Bud and Jack would probably give insight to what would be the best OPT based on their experience and winding tricks.
FYI scratching the idea of the big caps. Would let out the magic smoke in a "normal" PT. Nice ripple though 0.92mV..
Put a series wired pair,with voltage equalizing resistors, after a 10 H. choke, in the reservoir position. The choke will shield the rectifiers and power trafo from the HUGE capacitance. The rail will rise slowly, as the DCR of the choke combines with the caps. to form a time constant. The voltage equalizers will do double duty as the essential bleeders.
Mouser, look here.
If you are going to use a separate filament trafo, the AnTek model AN-2T350 is nearly ideal. Parallel the 350 V. windings, wire 1 of the 6.3 V. windings in series with the 350 V windings, using the boost configuration, and bridge rectify the composite. Voltage multiply the 2nd 6.3 V. winding to derive any and all negative rails necessary. Snubbed UF5408s on the ground side of the HT bridge and 3 A./600 PIV Schottkys on the "hot" side will kick butt.
I sent an email to BudP asking for a price on some O'Netics OPT. I'll let you know what the response is.
I like this option if he accepts local pick-up since he's a Sunday drive down the street in Seattle. That lack of shipping/importing cost may buy me a lot of extra iron quality.
..Todd
I like this option if he accepts local pick-up since he's a Sunday drive down the street in Seattle. That lack of shipping/importing cost may buy me a lot of extra iron quality.
..Todd
Bud's response:
OPT's from O-Netics
Hi Todd,
For a set of M6 core, level one devices we would charge $140 each, for a pair. Were there to be a group buy that price could get quite a bit closer to Edcores $93 each. Edcore makes a fine product, but it is not aimed at maximum information retention and our OPT's will provide 3 to 4 times the amount of internal gradient information for notes and transients. Our distortion should be under 0.01% from 250 Hz to 35 kHz and our frequency response will be flat to 40 kHz and ourt phase will be flat to 35 kHz, regardless of power level. We do make a level two and level three. Level two uses M3 core and typically costs $280 each in pairs. Larger group buys will bring that price down also. I even have a fair stock of the appropriately sized M3 core on hand.
We can provide any sort of load line that is needed and could even split a group buy up into various reflected impedance to suit various individuals needs. Thie is just an adjustment to secondary turns count, since we want the primary to maintain the required inductance and a change from 3.3 to 5 kZ ohms will not make a dent in that requirement.
We are a custom house, we build to CE 6500 specs only and it would take us 8 weeks to provide the units. We do ask for full payment for the transformers up front and will be happy to charge the exact freight to each purchaser, anywhere in the world. Payment can be either Pay Pal with a 4% add on to cover their charges or by personal or business check drawn on a US bank. I do quite a brisk business world wide in both Audio reproduction powers and OPT's and the same in Guitar iron.
I would be happy to work with your group in any way I can help. You might have everyone read this thread that I have been participating in, on, of all things, output transformer design and choice.
http://www.diyaudio.com/forums/tubes-valves/157920-choosing-output-transformer.html
Do please provide me with a link to your thread and I can comment there if needed. [Todd's note: Done]
Bud
OPT's from O-Netics
Hi Todd,
For a set of M6 core, level one devices we would charge $140 each, for a pair. Were there to be a group buy that price could get quite a bit closer to Edcores $93 each. Edcore makes a fine product, but it is not aimed at maximum information retention and our OPT's will provide 3 to 4 times the amount of internal gradient information for notes and transients. Our distortion should be under 0.01% from 250 Hz to 35 kHz and our frequency response will be flat to 40 kHz and ourt phase will be flat to 35 kHz, regardless of power level. We do make a level two and level three. Level two uses M3 core and typically costs $280 each in pairs. Larger group buys will bring that price down also. I even have a fair stock of the appropriately sized M3 core on hand.
We can provide any sort of load line that is needed and could even split a group buy up into various reflected impedance to suit various individuals needs. Thie is just an adjustment to secondary turns count, since we want the primary to maintain the required inductance and a change from 3.3 to 5 kZ ohms will not make a dent in that requirement.
We are a custom house, we build to CE 6500 specs only and it would take us 8 weeks to provide the units. We do ask for full payment for the transformers up front and will be happy to charge the exact freight to each purchaser, anywhere in the world. Payment can be either Pay Pal with a 4% add on to cover their charges or by personal or business check drawn on a US bank. I do quite a brisk business world wide in both Audio reproduction powers and OPT's and the same in Guitar iron.
I would be happy to work with your group in any way I can help. You might have everyone read this thread that I have been participating in, on, of all things, output transformer design and choice.
http://www.diyaudio.com/forums/tubes-valves/157920-choosing-output-transformer.html
Do please provide me with a link to your thread and I can comment there if needed. [Todd's note: Done]
Bud
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