ok thanks
the last thing i wish to do is hurt anything
here in canada we have plitron makers of really good toroids
i looked at there site tonight and 1 the same value is $116 canadian.
but i checked for a toroidish opt and they only make higher impedance.
can i get maybe a 500va rated with the same rails . any advantage in bigger transformer as in solid state?
so this will power the circuit and the tubes right?
so still will need something to do all the rest of power needs right?
the last thing i wish to do is hurt anything
here in canada we have plitron makers of really good toroids
i looked at there site tonight and 1 the same value is $116 canadian.
but i checked for a toroidish opt and they only make higher impedance.
can i get maybe a 500va rated with the same rails . any advantage in bigger transformer as in solid state?
so this will power the circuit and the tubes right?
so still will need something to do all the rest of power needs right?
The AnTek AS-2T350 toroidal power trafo will provide plenty of B+ current. Over 100 mA. are in reserve.
More than enough 6.3 VAC heater current is available too.All that remains is the O/P tube bias (C-) and, possibly, a low voltage negative rail for a LTP tail constant current sink (CCS) load. Let's postpone that stuff, for a while. If only an O/P tube bias rail is needed, we can go to Jim McShane for a pair of the parts kits he offers for the Harman/Kardon Citation II. The H/K Cit. 2 is 1 of the very best PP KT88 amps, ever. Unfortunately, we can't try replicating it, as the "super/duper" O/P trafos needed are unavailable. BTW, the H/K Cit. 2 is a 32 Kg. stereoblock.
If the bias supply is "instant" on, even a tiny delay in B+ rise, which can be achieved with an inrush current limiting thermistor, is sufficient.
Don't buy those Plitron toroids, until I have carefully examined their specifications, for adequacy. Just provide a link to the product description.
BTW, there is a "better" way to stage the energizing of trafo primaries than multiple switches thrown by the user. I am going to use the method (a combination of an Amperite thermionic delay relay and a conventional electromagnetic DPDT relay) in a PP Type 46 amp I'm slowly gathering steam on.
Don't buy those Plitron toroids, until I have carefully examined their specifications, for adequacy. Just provide a link to the product description.
BTW, there is a "better" way to stage the energizing of trafo primaries than multiple switches thrown by the user. I am going to use the method (a combination of an Amperite thermionic delay relay and a conventional electromagnetic DPDT relay) in a PP Type 46 amp I'm slowly gathering steam on.
the plitron toroids
https://shop.plitron.com/shopexd.asp?id=160
also eli these are 1 week to get shipped and i really need the related parts to get the right scale for the chassis height
the only reason i thought the warm up feature was good is the st70 i had would make a clunk sound when turn on from instant shocking cold parts
i do not want to hurt any parts so all ears
thanks so much
gordie
https://shop.plitron.com/shopexd.asp?id=160
also eli these are 1 week to get shipped and i really need the related parts to get the right scale for the chassis height
the only reason i thought the warm up feature was good is the st70 i had would make a clunk sound when turn on from instant shocking cold parts
i do not want to hurt any parts so all ears
thanks so much
gordie
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that is perfect clear news eli thank you
the antek has the 6.3v tap and i only thought the plitron when i was going after the warm up phase that now is gone .
so antek are already purchased $214 cdn for the 2 after shipping duty and money exchange.
i can't wait to get going on this
very excited
the antek has the 6.3v tap and i only thought the plitron when i was going after the warm up phase that now is gone .
so antek are already purchased $214 cdn for the 2 after shipping duty and money exchange.
i can't wait to get going on this
very excited
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![URL]](/community/proxy.php?image=http%3A%2F%2F%5BURL%3Dhttp%3A%2F%2Fs400.photobucket.com%2Fuser%2F91owner%2Fmedia%2FKT88%2520push%2520pull%2520monoblock%2520tube%2520amps%2Ftube%2520monoblock%2520build%25201.jpg.html%5D%5BIMGDEAD%5Dhttps%3A%2F%2Fi400.photobucket.com%2Falbums%2Fpp87%2F91owner%2FKT88%2520push%2520pull%2520monoblock%2520tube%2520amps%2Ftube%2520monoblock%2520build%25201.jpg%5B%2FIMGDEAD%5D%5B%2FURL%5D&hash=2f467cd1784c60a01e047cefd666766a)
today i received the 2 antek as-3t325 toroids and these are fantastic big heavy manly works of art, i mean my jaw dropped upon opening the shipping box. i was expecting 300va to be way smaller but this first look totally changes my ideas and chassis scale.
no way in hell i can mount these bad boys under the chassis out of sight .
eli thank you thank you thank you for turning me around to antek.
so impressed with the quality and price as well as ease to order that i have ordered 2 more toroids for another ss project.
i see that antek offer round cans to cover and this will be mounted on top now
no way in hell i can mount these bad boys under the chassis out of sight .
eli thank you thank you thank you for turning me around to antek.
so impressed with the quality and price as well as ease to order that i have ordered 2 more toroids for another ss project.
i see that antek offer round cans to cover and this will be mounted on top now
An externally hosted image should be here but it was not working when we last tested it.
A nice thing about toroids is their small stray magnetic field. You worry about keeping your EI magnetics' cores orthogonal and "ignore" the toroids.
Toroids exhibit wide bandwidth and that can lead to noise riding on the AC mains creeping into the amp. You deal with that by mounting ferrite beads on primary wires.
Toroids exhibit wide bandwidth and that can lead to noise riding on the AC mains creeping into the amp. You deal with that by mounting ferrite beads on primary wires.
thanks eli
what ever it takes as these toroids has a sense of finished size and these are going for a manly mono block .
thank you kward
circuit i'm planning is the opus 5.0 but with 4 kt88 each if i can pull it off.
as far as the opt goes eli instructed the use of a edcor 3.3k 100 watt and these are ordered.
i am just starting to fill the list of components . all tubes are expected in the next few days .
i was all set on chassis size and going to assemble this weekend but these transformers have changed that.
i really want to have all power supply finished and tubes wired to at least see them glow and check voltages.
Everything I've said is for a PP pair of KT88s. I was wondering about the cardboard templates. 
The Edcor O/P "iron" has a correct primary impedance for a KT88 PP pair. A quartet of "finals" would use approx. 1.6 Kohm primary O/P "iron". Remember, P = V2/R. The voltage swing of a pair or a quartet, with the same operating conditions, is the same. To double the power, halve the impedance.
The 100 W. rating is "right" for a PP pair, as magnetic headroom is NECESSARY to deal with the deep bass error correction associated with the GNFB loop.
The Edcor O/P "iron" has a correct primary impedance for a KT88 PP pair. A quartet of "finals" would use approx. 1.6 Kohm primary O/P "iron". Remember, P = V2/R. The voltage swing of a pair or a quartet, with the same operating conditions, is the same. To double the power, halve the impedance.
The 100 W. rating is "right" for a PP pair, as magnetic headroom is NECESSARY to deal with the deep bass error correction associated with the GNFB loop.
Not quite point to point...there is a PCB in there under all the light bulbs.
But...the VTA ST-120 amp is a nice amp for a newbie. Comes as a complete kit with detailed easy to follow instructions. If you want more power there are the M-125 monoblocks like in the photo.
Tubes4hifi has nice amps. Personally I'd stay away from the preamps though.
But...the VTA ST-120 amp is a nice amp for a newbie. Comes as a complete kit with detailed easy to follow instructions. If you want more power there are the M-125 monoblocks like in the photo.
Tubes4hifi has nice amps. Personally I'd stay away from the preamps though.
thanks for your thoughts
but not a fan of chrome or square chassis or even the packed look but the power rating is attracting.
kt88 quad and 12at7 tubes came today so just the opt and wiring can begin.
please correct me but looking at kt88 pinout on the web ans is it the heater on pin 2 and 7?
[image removed]
but not a fan of chrome or square chassis or even the packed look but the power rating is attracting.
kt88 quad and 12at7 tubes came today so just the opt and wiring can begin.
please correct me but looking at kt88 pinout on the web ans is it the heater on pin 2 and 7?
[image removed]
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According to your image.
Pins 2 & 7 are heater
Pin 1 is shield or No Connection (depends on tube manufacturer).
Pin 3 is Plate / Anode
Pin 4 is G2 or Grid #2. UL connection if using UL mode.
Pin 5 is G1 or Grid #1. Coupling capacitor (signal) from previous stage.
Pin 8 is cathode. (internally connected to G3)
Pins 2 & 7 are heater
Pin 1 is shield or No Connection (depends on tube manufacturer).
Pin 3 is Plate / Anode
Pin 4 is G2 or Grid #2. UL connection if using UL mode.
Pin 5 is G1 or Grid #1. Coupling capacitor (signal) from previous stage.
Pin 8 is cathode. (internally connected to G3)
thank you for your help. i apologize to you all for what you must think are newbe green questions.
basic understanding was not in my brain at the start. i'm 54 so not new only to tubes.
does ul mode mean ultra linear?
and if so does ultra linear mean the most wattage out?
but all of your help has taught me some milestones in the building of my first tube builds from scratch.
today i got 4 rolls of 600v rated 16 ga wire red, black, white and yellow and the ceramic 9 pin sockets .
basic understanding was not in my brain at the start. i'm 54 so not new only to tubes.
does ul mode mean ultra linear?
and if so does ultra linear mean the most wattage out?
but all of your help has taught me some milestones in the building of my first tube builds from scratch.
today i got 4 rolls of 600v rated 16 ga wire red, black, white and yellow and the ceramic 9 pin sockets .
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No need to apologize, we all had to learn and I still am (I'm 54 as well).
Correct, UL is an abbreviation for Ultra Linear or in the U.K. its called "distributed loading".
It is not about most power out, Tetrode mode in the case of the KT88 or Pentode mode with a pentode e.g. 6BQ5 gives the most power. Bear in mind it takes twice a given amount of power to make a 3dB increase in sound, 3dB being the minimum difference we can hear.
Ultra Linear is more about a mode of operation that is between Triode mode and Tetrode / Pentode mode. You supposedly get a smoother sound than the Pentode mode but with a little less power, another trade off or compromise.
Correct, UL is an abbreviation for Ultra Linear or in the U.K. its called "distributed loading".
It is not about most power out, Tetrode mode in the case of the KT88 or Pentode mode with a pentode e.g. 6BQ5 gives the most power. Bear in mind it takes twice a given amount of power to make a 3dB increase in sound, 3dB being the minimum difference we can hear.
Ultra Linear is more about a mode of operation that is between Triode mode and Tetrode / Pentode mode. You supposedly get a smoother sound than the Pentode mode but with a little less power, another trade off or compromise.
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