hey-Hey!!!,
the three 'main' windings are all 8:1 re. the 8 ohm tap. 12 Ohms CT to end, as quoted in the manual. All the same DCR. I can take AC to it again, and get the feedback winding ratio, but not for a few days...
regards,
Douglas
the three 'main' windings are all 8:1 re. the 8 ohm tap. 12 Ohms CT to end, as quoted in the manual. All the same DCR. I can take AC to it again, and get the feedback winding ratio, but not for a few days...
regards,
Douglas
Where have you gotten this 1k idea from?
regards,
Douglas
BTW, I might pul the hood off of it tonite, not before.
regards,
Douglas
BTW, I might pul the hood off of it tonite, not before.
please take another look at post#15:
i'd like to get the facts straightened out, then i will come out with a design...
regards,
tony
i'd like to get the facts straightened out, then i will come out with a design...
regards,
tony
mc275
iron core is grain oriented steel...Turns ratio and impedance is mentioned on "History of McIntosh Laboratory Part 1 by Roger Russel" I only have a hard copy and all other specs such as dc resistance is written on service manual I've got. I doubt all CT windings are same because cathode winding has only 600 Ohms (230v) and I believe it has different current while reflected voltage on 1k primary I assume is 274 volts. If Douglas has the stuff, I'll be thankfull and appreciate if you can peep through inside and get the wire size.
iron core is grain oriented steel...Turns ratio and impedance is mentioned on "History of McIntosh Laboratory Part 1 by Roger Russel" I only have a hard copy and all other specs such as dc resistance is written on service manual I've got. I doubt all CT windings are same because cathode winding has only 600 Ohms (230v) and I believe it has different current while reflected voltage on 1k primary I assume is 274 volts. If Douglas has the stuff, I'll be thankfull and appreciate if you can peep through inside and get the wire size.
mc275
I'm thinking that Douglas is right for turns ratio. As I have searched, cathode winding is 8:1 (cathode to cathode), however, as for the primary winding, he measured maybe one half of the windings because the tranformer is wound in 2 separate sections or wound side by side in split bobbin.
I'm thinking that Douglas is right for turns ratio. As I have searched, cathode winding is 8:1 (cathode to cathode), however, as for the primary winding, he measured maybe one half of the windings because the tranformer is wound in 2 separate sections or wound side by side in split bobbin.
hi,
i think so too, i am looking for my copy of audio magazine wherein they reviewed a luxman tube power amp that has a strikingly similar design as that of the macs...as far as the output is concerned....
can you post the links to: "History of McIntosh Laboratory Part 1 by Roger Russel" or can you scan and email me?
wire size is no problem for me it can easily be ascertained given the plate currents and output power....i just need to get the impedeance relationships between windings right and all else follows...
tony
i think so too, i am looking for my copy of audio magazine wherein they reviewed a luxman tube power amp that has a strikingly similar design as that of the macs...as far as the output is concerned....
can you post the links to: "History of McIntosh Laboratory Part 1 by Roger Russel" or can you scan and email me?
wire size is no problem for me it can easily be ascertained given the plate currents and output power....i just need to get the impedeance relationships between windings right and all else follows...
tony
Mc275
Dear Joan2,
I can't make link, but
some informations I have are from :
http://www.Roger-russel.com/mcintosh1.htm
There are two part history, and 1k impedance is mentioned in page 2.
http://www.berners.ch/McIntosh/Downloads/MC275_own.pdf
Instruction manual of the original Mc275.
They made a replica of their commemorative model which they produce last 1995(I think) for $15,000.00. They call it "re-issue"
and produce about 500 units and it's a hot cake.
http://www.audiophool.cjb.net/misc/mac1949.pdf
A description of unity coupled transformer winding.
http://www.mc275.com
Some specifications mentioning the trifilar.
http://kssons.com
Golden specifications
http://perso.wanado.fr/michel.terrier/radiocol/detailmcintoshmc275.htm
RARE & Legendary
here is a site which I'm not sure off will open :
Review Asylum\Dossier technique-technical file.htm
You can surf any of the following i did'nt get the address but I have all the hard copy i can send out to you.
SAM TELLIG Listen to Tube
McIntosh Unity coupled circuit
PATENT of the unity coupled transformer invented by Frank Mc before the Ultralinear invented by David Hafler & Herbert Keroes
Mc275 re-issue
Dear Joan2,
I can't make link, but
some informations I have are from :
http://www.Roger-russel.com/mcintosh1.htm
There are two part history, and 1k impedance is mentioned in page 2.
http://www.berners.ch/McIntosh/Downloads/MC275_own.pdf
Instruction manual of the original Mc275.
They made a replica of their commemorative model which they produce last 1995(I think) for $15,000.00. They call it "re-issue"
and produce about 500 units and it's a hot cake.
http://www.audiophool.cjb.net/misc/mac1949.pdf
A description of unity coupled transformer winding.
http://www.mc275.com
Some specifications mentioning the trifilar.
http://kssons.com
Golden specifications
http://perso.wanado.fr/michel.terrier/radiocol/detailmcintoshmc275.htm
RARE & Legendary
here is a site which I'm not sure off will open :
Review Asylum\Dossier technique-technical file.htm
You can surf any of the following i did'nt get the address but I have all the hard copy i can send out to you.
SAM TELLIG Listen to Tube
McIntosh Unity coupled circuit
PATENT of the unity coupled transformer invented by Frank Mc before the Ultralinear invented by David Hafler & Herbert Keroes
Mc275 re-issue
Mc275
Dear Joan2,
Link correction :
http://www.roger-russell.com/mcintosh1.htm
http://perso.wanadoo.fr/michel.terrier/radiocol/detail/mcintoshmc275.htm
Dear Joan2,
Link correction :
http://www.roger-russell.com/mcintosh1.htm
http://perso.wanadoo.fr/michel.terrier/radiocol/detail/mcintoshmc275.htm
Mc275
Dear Joan2,
Link correction :
http://www.roger-russell.com/mcintosh1.htm
http://perso.wanadoo.fr/michel.terrier/radiocol/detail/mcintoshmc275.htm
If you want to see the schematic, try
http://drtube.com/audioamp.htm
Dear Joan2,
Link correction :
http://www.roger-russell.com/mcintosh1.htm
http://perso.wanadoo.fr/michel.terrier/radiocol/detail/mcintoshmc275.htm
If you want to see the schematic, try
http://drtube.com/audioamp.htm
mc275
Tony, If you want to analyse the DCR ,
see the attached pls.
Drive winding is connected to 12AZ7 pin # 1 & 6
Primary winding connected to kt88 Pin #3
cathode winding connected to kt88 Pin # 8
I'll send the schematic, pls wait
Tony, If you want to analyse the DCR ,
see the attached pls.
Drive winding is connected to 12AZ7 pin # 1 & 6
Primary winding connected to kt88 Pin #3
cathode winding connected to kt88 Pin # 8
I'll send the schematic, pls wait
looking at what the intentions of the designer were, i deduced the following:
1. separate feedback winding was used because the amp was intended to be paralleled for greater output of 150 watts mono, so if you do not intend to go this route, we can dispense with the separate windings for feedback and just ground the common terminal and take the feedback from the 16 ohm tap which is costumary...
2. likewise with the cathode feedback winding, if you do not need the line outs,(i doubt you will ever find use for this!) then the cathode feedback windings can de done sans the taps, to simplify winding the traffo.
with those out of the way, i believe hacking the traffo would be less complicated....
would appreciate inputs from tube gurus here!!!
tony
1. separate feedback winding was used because the amp was intended to be paralleled for greater output of 150 watts mono, so if you do not intend to go this route, we can dispense with the separate windings for feedback and just ground the common terminal and take the feedback from the 16 ohm tap which is costumary...
2. likewise with the cathode feedback winding, if you do not need the line outs,(i doubt you will ever find use for this!) then the cathode feedback windings can de done sans the taps, to simplify winding the traffo.
with those out of the way, i believe hacking the traffo would be less complicated....
would appreciate inputs from tube gurus here!!!
tony
mc275
Apppreciate your analysis ,but still the amplifier is an intriguing one as the unity coupled trafo effectively makes a very clean, cooler,etc. that surpassed the fidelity of todays amps. And why it requires a specially made output transformer, which limits its universality..
They reproduce again this same circuit in Mc2000 and 2102 with
a two entirely separated power amp & power supplies and
am assembling it based on their new electronically regulated power supplies.
This new model "line out" was removed already but still uses the
cathode winding , perhaps yes that there is an echo of "ciclotron"
theory about it that I can't explain.
I have to challenge myself that I can make it because I already
heard it in Malabon Amp. competition...I also usually see movie
in "Sky Theater" in Taytay, Rizal just to hear the sounds.
My friend has this 275 stuff but selling it for half million peso and
didn't allow me to mesh with transformer. Now that new model
cost 1 million, 'am still dreaming to have it.
Apppreciate your analysis ,but still the amplifier is an intriguing one as the unity coupled trafo effectively makes a very clean, cooler,etc. that surpassed the fidelity of todays amps. And why it requires a specially made output transformer, which limits its universality..
They reproduce again this same circuit in Mc2000 and 2102 with
a two entirely separated power amp & power supplies and
am assembling it based on their new electronically regulated power supplies.
This new model "line out" was removed already but still uses the
cathode winding , perhaps yes that there is an echo of "ciclotron"
theory about it that I can't explain.
I have to challenge myself that I can make it because I already
heard it in Malabon Amp. competition...I also usually see movie
in "Sky Theater" in Taytay, Rizal just to hear the sounds.
My friend has this 275 stuff but selling it for half million peso and
didn't allow me to mesh with transformer. Now that new model
cost 1 million, 'am still dreaming to have it.
"I have to challenge myself that I can make it because I already
heard it in Malabon Amp. competition...I also usually see movie
in "Sky Theater" in Taytay, Rizal just to hear the sounds."
humm...i used to bring my girlfriend to watch movies at the "Sky Theater", i live in Pasig City, are you from Taytay? we are neighbors then....i did not occur to me that they were using those kind of amps in that theater....
there was a competetion in malabon just this march, i believe in Dampalit....but i missed that one....
tube watt somehow does not give the same impression as ss watts, i remember during our high school days at the Rizal HIgh School, we used this 6l6 power amps rated at 35 watts yet seem to fill the track oval with sounds using two sets of horns....those were the days!!!
your mc275 quest, is not an unreachable goal, i will help you get your output traffo, after i have gotten all the facts....
heard it in Malabon Amp. competition...I also usually see movie
in "Sky Theater" in Taytay, Rizal just to hear the sounds."
humm...i used to bring my girlfriend to watch movies at the "Sky Theater", i live in Pasig City, are you from Taytay? we are neighbors then....i did not occur to me that they were using those kind of amps in that theater....
there was a competetion in malabon just this march, i believe in Dampalit....but i missed that one....
tube watt somehow does not give the same impression as ss watts, i remember during our high school days at the Rizal HIgh School, we used this 6l6 power amps rated at 35 watts yet seem to fill the track oval with sounds using two sets of horns....those were the days!!!
your mc275 quest, is not an unreachable goal, i will help you get your output traffo, after i have gotten all the facts....
Mc275
I am Ricardo del Rosario, I was born in Taytay , a graduate of Saint Catherines Academy (batch 1974) Employed with Panasonic Taytay since 1976.
I used to be a repairman of sky theater amp in high school days.
Married in Taytay and now lived in Antipolo. My two daughters are in Panasonic Laguna.
Still crazy about audio because i meshed with circuit since 16 years old and studied electronics NTS California corresponce.
I am Ricardo del Rosario, I was born in Taytay , a graduate of Saint Catherines Academy (batch 1974) Employed with Panasonic Taytay since 1976.
I used to be a repairman of sky theater amp in high school days.
Married in Taytay and now lived in Antipolo. My two daughters are in Panasonic Laguna.
Still crazy about audio because i meshed with circuit since 16 years old and studied electronics NTS California corresponce.
I am still thinking of what Douglas has measured. He was right but we have to confirm once more. (Turns ratio as mentioned in Mac history part 1 may only be a theory in general mac equipment.)
I am hoping that he would pull again the hood and give us the final result.
I am hoping that he would pull again the hood and give us the final result.
hi,
we can still determine the turns ratio, if you can borrow your friends' amp, what you can do is pull-out all the power tubes, in fact all tubes...
then on the 16ohm tap, inject an ac voltage of say 10volts....
with a 10volts on the 16ohm tap, you should have 5volts on the 4ohm tap, and 7volts on the 8ohm tap...
now you can measure the ac volts at the plates of the output tubes, list it down, it should be plate to plate...
next do the same for the cathodes of the output tubes, this sould be cathode to cathode...
next is the plate to plate of the driver tubes....
with these simple steps we can determine turns ratio...
interleaving mentioned in the manual says 5 sections, so i suspect 3 sections for primary and 2 sections for secondary...
trifilliar winding can be of two kinds...we can decide later when we get the data...
depending on the internal resistance of your voltage source, it may drop as you connect it to the 16ohm tap so check the voltage at the connections before proceeding with the other measurements....
we can still determine the turns ratio, if you can borrow your friends' amp, what you can do is pull-out all the power tubes, in fact all tubes...
then on the 16ohm tap, inject an ac voltage of say 10volts....
with a 10volts on the 16ohm tap, you should have 5volts on the 4ohm tap, and 7volts on the 8ohm tap...
now you can measure the ac volts at the plates of the output tubes, list it down, it should be plate to plate...
next do the same for the cathodes of the output tubes, this sould be cathode to cathode...
next is the plate to plate of the driver tubes....
with these simple steps we can determine turns ratio...
interleaving mentioned in the manual says 5 sections, so i suspect 3 sections for primary and 2 sections for secondary...
trifilliar winding can be of two kinds...we can decide later when we get the data...
depending on the internal resistance of your voltage source, it may drop as you connect it to the 16ohm tap so check the voltage at the connections before proceeding with the other measurements....
Ten times I have requested my friend but hesitant to show me the internal unit. This is a collectors item, he know the controversy of unity coupled and about the secrecy. I tried to buy it for fifty Thousand when i have the money on hand but he insist on Two Hundred fifty bucks.
I have also requested the official rewinder of mac in U.S.A
begging to share the winding data (i have the E-mail)but said he cannot jeopardize good relationship with mac lab. He offer me $1700 for complete set.
I have also requested the official rewinder of mac in U.S.A
begging to share the winding data (i have the E-mail)but said he cannot jeopardize good relationship with mac lab. He offer me $1700 for complete set.
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