Is there anyone out there that has built 60 watt per channel KT88 amps using Hammond output transformers 1650n or 1650p. I am looking for proven circuitry and also need information on the line input transform in regaurds to voltage, do i use 400-0-400 and at what milliamp. If there is nothing existing available, is there any one who is willing to produce a design. I want to use hammond input and output with JJ kt88. I will be building 4 stereo units. I hope there is someone who can help. I sent here from the lansing forum, the moderator said this is the place where tubes experts reside. Don't make me go to china or japan
Hello
I are nearly finish building a Dynaco Mark III pp amplifier.
I an using a 1650N trafo as OPT.
My B+ is close to 500 Volts.
The schematic you can get at www.triodeel.com/schindex.htm
Regards
Benny
I are nearly finish building a Dynaco Mark III pp amplifier.
I an using a 1650N trafo as OPT.
My B+ is close to 500 Volts.
The schematic you can get at www.triodeel.com/schindex.htm
Regards
Benny
Well, I'll let the experts do the talking, but i have built a couple ultralinear KT88 amps with the 1650n... have on right in front of me actually. Somewhere around 450v on the plates idling around 55mA or so per tube I think puts out about 60 watts. Ned has some classic design posted over at triode electronics: http://www.triodeel.com/schindex.htm That might be a good place to start...depends on what you are driving with though.
The B+ required and the current required depend on the design. A Citation II runs an idle current of about 100mA per tube, other designs I've seen go as low as 60mA per tube.
Voltages on KT88 designs are often between 400 and 500.
A 350-0-350 power trafo should give a B+ of 400 to 450 volts with tube rectification, higher with solid state. I'm using 350VCT trafos with my SE KT88 amps with a 5U4G tube rectifier and have a B+ of about 425 volts.
Voltages on KT88 designs are often between 400 and 500.
A 350-0-350 power trafo should give a B+ of 400 to 450 volts with tube rectification, higher with solid state. I'm using 350VCT trafos with my SE KT88 amps with a 5U4G tube rectifier and have a B+ of about 425 volts.
Need lots more help in the Kt88 Hammond circuits
I have looked at the dynaco III amp circuits. I am trying to find a proven schematic with Hammond power tranformer complete with model number. I want to use the 1650p as the output. I look on hammond charts and see 350-0-350 or 400-0-400 volt transformers but i am not sure what amperages. What is the crossreference number for the dynaco III amp. I don't know enough to design engineer the circuits. Is there someone i can contact to have the circuits designed. I can't belive that there aren't circuits availble from hammond or someone who has built amps with these products. Where have all these transformer been used in the past?
I have looked at the dynaco III amp circuits. I am trying to find a proven schematic with Hammond power tranformer complete with model number. I want to use the 1650p as the output. I look on hammond charts and see 350-0-350 or 400-0-400 volt transformers but i am not sure what amperages. What is the crossreference number for the dynaco III amp. I don't know enough to design engineer the circuits. Is there someone i can contact to have the circuits designed. I can't belive that there aren't circuits availble from hammond or someone who has built amps with these products. Where have all these transformer been used in the past?
Re: Need lots more help in the Kt88 Hammond circuits
Check out Angela Instruments (www.angela.com). Go to the 'Transformers' page for the specs on the Hammond iron, including current capability.
Triode Electronics has some Dynaco replacment transformers that are drop-in replacments size wise.
jbldriven said:
Check out Angela Instruments (www.angela.com). Go to the 'Transformers' page for the specs on the Hammond iron, including current capability.
Triode Electronics has some Dynaco replacment transformers that are drop-in replacments size wise.
I have looked at the angle site and hammond. If the kt88 tube runs at 55 to 100 ma is the transform output based on 4 kt88 time the ma per tube eg 4 x 65ma=250 ma total. Therefore there is no 350-0-350 or 400-0-400 transform the will produce that current or is the ma 65 per push pull pair. Please be patient i have lot to learn.
Over the top
I've got a very nice prototype monoblock running using 4 off KT88 in Parallel Push Pull Ultralinear into Hammond 1650T trannies to give 135W.
Frequency response measured at 50W output was 65kHz at the high end and it was flat down to 22Hz at the low end but with some weird distortion setting in at around 18Hz due, I believe, to transformer core saturation. This would seem to stack up pretty well with hammonds claim of full power (120W) bandwidth of 30Hz to 30kHz
If interested then Go here:
http://www.evatco.com.au/project.htm
The 3rd project example down has a picture of the very agricultural prototype, the links for the schematic for the amplifier and the power supply and a link for the designers (me) comments. I did this amp around 2 years ago and rebuilding it to a decent chassis and doing the second channel is sort of gradually moving up the priority list. I also have PAT4006 Toroidal Output Trannies and tried them in place of the Hammond 1650Ts. The hughly higher primary inductance reduced lowe frequency 2nd harmonic distortion dramatically and the nominally 2100:5 impedance ratio compared to the Hammond 1900:4 required a bit more global feedback. Frankly I liked "Classic Tube Amp" sound that the Hammond imparted better than the pristine results from the Plitrons. My hip pocket liked the Hammonds a whole lot better too.
You will see that I used Cursio Audio Engineering (CAE) PCB1A boards for the front end. These boards were intended for upgrades of Dynaco MK3 Amps. The boards have a 6DJ8 (ECC88) cascode diffamp, with a current source tail and a high voltage regulator, These days you could also use 6N1P or probably even better, 6H30 Russian tubes (check pinout is suitable). I just added cathode followers to the output to drive 2 pairs of output tubes. For driving a single pair of output tubes the cathode followers would not be required and you could use the PCB1A boards as the whole front end.
P.S. I seem to recall that I had a problem with 6N1P not giving me quite enough gain.
Cheers,
Ian
I've got a very nice prototype monoblock running using 4 off KT88 in Parallel Push Pull Ultralinear into Hammond 1650T trannies to give 135W.
Frequency response measured at 50W output was 65kHz at the high end and it was flat down to 22Hz at the low end but with some weird distortion setting in at around 18Hz due, I believe, to transformer core saturation. This would seem to stack up pretty well with hammonds claim of full power (120W) bandwidth of 30Hz to 30kHz
If interested then Go here:
http://www.evatco.com.au/project.htm
The 3rd project example down has a picture of the very agricultural prototype, the links for the schematic for the amplifier and the power supply and a link for the designers (me) comments. I did this amp around 2 years ago and rebuilding it to a decent chassis and doing the second channel is sort of gradually moving up the priority list. I also have PAT4006 Toroidal Output Trannies and tried them in place of the Hammond 1650Ts. The hughly higher primary inductance reduced lowe frequency 2nd harmonic distortion dramatically and the nominally 2100:5 impedance ratio compared to the Hammond 1900:4 required a bit more global feedback. Frankly I liked "Classic Tube Amp" sound that the Hammond imparted better than the pristine results from the Plitrons. My hip pocket liked the Hammonds a whole lot better too.
You will see that I used Cursio Audio Engineering (CAE) PCB1A boards for the front end. These boards were intended for upgrades of Dynaco MK3 Amps. The boards have a 6DJ8 (ECC88) cascode diffamp, with a current source tail and a high voltage regulator, These days you could also use 6N1P or probably even better, 6H30 Russian tubes (check pinout is suitable). I just added cathode followers to the output to drive 2 pairs of output tubes. For driving a single pair of output tubes the cathode followers would not be required and you could use the PCB1A boards as the whole front end.
P.S. I seem to recall that I had a problem with 6N1P not giving me quite enough gain.
Cheers,
Ian
Yeah, choke input requires much more voltage. I have a 350-0-350 tube rectified, CLC PS that gives me 425V. I would think that with a hundred more volts to burn 475 to 500 should be possible with tube rectification and cap input. More with SS rectification.
Choke input? Maybe order a custom PTX or check supplier other than Hammond.
Choke input? Maybe order a custom PTX or check supplier other than Hammond.
Hello
I/Dynaco are running the tubes at 480 volt and 70 mA/tube, So You need 300mA and 480Volt + choke drop to each amplifier. Buuut can the 6AN8 drive 4 KT88?
I Use a 400 Vac 350 VA power trafo. Sil diode bridge, and a RCLC smooting, giving 515 volt DC and 2 mV rippel.
If I need more power and KT88, I would build this amplifier: http://www.jogis-roehrenbude.de/Leserbriefe/Michael-Kammerer-Amp/Michael-Kammerer-Amp.htm
Benny
I/Dynaco are running the tubes at 480 volt and 70 mA/tube, So You need 300mA and 480Volt + choke drop to each amplifier. Buuut can the 6AN8 drive 4 KT88?
I Use a 400 Vac 350 VA power trafo. Sil diode bridge, and a RCLC smooting, giving 515 volt DC and 2 mV rippel.
If I need more power and KT88, I would build this amplifier: http://www.jogis-roehrenbude.de/Leserbriefe/Michael-Kammerer-Amp/Michael-Kammerer-Amp.htm
Benny
schmatics
I need to go back to school. Can someone point me in the direction of someone i can call and consult with. I need someone to provide or design the circuit for me.
I want to use the following parts to build a 60 watt per channel and on a single chassi nto mono blocks.
One stereo unit will have one pair kt88 inpush pull for each channel
The out put tramformer per channel will be Hammond 1650p speced for 60 watts.
The filiment and drive transformer will be one Hammond model??? at Vollts???-0-??? and ??? milli amps for boths channels.
I need to have ballanced inputs.
I will be building 3 or 4 stereo amps.
I need 2 for my fourway horn system
I need to go back to school. Can someone point me in the direction of someone i can call and consult with. I need someone to provide or design the circuit for me.
I want to use the following parts to build a 60 watt per channel and on a single chassi nto mono blocks.
One stereo unit will have one pair kt88 inpush pull for each channel
The out put tramformer per channel will be Hammond 1650p speced for 60 watts.
The filiment and drive transformer will be one Hammond model??? at Vollts???-0-??? and ??? milli amps for boths channels.
I need to have ballanced inputs.
I will be building 3 or 4 stereo amps.
I need 2 for my fourway horn system
Sorry for the hijack, but im interested in building two Mark III's and wanted to know a few of things.
- What wattage, besides the specified 1 watt, are the resistors for this build.
- How does this amp sound ?
- Is this a good choice for a noob project ?
- Do I have to build a phono preamp to run with a MMF-5 ?
- If I need a phono preamp, which will you recommend ?
- And just for giggles. At age 6 I almost gave my dad a massive heart attack when he caught me spaceships/rockets (his tubes collection) out of our second story apartment. This was back in the 70's
An externally hosted image should be here but it was not working when we last tested it.
Still need KT88 amd Hammond circuit
Guys Is there anyone out there that has a schematic easy to follow for a KT88 amp with Hammond primary transformer and Hammond out put trany. I want to build 50 to 60 watt per channel amps, push pull kt88. Even if the circuits require push pulls in parrallel is alright. I need model numbers and detailed values possible parts list . If there is none availble please put me in touch with a designer for hire to provide the information.
Guys Is there anyone out there that has a schematic easy to follow for a KT88 amp with Hammond primary transformer and Hammond out put trany. I want to build 50 to 60 watt per channel amps, push pull kt88. Even if the circuits require push pulls in parrallel is alright. I need model numbers and detailed values possible parts list . If there is none availble please put me in touch with a designer for hire to provide the information.
What you specifically asked for...
jbldriven,
Since you don't seem to be getting much help on your specific question and you are from Canada can I RECOMMEND:
1) Purchase "Principles of Power - A practical guide to tube power amplifier design"
by Kevin O'Connor of London Power
NEW CONTACT INFO:
Mailing Address:
London Power / Power Press Publishing
1020 Dawson Road
PO Box 23011
Thunder Bay, Ontario P7B 6P1 CANADA
Phone:
807-473-0952 (11am-6pm, Monday to Friday, Eastern Time)
FAX:
807-939-1324 (anytime - secure for credit card orders)
He also has an email address which I haven't included to save him from being spammer bashed. Check out his web pages here:
http://www.londonpower.com/
Once you have that book in your hot little hand you can EITHER:
2) turn to page 5-28 which describes a 60W HiFi Power Amp using Hammond 1650N Output Transformer and Hammond 278X Power Transformer. Design is 12AX7 diffamp cascaded to 12AT7 diff amp driver to 6550. Just sub KT88 in place of the 6550 - no changes required.
OR
3) turn to page 5-30 which describes a 60W HiFi Power Amp with the same tube compliment as above BUT using the Hammond 1650P as the output. 12AX7 diffamp front end is direct coupled to 12AT7 cathode followers to drive 6550 outputs (once again just substitute KT88 for 6550).
My own preference would be for the page 5-30 version using 1650P - why? because its a little better if you want to mess about with trying Triode Mode or reducing feedback to give a more "live" feel to the amp.
Cheers,
Ian
jbldriven,
Since you don't seem to be getting much help on your specific question and you are from Canada can I RECOMMEND:
1) Purchase "Principles of Power - A practical guide to tube power amplifier design"
by Kevin O'Connor of London Power
NEW CONTACT INFO:
Mailing Address:
London Power / Power Press Publishing
1020 Dawson Road
PO Box 23011
Thunder Bay, Ontario P7B 6P1 CANADA
Phone:
807-473-0952 (11am-6pm, Monday to Friday, Eastern Time)
FAX:
807-939-1324 (anytime - secure for credit card orders)
He also has an email address which I haven't included to save him from being spammer bashed. Check out his web pages here:
http://www.londonpower.com/
Once you have that book in your hot little hand you can EITHER:
2) turn to page 5-28 which describes a 60W HiFi Power Amp using Hammond 1650N Output Transformer and Hammond 278X Power Transformer. Design is 12AX7 diffamp cascaded to 12AT7 diff amp driver to 6550. Just sub KT88 in place of the 6550 - no changes required.
OR
3) turn to page 5-30 which describes a 60W HiFi Power Amp with the same tube compliment as above BUT using the Hammond 1650P as the output. 12AX7 diffamp front end is direct coupled to 12AT7 cathode followers to drive 6550 outputs (once again just substitute KT88 for 6550).
My own preference would be for the page 5-30 version using 1650P - why? because its a little better if you want to mess about with trying Triode Mode or reducing feedback to give a more "live" feel to the amp.
Cheers,
Ian
Re: kt 88 schematics
I think all the answers that you need are in this thread. If you are in fact looking for 'tried and true', build up a Dynaco Mark 3.
The only Hammond power trannies that would work is the 278x if you are running a tube rectifier, or the 278cx if you are not.
Triode Electronics (triodeelectronics.com) has everything that you need for a Dynaco... right down to pre-punched chassis, boards and even mods and upgrades. They have the original reproduction trannys, but you seem set on Hammond, so use those instead.
jbldriven said:
I think all the answers that you need are in this thread. If you are in fact looking for 'tried and true', build up a Dynaco Mark 3.
The only Hammond power trannies that would work is the 278x if you are running a tube rectifier, or the 278cx if you are not.
Triode Electronics (triodeelectronics.com) has everything that you need for a Dynaco... right down to pre-punched chassis, boards and even mods and upgrades. They have the original reproduction trannys, but you seem set on Hammond, so use those instead.
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