Re: Where to buy James transformers now?
Too bad about Euphonia. Their prices were good and at least in my case so was their service. I placed my order for the transformers and they were at my door in three days.
As for power transformers- the B+ required for Mikael's amp is 400 V. Biased according to the schematic each KT88 will draw 75mA and the 6N1P will draw 8 mA or so. That is 83 mA per side. Allowing a margin for safety your PTX should be able of delivering 190 mA or so.
In the James line JS-9610, JS-9611 or JS-9612 would work, though you may have to burn some excess voltage. Use the 380V taps.
I used Hammond for the PTX (forget which model) that is 350-0-350. I built monoblocks so I am only pulling 90mA or so from the power supply for each. I am using tube rectification with a 5U4-G into a 40uF-8 Hy-100uF filter. My mains voltage runs a bit high, 123-125VAC and my B+ with that setup is 425. My bias on the KT88 is 82mA.
Curly Woods said:It seems that Euphonia is no long selling anything at all as of October 17th...
Does anyone have a suggestion on what James power transformer would be proper for Mikael's KT88SE amp? I like the look of the potted transformers
Too bad about Euphonia. Their prices were good and at least in my case so was their service. I placed my order for the transformers and they were at my door in three days.
As for power transformers- the B+ required for Mikael's amp is 400 V. Biased according to the schematic each KT88 will draw 75mA and the 6N1P will draw 8 mA or so. That is 83 mA per side. Allowing a margin for safety your PTX should be able of delivering 190 mA or so.
In the James line JS-9610, JS-9611 or JS-9612 would work, though you may have to burn some excess voltage. Use the 380V taps.
I used Hammond for the PTX (forget which model) that is 350-0-350. I built monoblocks so I am only pulling 90mA or so from the power supply for each. I am using tube rectification with a 5U4-G into a 40uF-8 Hy-100uF filter. My mains voltage runs a bit high, 123-125VAC and my B+ with that setup is 425. My bias on the KT88 is 82mA.
Thank you Sherman
Thank you Sherman. I too want to build these amps as monoblocks. This is more of curiosity for me. I am going to build a set of full range speakers using a Fostex driver and wanted to try a SET amp other than the 300's for the output tubes. 4 to 5 watt output will be fine for what I hope to achieve.
Thanks again for the help!
Thank you Sherman. I too want to build these amps as monoblocks. This is more of curiosity for me. I am going to build a set of full range speakers using a Fostex driver and wanted to try a SET amp other than the 300's for the output tubes. 4 to 5 watt output will be fine for what I hope to achieve.
Thanks again for the help!
I have been hearing about Mikael Abdellah's KT 88 amp for a few months, but I can not get the links to work at home of at work.
Originally posted by Mikael Abdellah
I have built a wonderful SE KT88-amp.
http://213.67.45.220/se_kt88.gif
http://213.67.45.70/tube/
http://213.67.45.70/se_kt88.gif
All of these come back " Cannot find server or DNS Error ".
Is there any other source for these schematics, I am getting curious?
Originally posted by Mikael Abdellah
I have built a wonderful SE KT88-amp.
http://213.67.45.220/se_kt88.gif
http://213.67.45.70/tube/
http://213.67.45.70/se_kt88.gif
All of these come back " Cannot find server or DNS Error ".
Is there any other source for these schematics, I am getting curious?
Re: Thank you Sherman
As I said my B + is higher than the schematic, but not dramatically so. My KT88s are biased a bit higher as a result. Measurements indicate about 7.5 watts before clipping so you should have no problem getting 4.5 or 5 watts. My harmonic distortion meter is currently inop so no measurements there (but it sounds good).
I've used the amps with some DIY line arrays at about 95dB efficiency, Advent /1 (about 87dB IIRC) and Dynaco A25s (more efficient than the Advents but not sure of the actual rating). The amps are able to drive them all to quite loud levels.
Curly Woods said:
As I said my B + is higher than the schematic, but not dramatically so. My KT88s are biased a bit higher as a result. Measurements indicate about 7.5 watts before clipping so you should have no problem getting 4.5 or 5 watts. My harmonic distortion meter is currently inop so no measurements there (but it sounds good).
I've used the amps with some DIY line arrays at about 95dB efficiency, Advent /1 (about 87dB IIRC) and Dynaco A25s (more efficient than the Advents but not sure of the actual rating). The amps are able to drive them all to quite loud levels.
Thanks for posting the schematic. It is very similar to my SimpleSE. I use a 12AT7 input tube, and often use a CCS for a plate load.
I have a slightly biased opinion, but I (and my friends) think that it sounds awesome. The 5 k load gives better sound than the usual 3.6 K load, Especially when you crank the B+ up into the near meltdown zone (525 volts), and use big transformers. EH KT88's seem to be happy with this abuse, and give me 12 to 15 watts in UL mode.
I have a slightly biased opinion, but I (and my friends) think that it sounds awesome. The 5 k load gives better sound than the usual 3.6 K load, Especially when you crank the B+ up into the near meltdown zone (525 volts), and use big transformers. EH KT88's seem to be happy with this abuse, and give me 12 to 15 watts in UL mode.
KT88 SE amp project
Hello
I want to build a KT88 SE amp.
Do you think these amp would be a good project to give a try?
It look nice to me but I'm familiar with solid state amps.
I just want to have a good tube amp so sometimes I can listen a tube sound.
Here is the amp, these about 12W
KT88SE Roehrenverstaerker, von Michael Dieckmann
Also there is a higher power parallel KT88 SE 27W.
KT88-PSE-Amp, von Christoph Lassok
Actually to me enough the single tube version to but I'm open for any advise.
Thank you
Greetings gabor
Hello
I want to build a KT88 SE amp.
Do you think these amp would be a good project to give a try?
It look nice to me but I'm familiar with solid state amps.
I just want to have a good tube amp so sometimes I can listen a tube sound.
Here is the amp, these about 12W
KT88SE Roehrenverstaerker, von Michael Dieckmann
Also there is a higher power parallel KT88 SE 27W.
KT88-PSE-Amp, von Christoph Lassok
Actually to me enough the single tube version to but I'm open for any advise.
Thank you
Greetings gabor
Hello
I want to build a KT88 SE amp.
Do you think these amp would be a good project to give a try?
It look nice to me but I'm familiar with solid state amps.
I just want to have a good tube amp so sometimes I can listen a tube sound.
Here is the amp, these about 12W
KT88SE Roehrenverstaerker, von Michael Dieckmann
Also there is a higher power parallel KT88 SE 27W.
KT88-PSE-Amp, von Christoph Lassok
Actually to me enough the single tube version to but I'm open for any advise.
Thank you
Greetings gabor
I hope I don't get banned for posting this, and I believe I am following the rules here, but I do have a kit for sale that is a variation on Mikael Abdellah's SE KT88 if you might be interested. A few people have built this kit already. It is a complete kit including pre-punched chassis and transformers. You can read about it in my signature link.
Scott
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