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Old 15th October 2004, 12:24 PM   #11
ICARE is offline ICARE  France
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Join Date: Mar 2003
Location: MADRID
Look here:

Address:
C/Laguna 10, 28923 Alcorcon, Madrid, Spain

Telephone: (+34) 91-4862800
Fax: (+34) 91-6414597
Email: info@letusa.es

http://www.letusa.es/distribuidores/FX.html

They are distribuidor for FOSTEX, but they donīt have Speakers, maybe you can call them and they can order some of them...

J-Y
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Old 21st October 2004, 10:34 AM   #12
Cassiel is offline Cassiel  Libya
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Hi again,
i've been kind of busy...thanks for the replies.

Mikael i'm gonna follow your schematic(quite simple) but what about the power supply? Do you use diode or tube rectification?
Diodes are cheaper but some people say they can hear the difference...i dunno.
Another question. What OT's do you recommend me? It must have 3 taps right? I do use a Hammond but only has 2 primaries not 3 ...is that an ultraliniar connection, the 2nd grid going to the center tap?
Thanks for the link.

Icare, very kind, Letusa don't work with drivers they told me to ask them in Germany. Your speakers are impressive...yes i have heard about bass deficiencies in tube amps...seems they generally lack in that area, my bass is ok in my amp. Right now i'm out of town but i will send you an email when i do get back.
I must listen to those speakers.
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Old 21st October 2004, 11:56 AM   #13
ICARE is offline ICARE  France
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Thanks,

For the hamond I personaly think they are too expensive for the quality. I make mine here http://magnetic.com.free.fr/
They are really professional and make really good C-CORE output transformer, and the best is you can ask for you want.

For listening my speakers NO PROBLEM, you are welcome, just send me a e.mail. They are perfectly for a small room like my apartment.

See you
J-Y
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Old 26th October 2004, 03:42 PM   #14
Cassiel is offline Cassiel  Libya
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Hi Icare,


Your email address is not available so i cannot email you; as for the OT's ,i agree with you,Hammond's are nothing out of this world but they were here in Spain so i went for them. Hurry sometimes matters.

Out of town again so no problems about not getting your email, but please do change the configuration or else....i won't hear anything.


Cheers,


Stalker
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Old 26th October 2004, 05:04 PM   #15
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I'm currently building a KT88 amp. Picture attached in following posts.

I'm using a schematic from Andrea Ciuffoli below. This is a push-pull idea, but I'm using a similar idea. I replaced the E182CC with a 6c45pi, running at 10mA with the LL1660, with similar plate voltages.

On the secondary side of the LL1660, I don't use push-pull. Instead, I use SE. Refer to the other schematic from Ciuffoli for a SE circuit on the secondary side of the LL1660. You can easily replace the KT90 with a KT88 with very minor modes (if any at all). I have Plitron transformers.
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File Type: gif amp_kt88_cf1.gif (15.6 KB, 1545 views)
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Old 26th October 2004, 05:06 PM   #16
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Here's what it looks like on the secondary. Use a KT88 instead:
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Old 26th October 2004, 05:08 PM   #17
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And here's the glowing KT88s. You can't see the 6c45pi or the LL1660 in this picture.
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Old 26th October 2004, 05:19 PM   #18
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I also tried putting the tube BELOW the output transformer. You can do it either way. By putting the tube below the output transformer, you have the option of running Triode, Pentode, or UL (if your transformer has a UL tap). I also played with using the output transformer's secondary as cathode feedback on the KT88.

Putting the tube on TOP (cathode follower), you are required to run the KT88 in Triode mode (this can be good). You also get the benefit of cathode feedback via action of the output transformer's primary (which can also be good). The drawback is the input signal to the KT88's grid must be HUGE to compensate for (1) the KT88's triode mode, and (2) the gigantic cathode feedback action of the transformer's primary.

What works for you, works against you. Here's the paradox: the output stage is more linear in this configuration, but the driver stage is pushed harder, creating distortion in the driver stage. By making the output stage more linear, it's forced more of the work onto the driver!
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Old 29th October 2004, 10:37 AM   #19
Cassiel is offline Cassiel  Libya
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Hi,
your amp looks fine Kashmire but i won't be using two transformers. Andrea Ciuffoli's designs are worth trying out though, one day i will do an OTL designed by him.

Cheers ,

Stalker
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Old 29th October 2004, 12:56 PM   #20
Sherman is offline Sherman  United States
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Quote:
Originally posted by Mikael Abdellah
I have built a wonderful SE KT88-amp.

http://213.67.45.220/se_kt88.gif

It's REALLY simple to build. I'm unsure how it would work with headphones, but maybe someone else can answer that for you.

Amazing. In looking for an amp to build this winter I had decided to go with a simple ECL82 design. Then I saw this one! Just as simple as the ECL82 (well, almost, two tubes here) and I think it would be a nicer sounding amp as well.

I think this may be my project for the winter! Thanks for posting it Mikael!
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