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Change my 8417's Quicksilvers to this?

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Burnedfingers

Member
Joined 2002
A few years back I owned a pair of Quicksilver KT88's in addition to my sets of 8417's. I took the back off and made this schematic that I will try to post. Unfortunately I sold the KT88's but I rather liked the sound of them. It was pleasing. I am thinking of redoing a pair of my 8417's to this circuit and would like your input.

Thanks,
Joe
 

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Burnedfingers

Member
Joined 2002
Giaime

The output transformers are the same except the KT88's didn't have a 16 ohm speaker tap. They are both 4300 ohm impedance.

The 8417 is a great sounding tube and right now my 8417's will work with 6550's,KT88's or 8417's with just a rebias. They are rock solid with any 8417 I thow into them. They are just costly to purchase since they aren't made anymore.
 
poobah

poobah

Member
Joined 2005
Well,

The Leslie speaker amp I am rebuilding has 6550's (almost KT88) ... so yeah, I like them. They growl like hell. Oddly though, many of the best hifi designs (from reading ALONE) used 6550's.

With the SE craze in full swing right now... noone seems to be talking much about PP.

I do know, again from reading, that the new "tung sol" 6550 is getting pretty goods reviews... in terms of all that stuff we make fun of though!

I am getting the itch, real bad, to build an hifi tube amp...

:smash: :smash: :smash:
 
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BTW

Member
Joined 2002
Hi Burnedfingers,

Just a few suggestions for you to try out..
As mentioned earlier try changing the feedback ie try reducing the amount of feedback, this should make the sound sweeter..
Next if your spks aren't too power hungry try wiring the 8417 in triode, PP triode wired amps can sound very nice ... :)
 
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Burnedfingers

Member
Joined 2002
Thank you for the replies. I will try to restate what I want to do.

I want to rewire a pair of 8417 amps to the schematic I posted in my number 1 post. As you can see the front end on the KT88 amp is quite different than that of the 8417 amp.

I am wanting to know your feelings about the schematic in my number 1 post. Would it be worth it? Changes that you might suggest.

Post number one contains the KT88 schematic. Post number two shows the 8417 schematic.

Thanks
 
SY

SY

Ex-Moderator
Joined 2002
SYclotron.com
Yeah, the front end looks odd, especially the feedback arrangement. I'm particularly suspicious since the first stage has balanced plate resistors and the second has unbalanced resistors. The feedback seems to be common mode.

Could it be that the first stage's sections are actually in parallel? That would make things more sensible to me.
 
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