Manzamp with KT88s

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MHProd
Posts: 168
Joined: Tue May 07, 2013 6:47 pm

Manzamp with KT88s

Post by MHProd »

I want to build a Manzamp with a pair of KT88.

The OT i have is an old and massive Triad 50W with 3K3 pri.

The amp will have a GZ34 rectifier and I'm not 100% sure what PT i should get...

This one seems ok: http://www.classictone.net/40-18094.html ...but I'm not sure the 200ma rating is enough. I'm shooting for something around 430V on the plates. Another option is a TW PT where the current will be more but I'll probably be around 380V on the plates with the 300V B+.

After doing some research on the forum, it looks like it'd be a good idea to drop the screen voltage so it's well below the plate voltage. What resistor value should I use after the choke to accomplish this?
talbany
Posts: 4696
Joined: Tue Mar 28, 2006 5:03 am
Location: Dumbleland

Re: Manzamp with KT88s

Post by talbany »

Here is an informative discussion on running both 6550's and KT 88's you want to read through.
Hopefully will answer some questions you have.

https://ampgarage.com/forum/viewtopic.php?f=4&t=32487

Tony
" The psychics on my bench is the same as Dumble'"
MHProd
Posts: 168
Joined: Tue May 07, 2013 6:47 pm

Re: Manzamp with KT88s

Post by MHProd »

Hmmm, I have a really nice sounding pair of KT88 and it’s not about the amp having to produce 75w... my understanding is keeping the screens close to the plate voltage will create less power. I’m ok with that if it’s just a power thing.

How about the PT though? 200ma enough or?
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