K5881 Valve Amplifier

[Greg.]

Hello ian2to and welcome to the forum. Yes, I can help with the information you need but first I need to know a bit more about your kit.

There were three different 5881 kits produced by WAD. If you are not sure which kit you have, the versions are easily identified by the use of different first and second valves (V1, V2)

1. K5881 Mk1, V1 EF86, V2 ECC83
2. K5881 Mk2, V1 ECC83, V2 ECC83
3. K5881 PSE, V1 7025, V2 6922

Do you have the build instructions for your kit? These include the details you need. Once you have identified the kit you have, if you need a copy, Private Message (PM) me with your email address and I will send a copy to you.

[vinylspinner]

Welcome ian2to, you may need to make a few more posts to be able to receive/send private messages on this forum, at least 5 posts are required.

The 5881 is a nice amp, I have owned the MK1 and MK2 versions.

Nigel

[ian2to]

Originally Posted by ian2to

hello!
I am posting from Japan at first time..
I bought k5881 kit 22years ago.but
I still do not buid kit yet.
and my wife through away resistor and capasitor.
Now I try building this again.
I have to prepare parts as registerand capasiter.
but all resistor wattage is not mentioned in instruction
docu.Is there person who can give me wattage info
for all resistor ?

[quote=RichW;85371]This is my first post so I would like firstly to say hello to all the forum members.
I work in electronics but I am ashamed to say that the use of valves were predominately over when I did my training many years ago.
So I decided to buy a WAD K5881 amplifier with the intention of learning something new or should I say old and use it to resurrect my interest in HiFi.
I believe the amplifier is a MK1 push pull.
Can anyone please provide me with a circuit diagram for the MK1 and MkII versions?


Thanks Richard[/QUOTE


hello!
thank you for your suport.
my kit is no1 ecc83&ef86.
and
I have instructions.but some resistor does not
have wattage.therefore I couldn't buy resistor by My side in Japan.
mybe you know such resistor wattage without no explanation.

[ian2to]

Originally Posted by Greg.

Hello ian2to and welcome to the forum. Yes, I can help with the information you need but first I need to know a bit more about your kit.

There were three different 5881 kits produced by WAD. If you are not sure which kit you have, the versions are easily identified by the use of different first and second valves (V1, V2)

1. K5881 Mk1, V1 EF86, V2 ECC83
2. K5881 Mk2, V1 ECC83, V2 ECC83
3. K5881 PSE, V1 7025, V2 6922

Do you have the build instructions for your kit? These include the details you need. Once you have identified the kit you have, if you need a copy, Private Message (PM) me with your email address and I will send a copy to you.

hello!
thank you for your suport.
my kit is no1 ecc83&ef86.
and
I have instructions.but some resistor does not
have wattage.therefore I couldn't buy resistor by My side in Japan.
mybe you know such resistor wattage without no explanation.

[Greg.]

All resistors in the Mk1 are rated at 0.25W apart from the 4.7K and 220K which are 2W, and the 560R which are 7W.

As you need to buy your components, you might like to consider building it as a Mk2 as this upgrade was introduced to bring a cleaner and more transparent sound. Apart from the components you need to buy anyway, the only extra cost would be for two more ECC83 valves.

If you would like to do this, I can send you the Mk2 instructions which include the schematic diagrams and the parts list. I just need your email to forward the file to you. You can send that to me by Private Message.

[ian2to]

Originally Posted by Greg.

All resistors in the Mk1 are rated at 0.25W apart from the 4.7K and 220K which are 2W, and the 560K which are 7W.

As you need to buy your components, you might like to consider building it as a Mk2 as this upgrade was introduced to bring a cleaner and more transparent sound. Apart from the components you need to buy anyway, the only extra cost would be for two more ECC83 valves.

If you would like to do this, I can send you the Mk2 instructions which include the schematic diagrams and the parts list. I just need your email to forward the file to you. You can send that to me by Private Message.

hello!Ｄear Geag
thank you for suport.I understood wattage.
how much is 2more ecc83？
My Mail naruishik@docomo.ne.jp

[John Caswell]

Greg wrote
"and the 560K which are 7W."
WRONG it is the 560R which are on the cathodes of the 5881 valves which are 7Watt.
I also suggest that you build the unit as per your valve specification see what you think of it and if you don't like it then try the different version.

John

[Greg.]

Thank you for the correction of my Typo, John. I have corrected my original post.

To confirm, R15/16 are 7W 560R.

I will email the Mk2 instructions and the upgrade from Mk1 to Mk2 instructions. You could then upgrade at a later date as John suggests if you want to try it.

ECC83 are available here at World-Designs. £14 each (2128 Japanese Yen)
http://www.world-designs.co.uk/valves.htm

I expect you can find a supplier in Japan.