Hoping to build a pair of 807 based Mono Blocks on a budget, looking for schematics

[Diabolical Artificer]

I was thinking of doing a class AB PP design, but the single ended designs seem simpler and easier to understand for a first build.

A single ended design might seem simpler, but there isn't that much more complexity to a PP design. See the Williamson 807 PP amp attached. BTW, the power supply can be simplified by using a bridge rectifier and bigger caps.

Before you build your amp what speakers are you going to use? If you have "normal" speakers, IE 2/3 way of a sensitivity around 86 dBA, a single ended triode strapped amp of around 5w is going to struggle to drive them. Your room size will make a difference too.

Also what source are you using? CD/MP3 player? Some older design's will be over driven by modern line level sources like these.

As advised earlier, make a list of requirements and whatnot, it'll help you make up your mind.

Andy.

 

[Mike52787]

My audio sources will be from a turntable (I have a tube preamp I will be using) and my computer through a external DAC. The speakers I will be most likely using with these amps is a pair of KLH 5s I restored a few months back. My room is rather small, I think it's about 12'x12'.

 

[wa4htz]

Mike, search this forum for the "6L6GC AB2 Amp" thread for another suggestion. The thread is the complete process of designing the amp and the original poster was very happy with the end result. George (Tubelab) had a lot of input in the development of the input, phase splitter, and driver stages (uses 6SN7s) and is currently selling a circuit board of a slightly updated version of it over in the Tubelad forum in the vendor area. You might have to back off on some of the voltages a bit in the output stage for 807s (basically a 6L6GB, as others have said) so you don't bust the specs too bad. With 50 Watt Edcor CXPP 6600 Ohm transformers this could be a nice amp for not TOO much cash and should drive those KLHs nicely. Hope this helps.

Ken

 

[Mike52787]

Thank you! I read up on that thread and it seems to be a perfect design for what I have and what I would like to build. I'll make the necessary changes to switch it over to 807s, and update this thread then. Thank you all for all the help 😀

 

[lcsaszar]

Here is my 807 monoblocks photo gallery, schematics included

 

[samhill]

As someone else mentioned as you have four 807s here are some 807 Williamsons from the golden age. I think if you follow their layouts and wiring and use UL it should all work out. I set all these links aside as I plan to try one of these out soon. BTW No real need of dual chassis if you are not using a choke input. Google image 'Radio Craftsmen 500' if you are curious.

http://oestex.com/tubes/mus_amp .pdf
https://dalmura.com.au/static/Gilding the Lily - July 1952 - Audio.pdf
http://www.technicalaudio.com/pdf/G...Linear_Williamson_Amplifier_w_A-8072_xfmr.pdf
https://dalmura.com.au/static/A515.pdf
https://www.updatemydynaco.com/HistoricDocuments/WilliamsonAmplifierKeroes.pdf
https://dalmura.com.au/static/Radio-News-1953-02.pdf

Here’s something contemporary and almost a kit:
http://www.pmillett.com/807pp_amp.htm

and: there's a build on DIY "T-Rex" that's a Williamson with fairly cheap Edcor transformers, apparently it worked well. No reason you couldn't adapt it to 807s, save a little on smaller xformers too. My KT88 Williamson Amp Build