World-Designs-Forum (
-   WAD General (
-   -   WAD 300B mono blocks (

Daft Fader 9th October 2017 05:20 PM

WAD 300B mono blocks
Hi everyone.

I am trying to locate all PDF documentation on this product.
I am also looking to find a pair of power switches - ideally with the cap tops.

Could anyone help me? Thanks.

Richard 10th October 2017 09:11 AM

Re: WAD 300B mono blocks
1 Attachment(s)
Hello and welcome!

Which monoblocs are they, Push Pull or Parallel Single Ended? (Both look the same externally.)

Drop Matthew an email and preferably a picture of your power switches. IIRC they are simple rotary on/off on the front panel and the switches and chrome knobs should be same as still used on WD PSU3,

Be careful working inside if you're not experienced as there's 500V in there.

Daft Fader 10th October 2017 12:54 PM

Re: WAD 300B mono blocks
Hi Richard.

Thanks for your reply.

I have half of what seems a mono bloc instruction manual with 300B PSE so it looks parallel single ended.

The previous owner bypassed the on off switch to always on - apparently because he was running his whole rig through a power conditioner so powered on the whole rig at the socket.

So with this in mind, may I ask a further couple of questions?

Where can I get and how much are the rotary power switches and caps?
What would you say the current value is for a pair of average condition but fully Woking mono blocs (as I need to know what they are worth before investing anymore in these units).

Many thanks again.

Richard 10th October 2017 02:15 PM

Re: WAD 300B mono blocks
Hi again,

Do you have the valves? A quick check is that,
300BPP used 6au6, 5687, and 2x 300B
300BPSE used 6au6, ECC82, and 2x 300B

If no valves you'll need to check the circuit inside.

Are the switches not there at all? Seems strange the previous owner didn't just leave them switched on at the switches or hardwire them inside.

Anyway, what do you mean by the caps? Not being pedantic but we use caps as short for capacitors so best if we know what you want. Do you mean the chrome knobs for the switches?

Matthew will be able to supply the switches themselves for a few pounds as I've just had a look at a spare one and they are the WD PSU3 ones. The knobs (if it is them you need) will be quite expensive as they are solid with mirror chrome finish so you'll need to ask him.

I sold the pair of PP in the pic maybe 5 years ago for about £550 iirc and the PSE go for similar money. Valves are expensive though so the price will vary accordingly :thumbsup:

Daft Fader 10th October 2017 02:31 PM

Re: WAD 300B mono blocks
Thanks mate.

Yes all valves present and correct (I am listening to them as we speak with a bit of old soul).

I will undo the front later and have a look - he may had just capped them off and hopefully the switch is behind it.

You be as padantic as you like! I appreciate your help. Yes indeed it is the knob tops I may also need.

I will give him an email once I know what’s inside!

All the best and thanks again. I hope you won’t mind me tapping you for more info if I get stuck.

Great site! Thanks again.

Daft Fader 10th October 2017 08:50 PM

Re: WAD 300B mono blocks
Hello. Another question please?

I have been running the amps for several hours now and the rear transformers are hot but the front are cold. If this correct?

Also - what is the maximum input signal as my phone only provides 600mw from the headphone output.


bob orbell 11th October 2017 08:02 AM

Re: WAD 300B mono blocks
Your first question is the transformers that are getting hot are the mains power transformers, this is normal and after some hours of use may be quite hot. Sorry, I don't understand your second question, :confused:. BOB Ah, are you running your phone into the 300B,s? I think the input for these depends on the model, and if you have the feedback switched or not, but I will let Richard or someone else comment.

Daft Fader 11th October 2017 08:07 AM

Re: WAD 300B mono blocks
On both amps - Of the 2 chrome top transformers, those towards the back of the amp get very hot and those at the front stay cool - even after 5 yours of use. Is this normal?

A friend told me that these amps acheive 0Db signal with a 2v input. Is that correct?


Richard 11th October 2017 10:16 AM

Re: WAD 300B mono blocks
Hello again, yes, as Bob says, the back transformers near the terminals are the mains power ones and will run hot after a few hours. Put them on an open shelf for ventilation.

Yes a phone should be fine as the amps are 1V sensitive with feedback switched in and 380mV without and have a high 100K impedance. Headphone outputs can vary as they are designed typically to drive a lower load than line level which is more standardised. The phone's output may be expressed in mW as headphones have different impedances and sensitivities so the voltage may change into those differing loads.

(Next step up would be a laptop running FLAC files via Foobar or streaming from the web into a USB DAC then your amps.)

When my lad went to Uni 10 years ago I sorted an old Jap amp and a pair of bookshelf speakers for him to take and he used his phone plugged via a stereo 3.5mm to RCA cable (Maplins) straight into the AUX amp input. He still uses it that way in his room when he comes home these days :thumbsup:

Daft Fader 11th October 2017 12:01 PM

Re: WAD 300B mono blocks
Thanks ever so much for putting up with my stupid questions guys. Much appreciated.

I have ordered some parts from Matthew Snell.

I asked him for as many PDF files as possible on these products and he has kindly allowed me to go to this forum to ask fellow members should they have any you could email me?

Thanks again.

Daft Fader 11th October 2017 02:09 PM

Re: WAD 300B mono blocks
Thanks Richard.

I will give them a go using my digital mixing console in my studio.

All the best and thanks for your comments and advice.

Richard 11th October 2017 02:28 PM

Re: WAD 300B mono blocks
You're welcome. The studio sounds interesting. Always good to hear about such stuff :) If you send me an email (click Richard top left) I can reply with the pdf build sheets :thumbsup:

Richard 12th October 2017 09:51 AM

Re: WAD 300B mono blocks
Just thinking, if you've a later phone with card storage and OTG/Micro usb it might be worth looking at an external DAC which should give better quality than the phone's analogue out. Run android Foobar app as the music player and you'd get around 60 FLAC albums on 20GB of the card or several times that in MP3s. Anyone done this and how good is it into a hifi?

All times are GMT +1. The time now is 08:25 PM.

Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright World Designs