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Old 12th Aug 2018, 1:50 pm   #1
recordplayer
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Default Watkins Westminster valve amp

Hi, I am repairing a Watkins amp - even though it works I am going to change all the Hunts caps, and the electrolytics, and any resistors that are out of tolerance. I think it dates back to about 1956 and the valve line up is: 2x ECC83, 1X 6AQ5, 2XEF86, 1XEL90, 1X EZ80 which I will also check out. Does anyone have the schematic / circuit diagram or know the exact model - see pics.
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Old 12th Aug 2018, 2:58 pm   #2
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Default Re: Watkins Westminster valve amp

I can't find anything about that chassis that's shown for the Westminster, but I'm no expert.

Lawrence.
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Old 12th Aug 2018, 3:18 pm   #3
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Default Re: Watkins Westminster valve amp

That's a lot of valves for a single ended EL90 amp. Maybe they are used for effects or the OP has the line up wrong?
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Old 12th Aug 2018, 3:29 pm   #4
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Default Re: Watkins Westminster valve amp

I think a 6AQ5 is an equivalent to the EL90. Which, given one of each in the lineup, suggests it could be a push-pull output stage using those 2 valves
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Old 12th Aug 2018, 3:44 pm   #5
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Default Re: Watkins Westminster valve amp

Not found a schematic but this page gives more details about the Westminster models.

http://www.vintagehofner.co.uk/brita...stminster.html

Al
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Old 12th Aug 2018, 3:51 pm   #6
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Default Re: Watkins Westminster valve amp

The output transformer looks like a Radiospares Hygrade…?

Lawrence.
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Old 12th Aug 2018, 7:23 pm   #7
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Default Re: Watkins Westminster valve amp

Again no schematic but the third picture in post #1 looks identical to this one on the site mentioned by Alistair D

http://www.vintagehofner.co.uk/brita...er/west21.html
c1956 WATKINS WESTMINSTER AMPLIFIER COURTESY OF MICHAEL KERR, ESSEX, ENGLAND:

and the internals:-
http://www.vintagehofner.co.uk/brita...er/west19.html
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Old 12th Aug 2018, 7:23 pm   #8
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Default Re: Watkins Westminster valve amp

Edward , with all due respect the valve line up is correct - when I said I would check the valves I meant the condition of the valves not the line up . Yes there are a few valves but they are the right ones - if you read my post it says the amp is working - so they can't be the wrong valves !
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Old 12th Aug 2018, 7:35 pm   #9
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Default Re: Watkins Westminster valve amp

Quote:
Originally Posted by ms660 View Post
The output transformer looks like a Radiospares Hygrade…?
Many of the early Watkins amplifiers used RadioSpares transformers.
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Old 12th Aug 2018, 7:45 pm   #10
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Default Re: Watkins Westminster valve amp

Cheers, it was the colour on the label that made me think it might be RadioSpares, followed by the 6 tags on one side.

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Old 12th Aug 2018, 8:00 pm   #11
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Default Re: Watkins Westminster valve amp

Hi , yes I checked vintage Horner , I guess the 1956 one is the closest to mine - will work off that schematic - very similar to mine
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Old 12th Aug 2018, 8:54 pm   #12
Edward Huggins
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Default Re: Watkins Westminster valve amp

Quote:
Originally Posted by TonyDuell View Post
I think a 6AQ5 is an equivalent to the EL90. Which, given one of each in the lineup, suggests it could be a push-pull output stage using those 2 valves
Arghhh - I missed this. You're right. No matched pair here then. I guess it will sound similar to 2 x 6V6s in PP. Not many early UK Guitar amps used these.
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Old 12th Aug 2018, 9:25 pm   #13
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Default Re: Watkins Westminster valve amp

Hi,

According to the r-type valve site the EL90 design is the classic 6V6 squeezed into the tiny B7G envelope!

Maybe they were trying to get near the Fender amps of the time which used 6V6's, but it was probably more like they were plentiful and at good price at the time

From memory the PYE HF5/8 used a pair of EL90's.

Terry
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Old 12th Aug 2018, 9:32 pm   #14
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Default Re: Watkins Westminster valve amp

Quote:
Originally Posted by Edward Huggins View Post
... No matched pair here then ...
They could be (apart from the ink). The valve museum entry for the EL90 http://www.r-type.org/exhib/aad0125.htm shows that Brimar made them and printed either EL90 or 6AQ5 on the outside, presumably in response to what their bulk customers asked for.

Cheers,

GJ
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Old 12th Aug 2018, 9:34 pm   #15
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Default Re: Watkins Westminster valve amp

This one?
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Old 12th Aug 2018, 10:08 pm   #16
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Default Re: Watkins Westminster valve amp

6AQ5s were very common in Australia. They are a 6V6 in a seven pin bottle but have maximum (recommended) HT of 250 volts. They sound delicious, just like a 6BW6, 6V6, 7C5 or 6AQ5/EL90. It will be a very nice little amp. In theory its good for about 10 watts RMS.

Joe
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Old 13th Aug 2018, 6:44 am   #17
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Default Re: Watkins Westminster valve amp

Your amp looks exactly like the one in the main pic on the WEM site -
http://www.vintagehofner.co.uk/brita...stminster.html it has the same bare patch on the corner and the dinks in the speaker grill match up.

Can't find a schematic but yours looks to be the same as this one - http://wem-owners.com/combos/westmin...tminster-1968/ which gives the date as 1959, so it's a very early one.

The schematic in post #15 looks to be about the nearest you'll find for the OP stage. I'd guess the EF86's are a mic preamp section. does it have a tremelo?

Andy.
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Old 13th Aug 2018, 7:31 am   #18
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Default Re: Watkins Westminster valve amp

Ah - the late great Charlie Watkins; WEM stands for Watkins Electronic Music. Died in 2014 at age 101. Around 20 years ago I fixed up a Dominator Bass cabinet for my son, and Watkins was still answering the phone well into his 80's!

You'd need a purple phone to get him now, alas.

Craig
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