Pye Black Box restoration.

[nicey1977]

Hi everyone,

I am new to this forum and to vintage hi fi in general so please be kind.

I have recently taken apart a couple of Rotel 301As and a Marantz TT333 that I picked up from a bootfair for small change, gave them a good clean inside and buffed out the outside and got them both working fine which has now got me hooked on this old gear but I think I lucked out with those items and now have a Pye Black Box which I am looking to restore to its former glory.

It is a Black Box with Monarch deck and powers up with the light and the mechanism seems to work OK but the sound is poor, very buzzy and seems just too loud and distorted.

The cartridge I cannot identify but it has 4 pins three of them are wired (two pins wired to one wire) and it has a flip over stylus with ST12 LP.S on both sides.

I have played a record on it and it doesn't sound good and skates very easily.

The turntable mat was also very brittle and snapped as I tried to lift it so I will need a nice new rubber mat to finish it off, where do they come from?

I am confident that if I follow the instructions on the forum I can take this thing apart and clean it and check the valves but I am not confident of cartridge identification, parts purchasing and lastly what I really want to do and this is add a line in through the back and use it also as an ipod dock, is this possible?

Many thanks for any help in advance.

Gary

[nicey1977]

One thing to add is that the internals have an EZ80 and two ECL86 valves which seems different than the other Black Boxes I have read about within these forums.

['LIVEWIRE?']

A quick check in the 'Vintage Radio Service Data Downloads' section reveals five different PYE Black Box Valve record players (BBH to BBHS) each made in Mk1 and Mk2 versions.

I have at different times, repaired three different models. I don't know which has the ECL86 valves offhand, maybe other forum members do. As with all vintage valve equipment, though, there will be several capacitors which need changing, no doubt including the one often referred to as 'that capacitor' which if not changed may result in damage to the output transformer and other components and could well be the cause of the distortion.

The skating may be due to a worn or damaged stylus. As to the mat, they will be almost impossible to source these days.

[nicey1977]

Thanks live wire.

I think I'll just find a ten inch rubber mat and go with that.

Any idea on cartridges to use?

[suebutcher]

If it's got two ECL86 valves, it's not a Mark 1 or a Mark 2. It'd have to be from the sixties. Is it stereo or mono? The ST12 is a BSR stylus, so it's a good bet it's a BSR cartridge. If so, the cartridge number will be on the top side of the cart, hidden by the head.

[nicey1977]

Thanks for the reply.

I've checked the cartridge again but cannot find any numbers or markings.

How would I tell if it is stereo or mono? I believed all black boxes were mono?

Thanks
Gary

[suebutcher]

There were at least a couple of Pye "Stereophonic Black Boxes". Is your player a table model with a curved front and speakers at the sides, or a wide cabinet on four tapered legs? (See examples)

The cartridge, whatever it is, has to be stereo because of the four pins. If it's white plastic, I'd guess it's a BSR C1. If it does need replacing, it's easy to find later BSR carts that will fit. Two ECL86 valves also suggest a stereo player. If you can see two audio output transformers as well as two speakers, then it's certainly stereo.

[Herald1360]

The wide low Black Box was the G63 which had 4 ECL82s (and an ECC83 and EZ81) in the amplifier. Its cartridge was a Sonotone 8T in an AT6 deck.

(My parents' one ended up as a "separates" system some time in the early '70s )

[nicey1977]

It's the table top version, the box so to speak.

The annoying thing is the manual states it is mono and shows that amp and valves but it is completely different to what's under the deck.

You have to excuse my ignorance though as I am 100% novice to this.

[Herald1360]

Two ECL86s in a Black Box is most likely push pull mono.

[suebutcher]

I think we might need some pictures to get anywhere with this. It's possible that the mono Pye amplifier's been replaced with a stereo amp. There was a popular stereo design in the sixties based on a Philips circuit that used two ECL86's. As for the cartridge, you could buy a replacement ST12 stylus and see if the sound improves. You don't have to know the exact cartridge model to do this.

[Tractorfan]

Hi,
I reckon, along with Herald1360, that it's push-pull mono. The ECL86s are effectively two valves in one bottle. Each is a triode-pentode where the two pentodes (the "L" in the type no.) form the push-pull output stage with one of the triodes (the "C") as a phase-splitter. The other triode will be the pre-amp stage.
Cheers, Pete

[nicey1977]

Thanks for all your replies and help so far, i have taken some photos to hopefully shed a little more light on the subject:

http://i208.photobucket.com/albums/b...77/image-6.jpg



http://i208.photobucket.com/albums/b...77/image-5.jpg


http://i208.photobucket.com/albums/b...77/image-4.jpg


http://i208.photobucket.com/albums/b...77/image-3.jpg


http://i208.photobucket.com/albums/b...77/image-1.jpg


http://i208.photobucket.com/albums/b...77/image-2.jpg


I hope they show up here.

[julie_m]

That's clearly a mono amplifier. There is one output transformer, and it is wired to both speakers.

You need to replace the coupling capacitors to the pentode grids (pin 8 of ECL86) pronto. ECL86s really don't like grid current, and Black Box output transformer primaries are notorious for failing open-circuit. For a quick confidence test, unplug the ECL86s and measure the resistance between pin 6 of one valveholder and pin 6 of the other: an open circuit is bad news.

['LIVEWIRE?']

From the photos, nicey 1977, that looks like an amplifier taken from a Hacker GP42 Gondolier,(or it's add-on counterpart, the AL42, and fitted into the Black Box in place of the original amplifier. If, so, the quoted power output, according to 'Radio Servicing' is 7 watts into a 15 ohm speaker. If the 2 speakers in the Black Box(why were they called that?)are wired, as they originally were)in parallel the load impedance will be ca. 4 ohms(I think the BBs speakers were each 8 ohms), then it might be better to rewire them in series.

[radiotircoed]

No help at all but definitely a new on me although it looks original enough. For what it's worth I agree with livewire.. Very Hacker looking..

['LIVEWIRE?']

What 'AJS Derby' says is still relevant, however, so I would replace the grid coupling capacitors to the ECL86s, and also check the resistance as noted in his post, although, AFAIK, Hacker output transformers seldom fail open circuit.