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Old 26th Jun 2017, 5:40 pm   #1
Adam Masters
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Default Dynatron Volume Balance Issues help!

Hi all

I'm new to the boards and new to old turntables. Guitars and my forte record players are my love LOL.

I recently got this lovely old Dynatron and speakers. I've opened it up and given it a good clean and spray etc and there is one small but annoying problem I can't fix.

The balance pot is a bit crackly but nothing too major after a bit of Servisol, but when I plug the speakers in only through the top socket do speakers sound right. Through the top input the speakers I have tried sound great but through the bottom there's loads of hiss and distortion and the speaker is a lot quieter.

Any clues or advice would be greatly appreciated!!

Cheers, Adam.
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Old 26th Jun 2017, 6:16 pm   #2
camtechman
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Default Re: Dynatron Volume Balance Issues help!

The test you did by plugging them in the top socket seems to prove both speakers are ok.

However the problem could be with either the cartridge or a fault in the amplifier.

Could you provide the model number of the deck and, if possible, a picture of the cartridge.

You should be able to remove the head shell (in which the cartridge is fitted) by turning the retaining ring behind the head shell.
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Old 27th Jun 2017, 10:44 am   #3
david freeman
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Default Re: Dynatron Volume Balance Issues help!

Could it be that the other speaker sockets are for a pseudo surround sound effect which use out of phase signals to give a spacious sound using 4 speakers? If this is the case, you will only get these out of phase signals through speakers connected to those sockets, which will sound very much as you've described.
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Old 27th Jun 2017, 11:03 am   #4
toshiba tony
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Default Re: Dynatron Volume Balance Issues help!

I can't quite make it out but I think that was called the Mazurka". I think it may have been before the Hafler system was ever used. I'll go through my used guides for such gear.
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Old 27th Jun 2017, 11:14 am   #5
ms660
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Default Re: Dynatron Volume Balance Issues help!

Could it be just 2 speaker sockets and both speakers when tried work ok in one of them but not in the other?

Lawrence.
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Old 27th Jun 2017, 11:32 am   #6
Nickthedentist
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Default Re: Dynatron Volume Balance Issues help!

If this is the HFC10 Mazurka, then the R&TVS book data is on the DVD or available as a download from Paul Stenning for £1.99:
http://www.service-data.com/product....16/1825/a11316

This implies it's only got two LS sockets, one for each channel. So essentially, one of the channels is misbehaving.

The unit also has two 5-pin DIN sockets for connecting a tape machine or radio tuner. A buzz test via these would be a good move to see if the amp really is faulty on one side.

Nick.
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Old 28th Jun 2017, 1:02 pm   #7
jamesperrett
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Default Re: Dynatron Volume Balance Issues help!

That's definitely a Mazurka - I had one for a while. The deck was a Garrard SP25Mk2 and I seem to remember it was fitted with a Goldring G800 (or maybe a G850) cartridge. Dirty pots and switches were a problem on mine.

It might be worth connecting the tape outputs to another amp to see if they are noisy. It would also be worth trying some of the other inputs just to check whether the noise is coming from the cartridge/preamp or a later stage.
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Old 30th Jun 2017, 3:15 pm   #8
Adam Masters
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Default

Hi Guys.

Thanks for your responses! I've carried on playing around and tried all suggestions ie testing different speakers and testing them independently in each socket. Its definitely that bottom socket I think. I've whipped the cartridge out and it seems sound as a pound! Attached pics. Given it a spray of Servisol just in case too!

I have actually got a copy of the manual off Paul so swotting up on it. Ill try testing the tape out for noise too and report back.

Driving me up the wall as I just got a set of old Sony 3 ways in a similar colour and they sound great! Or at least through one side.

Also just tried a buzz test through the tape and radio channels and they are both fine and emit equal sound.

Cheers, Adam.
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Old 30th Jun 2017, 4:41 pm   #9
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Default Re: Dynatron Volume Balance Issues help!

Have you tried cleaning the selector switches SW1A and SW1B?

Try swopping over the red and white leads on the rear of the cartridge, so that the L channel is played through the R speaker and vice versa.

There's a BC109 transistor in each channel which is used as a pre-amp when switched to GRAM. The rest of the circuit is common to GRAM, RADIO and TAPE.
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Old 2nd Jul 2017, 10:27 pm   #10
camtechman
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Default Re: Dynatron Volume Balance Issues help!

Adam Masters

Quote:
I've whipped the cartridge out and it seems sound as a pound! Attached pics. Given it a spray of Servisol just in case too!
Did you really spray the cartridge ?!
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