23rd Apr 2019, 8:10 pm | #21 | |
Dekatron
Join Date: Nov 2003
Location: Fakenham, Norfolk, UK.
Posts: 4,257
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Re: Bush TR91
Quote:
I'm not sure the PP10 existed quite in time to have been an option for the RT1, but it was used in a couple of Roberts' later and larger portables, the RT7 and RT8. Paul |
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13th May 2019, 8:58 pm | #22 |
Octode
Join Date: May 2003
Location: Belper Derbyshire
Posts: 1,936
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Re: Bush TR91
I have been following this thread with interest and spotted an unrestored one at the NVCF on Sunday for £5. As the construction looked particularly interesting I picked it up for a restoration even though transistors are not really my thing. Looking forward to restoring this.
Christopher Capener
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Interests in the collection and restoration of Tefifon players and 405 line television |
13th May 2019, 10:26 pm | #23 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
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Re: Bush TR91
I;ve never owned one of those Battery-only Table radios, and in fact it's years since I've even seen one. I wasn't particularly thinking of, or looking for, sets of that type, at the NVCF yesterday, so there could have been some there. Between 1955 & 1966 I lived in an old house with no mains electricity or other modern facilities. At different times we had a HMV Table Radio, can't remember the model no, which ran from a 120v Dry battery and 2v Accumulator, and two different versions of the Ever Ready Sky Queen, which used the B136 90v + 1.5v Dry batery. The Sky Quen's don't really qualify as 'table Radios', as, IIRC, they had handles, plus of course, they used the '96' range of valves. AS has no doubt been pointed out before on this forum, because radios cost at least the equivalent of £300 in today's money, they were looked after, and repaired when they went wrong, and I guess most households only had one radio, too.
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16th Apr 2021, 7:06 pm | #24 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,874
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Re: Bush TR91
Thread re-opened as requested.
Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
17th Apr 2021, 7:01 am | #25 |
Hexode
Join Date: Jun 2012
Location: Chester, Cheshire, UK.
Posts: 421
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Re: Bush TR91
These are a great set and one of my personal favourites. Mine came via eBay (can't remember how much it cost but it wasn't a lot) and all that was needed was a quick squirt of servisol and a new detector diode (the one that lives in the final I.F transformer. It's doing sterling duty as my bedside set although there is a noisy transistor in the amp that I will get around to one day.
I hope you enjoy using it. |
17th Apr 2021, 7:12 am | #26 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Bush TR91
I have the Ferguson 626 BT model which originally used a PP10. The set performs well
on MW/LW but FM sensitivity could be better. Running on a 6 x C cell holder. I also have a National AB-361 which has MW and 2 x SW. It is unusual that it uses Mullard transistors OC45,71,76, and OA70, and 2 x MC102. Not sure of the date. |
17th Apr 2021, 10:09 pm | #27 | |
Heptode
Join Date: Sep 2013
Location: Ellesmere, Shropshire, UK & Co. Cork, Ireland.
Posts: 501
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Re: Bush TR91
Quote:
So I am a pit puzzled as the hiss goes right down if I disconnect the signal path between TR5 and the phase splitter transformer T1. I can't see how TR6 and TR7 are the culprits. I will double check the resistors and caps... In other words the problem seems to be in the region of T4 and T5 but the transistor substitutions made no difference.
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Dom Less snakes...more ladders! Last edited by sexton_mallard; 17th Apr 2021 at 10:32 pm. Reason: Confusion over emitter of TR5 and C31 hiss |
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18th Apr 2021, 6:46 pm | #28 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Bush TR91
Agree on the great styling, forgot to mention. Concentric tuning and volume not often
seen, the only one I have like that is the Ferguson 3146 portable "woodie" set. |
17th May 2021, 10:32 pm | #29 |
Heptode
Join Date: Sep 2013
Location: Ellesmere, Shropshire, UK & Co. Cork, Ireland.
Posts: 501
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Re: Bush TR91
After conceding one of the OC78s was leaky in the output stage to the tune of 10-15mA I went digging through a lucky box of assorted components and found a OC45 and a OC75. I clipped them in with jump leads and hey Presto! Good sound quality with minimum hiss and a total current draw at normal volume back to about 11 to 15 ma. Not exactly a matched pair but my ears says they are!
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Dom Less snakes...more ladders! Last edited by sexton_mallard; 17th May 2021 at 10:41 pm. |