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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 25th Jan 2011, 8:41 pm   #41
Trevor
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Default Re: Tuac Amplifier modules

I have been in contact with Anglia transformers and have spoken in detail to a very pleasant gentleman Nigel
He has given me the following information
2 off units £22.75
10 off units £15.80
50 off units £11,25
This is per item and does not! include carriage or Vat
I know this appears to be rather expensive but when you consider the setting up time etc I feel that it is not unreasonable. However at last I can see why a large manufacturer would be keen to do without them as after 50 off units the cost per unit will not be much lower!
I will have to consider if I will procceed as a stereo amp is going to cost £50 in transformers alone
your comments would be appreciated
regards Trevor
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Old 25th Jan 2011, 8:48 pm   #42
kalee20
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Default Re: Tuac Amplifier modules

That's not a bad price for two transformers - just think, assuming £20 per hour labour rates you've got the equivalent of 2¼ hours work, with materials and design expertise thrown in free!

Doing it yourself you'd never match this in terms of time spent.
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Old 25th Jan 2011, 9:18 pm   #43
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Default Re: Tuac Amplifier modules

Quote:
Originally Posted by Valvepower View Post
From memory the TUAC modules used 2N773 or 2N6254 - I may be wrong though. The 2N773 was used in latter HH amps
Regards
Terry.
2N3773 probably (2N773 is a fleapower device)
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Old 25th Jan 2011, 10:03 pm   #44
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Default Re: Tuac Amplifier modules

Hi,

Well spotted.

Wrong transistor Gromit - Yes it should have been 2N3773.

Did look at the 2N773 data, which is a 65mW 20V 0.1A transistor and would go with a fair old bang in place of a 2N3773

Terry.

Last edited by Brian R Pateman; 26th Jan 2011 at 1:17 pm. Reason: Quote removed.
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Old 25th Jan 2011, 10:10 pm   #45
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Default Re: Tuac Amplifier modules

Hi,

£22 each for a pair of transformers is fair – I’m tempted to get a pair for myself. As a very rough comparison I was quoted £18 today for 1000pcs of a toroidal transformer.

Terry.
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Old 25th Jan 2011, 10:15 pm   #46
Lucien Nunes
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Default Re: Tuac Amplifier modules

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Originally Posted by Valvepower View Post
I’ve just had another look at the module in your amplifier and I feel it may be a Saxon amplifier module
Aha. I have an old disco console that might have the same amps in then. Strangely, I've owned it for years but never actually looked inside it. I will drag both that and the Baker out at the weekend.

Lucien
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Old 26th Jan 2011, 2:12 pm   #47
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Default Re: Tuac Amplifier modules

Quote:
Originally Posted by Trevor View Post
I have been in contact with Anglia transformers and have spoken in detail to a very pleasant gentleman Nigel
I'd be intersted to know what his reaction was, being asked about a transfromer that, presumably, there has been no demand for for over 30 years.

Cheers

Aub
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Old 26th Jan 2011, 7:50 pm   #48
Trevor
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Default Re: Tuac Amplifier modules

Well I think he was a bit suprised and explained that he would have to dig out the design records hence the 24 hour delay in getting a price!
By the way the delivery time from order to delivery is 5-6 weeks
I offered to pay via visa but was told that this was not possible and it would have to be pro-forma invoice
I know that he was suprised as when I asked for 50 off units he asked if i was going into production
The transformer would be very close to the origional but not exactly the same re terminals etc
regards Trevor
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Old 26th Jan 2011, 10:44 pm   #49
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Default Re: Tuac Amplifier modules

Well its a fascinating project. Please keep us informed of the progress. I know these units sounded good to my younger ears all those years ago.

Thanks

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Old 27th Jan 2011, 7:10 pm   #50
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Default Re: Tuac Amplifier modules

I have asked a moderator and i am advised that it would not be a problem to arrange a join buy!
I am willing to pay up front and pass on at cost + vat a carriage any driver transformer for the Tuac
I will give it 4 weeks from today for anyone who is interested in purchasing transformers
before i put in my order if i can get the quantity up i can get the price down all i ask is keep your word
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Old 28th Jan 2011, 9:31 pm   #51
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Default Re: Tuac Amplifier modules

Hi,

I’ve measured the turns ratio of the TP125 driver transformer and attached the results. It appears to have a turns ratio of N2/N1 0.247/1 The DC resistance of the primary is 81.4Ω and the DC resistance of both secondarys are 2.3Ω

This will give a current gain of 4.

I did a couple of quick frequency response sweeps with 100K and 5K secondary loads and they appear to be ok.

The transformer design has to allow for DC flowing in the primary (2N3055 Ic), this may account for its size along with having to deliver the base currents as well.

One of the advantages of the Rogers Ravensbourne diver is the push-pull driver T8 & 9 this means the DC currents cancel so the DC polarization of the transformer will be minimal.

Terry.
Attached Files
File Type: pdf TUAC_TP125_Tx_Tst_5K.pdf (7.8 KB, 449 views)
File Type: pdf TUAC_TP125_Tx_Tst_600R.pdf (7.8 KB, 342 views)
File Type: pdf TP125_Drv_Tx.pdf (14.9 KB, 319 views)
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Old 29th Jan 2011, 8:17 pm   #52
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Default Re: Tuac Amplifier modules

Thanks valve power a good piece of work this confirms what I have been thinking for a no of years now!
you can with a transformer trade voltage swing to current gain something you can not do with any other technology
many many thanks
regards Trev
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Old 30th Jan 2011, 3:44 pm   #53
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Default Re: Tuac Amplifier modules

Got some photo's will look for some others.

Mike.
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Old 30th Jan 2011, 4:28 pm   #54
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Default Re: Tuac Amplifier modules

Hi Mike,

Great Photos.

Now that’s what I call a real disco unit.

I can remember the pair my friend was running back in ’75 was loud, but 4 of them, that must have been real loud!

My friend used to run a small speaker cabinet factory in Southend in the mid 70’s. At the time he also ran a mobile disco, which used a D.J Electronics mixer running a pair of TUAC TP125’s. The speakers were either Electro Voice or Gauss 15” or similar speakers in a folded horn cabinet with a pair of compression drivers for MF and HF. They were not dissimilar to the Orange folded horn cabinets as used by the BBC Radio One road show in the 70’s.

This link may be of interest:

http://www.karillon.com/djelectronics.html

I did know the D.J Electronics guys back in the 70’s - great days.

Terry.

Last edited by Valvepower; 30th Jan 2011 at 4:32 pm. Reason: Tidy-Up
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Old 30th Jan 2011, 9:42 pm   #55
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Default Re: Tuac Amplifier modules

Hi,

I’ve just found and attached another article on transformer drivers from a 1961 copy of Wireless World.

I’ve attached a couple of pictures of a Saxon amplifier advert from PW.

Terry.
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ID:	45911   Click image for larger version

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ID:	45912  
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File Type: pdf WW61_P242_5.pdf (366.9 KB, 367 views)
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Old 30th Jan 2011, 9:54 pm   #56
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Default Re: Tuac Amplifier modules

Thanks Terry - that's got my bedtime reading sorted for tonight.

Looks like a decent circuit - 'concertina' phase splitter, driving push-pull driver transistors, themselves driving (via the transformer) the output pair. Provision for DC balancing the driver transistors, which makes the transformer design an easy job.

Not sure about DC balancing the output series-connected pair as it looks dependent on the bias adjustment - a bit dodgy with no DC feedback loop - but hey it is early 1960's!

A good read coming up...
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Old 30th Jan 2011, 10:59 pm   #57
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Default Re: Tuac Amplifier modules

In this Delco amplifier from 1964 there's provision for balancing the output pair.
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Old 31st Jan 2011, 9:43 am   #58
Trevor
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Default Re: Tuac Amplifier modules

Valve power what a cracking article re the 1961 amplifier Shows that there is nothing new under the Sun!
I bet it was expensive thoughI have done something similar re the phase splitter driver in the past with good results
Re the delco amplifier this is so nearly what I intend to use my Tuac transformers for
I intend a class ab/b noutput stage transformer driven from a class A predriver of about 200 watts per channel into 8 ohms
regards for now Trev
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Old 31st Jan 2011, 1:58 pm   #59
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Default Re: Tuac Amplifier modules

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... 'concertina' phase splitter ...
Before anyone corrects me, on looking more carefully, no it isn't - the first transistor is a common-emitter amplifier with single output. The driver transistors act as phase splitter with the large common emitter resistor.

Unusual to see OC44 transistors in this sort of circuit - especially as AF drivers!

Unusual also to see that the heder photograph is Crown Copyright. Wonder what commissioned the design? I do rather like it!

The comparison with the Tuac amplifier is interesting - the Tuac has a single-ended driver with DC through the drive transformer primary. But I can't help thinking it might be more robust, as it has a much meatier driver transistor than puny OC44's.
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Old 31st Jan 2011, 10:26 pm   #60
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Default Re: Tuac Amplifier modules

Hi,

I have to agree the circuit is interesting with a nice elegance to it. As pointed out the OC44 transformer drivers look rather vulnerable though.

Leak used the OC44 in the first stage of the Stereo 30 power amplifier.

The THD is quoted as 0.031% which in not bad for a 1961 transistor amplifier.

It would be interesting to build it with newer silicon transistors, but this will necessitate the construction of a transformer though, but saying that the construction details are extensive enough though.

Terry.
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