Heifetz Posted May 17, 2017 Share Posted May 17, 2017 i, This is my amp (pic below). But I don't know if its an ClassA or Class AB. How do I tell if its one or the other? Its a TSLIM Diva BlueSky. Its impossible to get a response from Singapore and haven't received on from Audio Salon. Your help would much appreciated. Thx so much, Bob Link to comment Share on other sites More sharing options...
Martykt Posted May 17, 2017 Share Posted May 17, 2017 (edited) Class AB push pull. Most common configuration for quad el34 or kt88 etc amps. I found this link which has a bit of info on it. http://ls35a.proboards.com/thread/9/diva-blue-sky-amp Edited May 17, 2017 by Martykt Link to comment Share on other sites More sharing options...
Heifetz Posted May 17, 2017 Author Share Posted May 17, 2017 Thx Martin, I hope you are well. I've been googling so much and never found that page before. How d'you do that so quickly Thx so much, Bob Link to comment Share on other sites More sharing options...
Sir Triode Posted May 17, 2017 Share Posted May 17, 2017 (edited) The designer Tze Sian Lim is on Facebook and Linkediin. What is the issue with the amp? Edited May 17, 2017 by Sir Triode Link to comment Share on other sites More sharing options...
VanArn Posted May 17, 2017 Share Posted May 17, 2017 EL34 valves run in class AB ultra linear PP (fixed bias) give typically a maximum O/P power of 30 watts. Run as pentodes, with a view to having a reasonable lifetime, i.e. not as a guitar amplifier ,you can achieve around 50 watts. Examination of the amplifier via testing it and a check of the circuit would be required to give an exact rating. Otherwise a review from a respected audio magazine would help in establishing the facts about the product. 1 Link to comment Share on other sites More sharing options...
Martykt Posted May 17, 2017 Share Posted May 17, 2017 20 minutes ago, Heifetz said: Thx Martin, I hope you are well. I've been googling so much and never found that page before. How d'you do that so quickly Thx so much, Bob Pure luck Bob !! Link to comment Share on other sites More sharing options...
Heifetz Posted May 17, 2017 Author Share Posted May 17, 2017 (edited) @VanArn @Sir Triode Thank you. I would like to bias the amp. Its not been done for about two years and it concerns me a little. I'm looking at buying a bias meter such compu-bias meter http://www.compu-bias.com as I thought it a little safer than the multi-meter. I saw an Aussie product 'Evatco bias meter' but don't think its available anymore. May be another is better - I'm not sure yet. So I'm just gathering information. Bob Edited May 17, 2017 by Heifetz Link to comment Share on other sites More sharing options...
Sir Triode Posted May 17, 2017 Share Posted May 17, 2017 Bob, You can email TS Lim at tzesian.sg@gmail.com Link to comment Share on other sites More sharing options...
Martykt Posted May 17, 2017 Share Posted May 17, 2017 9 minutes ago, Heifetz said: @VanArn @Sir Triode Thank you. I would like to bias the amp. Its not been done for about two years and it concerns me a little. I'm looking at buying a bias meter such compu-bias meter http://www.compu-bias.com as I thought it a little safer than the multi-meter. I saw an Aussie product 'Evatco bias meter' but don't think its available anymore. May be another is better - I'm not sure yet. So I'm just gathering information. Bob Just remember the bias adjustment pots are inside the amp anyway so a bit of electrical safety will have to adhered to regardless. The bias meters in one way may actually be more awkward as they require swapping the tubes out to fit the adapter. Link to comment Share on other sites More sharing options...
VanArn Posted May 18, 2017 Share Posted May 18, 2017 The compu-bias gadget would be a handy item if it was not limited to a one at a time set-up which requires pulling out a valve and going through a cool down and heat up process. it would be fine for a S.E. amplifiers, as long as you have a multiple of socket adaptors to suit the various valve bases. Setting the bias of push-pull amps in particular requires multiple adjustments over a period of time to make sure the adjustment is stable. Some manufacturers fit sockets or test points to make it a simple task. I would stick to using a good quality digital multimeter for this purpose and the ability to make other measurements. Link to comment Share on other sites More sharing options...
trobbins Posted May 18, 2017 Share Posted May 18, 2017 Bob, are you not posting technical information that you have available, as you are talking about biasing the amp, and that would seem a bit premature without any details apart from the valve model ? Link to comment Share on other sites More sharing options...
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