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Old 20th April 2011, 08:40 AM   #121
UV101 is offline UV101  England
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You could try these
http://cgi.ebay.co.uk/To99-DIP8-Dual...#ht_2580wt_783

If you want to test singles in pairs vs dual?? Search eBay for opamp pcb
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When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
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Old 9th June 2011, 11:56 AM   #122
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cheers!

just noticed one very sexy Radiant on German ebay. One button on the front panel is what I was always dreaming about, nothing extra

here is the link
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Old 9th July 2011, 11:38 PM   #123
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Quote:
Originally Posted by UV101 View Post
I would also consider the audiogd OPA discrete opamps (I think the sun is supposed to be very similar to Burson!)
I can vouch for Audio GD's
Have Earth and Sun models and they are superior to 627's and 49710's ( I have used these too ) in the context of my system.

Don't want to compare or make statements in relation to Burson or the similarities therein ( hahaha ) but I can have an e mail from Kingwa of Audio GD within 6 hours answering my sometimes stupid questions - he's some guy.

What really baffles me is why people pay so much for Bursons...?
Doesn't anyone visit the Audio GD website ?
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Old 11th October 2011, 08:47 PM   #124
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must admin that Bursons are highly overpriced, though there are many reviews in the net saying how good they are. Perhaps this is one of the reasons why people are ready to pay 10x more just for the name

AndrewGM

where did you use Earth and Sun opams, was it preamp or cd or some other devise?
Asking as I have finally changed old stock opams in Restek's preamp stage to 3x 49710 and noticed the difference immediately (plenty of other mods have been done accordingly too) and as it's the weakest (simplest) point the amp, probably swapping to discrete components like Bursond or Sun/Earth opams could bring even bigger results hence asking
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Old 25th January 2012, 12:21 PM   #125
UV101 is offline UV101  England
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Hoping you're still watching this thread dtses!

Did you ever check your biasing?

Looking at mine, each output device is running into 0.15r and only passing 1.5mV.
This means the bias is set at approximately 10mV per device. According to the information I've got (Thanks "Thomo", "Fidelity Audio" and the TNT web Pages) this is woefully low. TNT suggest at least 100mA min and 150mA max per device (assuming the heatsinks etc are up to the job). Obviously this is biased more into class A and so the amp will run much hotter and draw more current even at low volume.

Based on this, I've started to increment the bias.

This table is based on 0.15r
1.5mV = 10mA
4 mV = 26.7mA
8 mV = 53.3mA
10mV = 66.7mA
15mV = 100mA

I've set mine to approx 10mV so 66.7mA and wil run it for a few hours to see how it behaves but the initial indication is that it is very dynamic (not that it wasnt before) and eager. We'll see where it goes.

Any subjective opinions on my as usual "cavelier" approach welcome!

The TNT article on biasing is here
Adjusting the Bias Of Your Amp [English]
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When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
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Old 25th January 2012, 08:16 PM   #126
UV101 is offline UV101  England
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OK so after a few hours serious listening and I've backed it off a bit down to 7.5mV which should be about 50mA. Running at high volume for an extended period, it got much hotter than I was comfortable with. Although the heatsinks are large, I think they could do with being much larger!!

Listening impressions.....Wow!!!! much more dynamic at lower volumes and an icredible amount of detail in the sound. Placement was extraordinary! I've never heard my system sound like that before!! Awesome attack and just more of everything.

Leaves me with a question.....why was it set so low from the factory??? Is it just to be on the safe side?? seems way off the mark to me...unless I'm missing something??
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When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
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Old 26th January 2012, 01:04 PM   #127
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that seems to be nice and simple improvement, Ian

I have replaced old oxidated wires between ALPS pot, pre and power sections with OFC shielded Tasker C114 0.25mm cable. Looks sexy, hope that some audible improvements also appear.

Will try that biasing mod a bit later for sure.
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Old 26th January 2012, 10:20 PM   #128
UV101 is offline UV101  England
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I really should sort the internal wiring out in mine!!

I did do this kind of pointless mod tonight.....was a right pain in the @rse!!! But I got this thing about blue lights (unless they are following me!!)

Click the image to open in full size.
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When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
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Old 16th March 2012, 06:28 PM   #129
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cheers!

left channel produce very distorted sound on the preamp output (check by desoldering new replaced wire between pre and power section). What could be the cause?

I didn't turn on the amp for several months after I swapped to Tasker wires. Second opamp (previously was 2 LME49710HA) replaced to OPA2132. No mods since that.
Checked all opams in pre section by replacing with working OPA2132s. All opams are fed with according +- voltage.

What could be the cause? What else could I check?
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Old 18th March 2012, 09:37 AM   #130
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thanks!
solved by resoldering 1st opams buffer.
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