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Old 3rd March 2010, 01:22 PM   #991
Salas is offline Salas  Greece
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Quote:
Originally Posted by Peppe View Post
Hi all,

may I ask 2 basic questions?

1) Do I have just parallell the inputs RCAs for a tape-loop output?

2) Nobody has already tested Sowter 3575 trafo for bal ins and outs?

Thanks
1. Yes. It would be better to parallel the output, since you would buffer your source that way, but that would be affected by volume control. Depends if you wanna listen normally when you record and tweak volume along.

2. I haven't heard of anybody having done that yet.
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Old 3rd March 2010, 06:00 PM   #992
Peppe is offline Peppe  Italy
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Thank you Salas.

My idea is to use an input-loop to feed my headphone amp and let the B1 drive the active desktop speaker.

Untill I will have boards etc. I will think if going or not with balancing trafo.
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Old 3rd March 2010, 06:11 PM   #993
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By the way, has anybody yet tried the buffer with headphones? I will try it as soon as I have it inside a case.

Salas, could be any problem with, maybe impedances? I'm planning to test it with a pair of senns HD595, 50 Ohms.
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Old 5th March 2010, 12:15 AM   #994
Salas is offline Salas  Greece
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B1 does not have the idle current nor the low Zo for that I am afraid.
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Old 5th March 2010, 04:18 AM   #995
sugden is offline sugden  Singapore
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I have finally complete all the components soldering for DCB1. Now still waiting for Alps 20k volume pot from RS components, and source for chassis for it.
1. Main supply rail: +10.64V and -9.67V
2. Volt. drop across 68//68 : 1.613V and 1.750V
3. DC offset: R= 1mA and L= -2mA
May i know i there anything wrong with my DCB1?

Thanks.
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Old 5th March 2010, 04:53 AM   #996
Salas is offline Salas  Greece
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Congrats. Its a fine young & healthy DCB1 with nice lights and green filter caps. Tell us how you will like it after you listen.
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Old 5th March 2010, 08:47 AM   #997
AndrewT is offline AndrewT  Scotland
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Hi,
the 68//68 with just 1.6V across it is passing just 47mA through the CCS.
The two B1 stages may be taking Iq~8+8mA, the shunt circuit could be taking 12mA. That leaves just 19mA passing through the shunt FET.
That may be a bit low.
Experiment with adding a further 68r to make three in parallel and maybe a fourth 68r in parallel. Each 68r passes ~24mA through the CCS.
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Old 5th March 2010, 09:09 AM   #998
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Mine definitely sounded better with about 10R in the place of the 68//68

Fran
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Old 5th March 2010, 09:34 AM   #999
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by woodturner-fran View Post
...sounded better with about 10R in the place of the 68//68
and the rest of the information we need for this to help us decide?
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Old 5th March 2010, 11:19 AM   #1000
sugden is offline sugden  Singapore
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Will try adding more 68R in parallel to it, once I received Alps 20k volume pot from RS. Will report back back the out come. Right now can I test DCB1 without the volume pot? connect to my system Cambridge audio C840 CDP and Mcintosh MC240 power-amp driving JBL 4310. Because Mcintosh MC240 input come with volume control.
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