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-   -   Xindak attenuation for use with Leak Stereo 20, help please (http://www.diyaudio.com/forums/tubes-valves/101812-xindak-attenuation-use-leak-stereo-20-help-please.html)

camperman 12th May 2007 09:00 PM

xindak attenuation for using with leak stereo 20 help please
 
ive recently been given a xindak xa3200 mk11 and was wanting to use it with my leak stereo 20 but i can hardly get the volume on without it being very loud is it possible to attenate the lead from the pre to power without altering the sound quality and if so any advice would be great ie resistor values .ps i tried a 20 k pot but it seemed to alter the sound cheers again :xeye:

Eli Duttman 13th May 2007 02:19 AM

What is a xindak xa3200 mk11? If it's a CDP, build attenuation into the RCA plugs at the Leak's I/P jacks. Use 1/8 W. 1% metal film parts. It's the good old resistive voltage divider technique. 6.8 KOhm and 3.4 KOhm parts will give you 9.5 dB. of attenuation. That should provide some relief from the "hair trigger" volume control you're experiencing.

camperman 13th May 2007 04:38 PM

hi cheers and a xindak is a chinese valve line level pre amp, is that figure you quoted enough as i put a 20 k pot inline and it only worked at nearly full on sorry to be thick but never done any attenuating before cheers again :D

Eli Duttman 13th May 2007 07:05 PM

OK, the xindak is a line stage, not a CDP. That makes things more difficult.

The problem is too much gain, end to end. You can try a guitar amp trick. Please notice in the Leak schematic that the 2 sections of a 12AX7 are shared between both channels at the I/Ps of the amp. The amplification factor (mu) of a 'X7 section is 100. Other than a mu of 40, the characteristics of the 12AY7 are very similar to the characteristics of the 12AX7. Pull V1 and insert a 12AY7 in the socket. Use an inexpensive tube initially to get a feel for the effect on system volume and tone. If the effect is to your liking, buy a nice BVA made CV2650.

BTW, inserting a 20 KOhm pot. in the "hot" line is improper technique. The "ends" of a 50 or 100 KOhm pot. are connected across the "hot" and "cold" wires. The wiper gets connected to the "hot" center pin of the RCA plug. "Cold" is common everywhere. The inline attenuators should be placed very close to the power amp I/P jacks. The fixed resistance value ratio I previously provided will work, if you scale the values up to make the total resistance come in at approx. 100 KOhms.

EC8010 14th May 2007 06:37 AM

Camperman, you have far too much gain. A CD player produces 2V, but the Leak only needs 120mV and you have added a pre-amplifier to make it even more sensitive. A 100k resistor in series with the input of the Leak, plus a 4k7 down to ground will solve the problem.

PS. Please use the "shift" key when posting on the forum. Posts without correct capitalization look poor and deter others from helping you. Thank you.

camperman 15th May 2007 11:27 AM

Thanks for the advice ,I tried the other valve but it didnt lower the level enough .Ill try the resistors next , thanks again great help for an electronic newbe cheers :D

camperman 15th May 2007 04:15 PM

Right then, ive tried the resistors, its getting there but its still not enough, needs more attenuation please could you give me some other resistor values to increase the level of attenuation. Thanks a lot cheers again CAMPERMAN:D :clown:

EC8010 15th May 2007 06:22 PM

Crumbs, not enough? Try 2k2 in lieu of the 4k7, and if that doesn't work, 1k.

camperman 15th May 2007 06:59 PM

Sorry to be thick AGAIN, but when you said 4k7 i presumed you ment 47k . I take it im wrong and if so what does 4k7 mean is it 4.7 k ,i must look into this electronics stuff and read up on the link on here sorry again for my ignorance cheers :cannotbe:

SY 15th May 2007 07:15 PM

4.7k


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