Musical Fidelity X10-D - changing tubes problem

[gsrai]

Hi everyone

As you can see I am new to this forum but could really do with some advice (sorry if this is in the wrong section).

I have just bought an X10-D tube buffer (round one) so I can play with the tubes and I have also bought some Jan Phillips 6822's.

I've opened up the tube and when I pull the board out the back it stops half way because the LED is wired in at the front. I've tried pushing the LED but not too hard so it pops out but it wont.

Could someone tell me what I'm doing wrong and secondly, if ther LED breaks is there a specific model I should replace it with (I want to change it to blue anyway).

All help gratefully received

 

[Shoog]

It is a bit of a design issue with the LED. If you can use a soldering iron I would suggest splicing in a little bit of extra cable. Simply cut the cables (making certain to note which lead is which) and solder in an extra 6inchs- or even better use the opportunity to change to a blue one. If you do this the Blue LED may burn a little dimmer than the red it is replacing. Even if you don't have soldering iron experience you could use electricians joining blocks. If you don't do this then tube rolling will become a real pain.

I would caution against the benefits of tube rolling with this particular valve buffer. It is run at such low voltages that I suspect that the tube used as stock is specifically chosen for it sound qualities in this unit. Changing to another tube might not produce happy results. In the one I used to have I tried Mullard ECC88's and found the result much to soft for my taste.

I think a more useful improvement could be had by beefing up the 12VAC power pack.

Shoog

 

[gsrai]

Thanks for that, I just cant seem to push the Led out so cant figure out how to change it to a blue one (do you know how to decide on which model of LED to use) - as you can see I am a complete novice to this and dont want to mess things up but am very intrigued!

 

[kepa1]

Hello,

Normally you could do without desoldering the LED, just unscrew all 6 screws from the black panel and gently pull the silver panel. That's it!

Shoog is right about the issue of changing valves, not that it is dangerous, but the X-10D alrady have 6922s.

Bye

 

[gsrai]

Hello,

Normally you could do without desoldering the LED, just unscrew all 6 screws from the black panel and gently pull the silver panel. That's it!

Shoog is right about the issue of changing valves, not that it is dangerous, but the X-10D alrady have 6922s.

Bye

Kepa1
Thanks for the note, I thought the X10-D had ECC88 and they were poor quality hence why I bought some jan philips - have I wasted my money?

 

[Shoog]

Any LED should do the trick. It may be dimmer because different coloured LEDS have different voltage drops and the circuit is set for a particular voltage drop - shouldn't be a big issue, if at all.

The 6922's in the X10D are surprisingly good sounding. I have used them in different situations and they haven't been noticably worse sounding - maybe a bit bass shy. When running a valve at such low voltages and probably currents their particular sound will come out more, if this is slightly less than neutral then the sound will be less neutral than running the same valve at higher voltages.

A 1A 12VAC power supply will help to bring up the bass of the X10D.

Shoog

 

[arnoldc]

here's a DIY X-PSU

http://www.rock-grotto.co.uk/easyxpsu.htm

 

[andrew_whitham]

just spotted this

Thanks for the note, I thought the X10-D had ECC88 and they were poor quality hence why I bought some jan philips - have I wasted my money?

Just to bring this back from the dead, If you have "surplus" 6922's, see if you can get the heater voltages to match. Since each channel is in one envelope they dont always even out - Had just 5v on one in mine.

Careful though when measuring these might only have 12vAC input but theres 60vDC across the tubes

Andy

 

[adason]

here is nice link for you gsrai
http://www.rock-grotto.co.uk/x-ccessories.html

 

[theadmans]

I have just bought an x10d and although I am pretty happy with the upgrade in sound in provides with it's original Philips 6922 tubes I am tempted to buy some ECC85s to try in it from Ebay.

As a complete novice when it comes to tubes I would like to know what the following description on Ebay really means:-

"Tubes are in perfect physical Condition, The tubes were examined with the tube tester of neuberger RPM 375 (one of the best tube tester) with the following results:

a) 13/15 mA
b) 13/11
(10mA=100%)"

I have seen tubes advertised as "matched" pairs - if I buy the above tubes are they likely to be suitable for my x10d.

Also is it really that difficult to swop the tubes in the x10d (comments above suggest having to lengthen the LED lead) ? I have a single Philips screw on the back panel as well as a couple of Hex screws. On the front panel there are a couple of hex screws. Do you need to remove both the back and front panels to swop the tubes?

 

[Shoog]

I don't think a ECC85 will be a drop in replacement. The ECC88 is what you want.
The tubes can be replaced with only the front panel off, though it is tight and fidley.
Don't think of a tube upgrade as the first upgrade option. You will get much better results by replacing the power supply with something more beefy. A 50VA toroidal would give good results. There is a web site somewhere which describes what to do.

Shoog

 

[theadmans]

I don't think a ECC85 will be a drop in replacement. The ECC88 is what you want.
The tubes can be replaced with only the front panel off, though it is tight and fidley.
Don't think of a tube upgrade as the first upgrade option. You will get much better results by replacing the power supply with something more beefy. A 50VA toroidal would give good results. There is a web site somewhere which describes what to do.

Shoog

Thanks for your reply Shoog - the only reason I was thinking ECC85 was that I have read on the internet of a number of people using them successfully with the x10d. By the way can you cast any light on whether I need a "matched" pair of valves?

So am I right in thinking from your reply that you don't need to remove the back panel of the x10d - only the front? Then presumably you pull the circuit board out of the front of the x10d?

Is the power supply you refer to this one (I might have a go at this if I can get the parts):-

http://www.rock-grotto.co.uk/easyxpsu.htm

 

[Shoog]

I personally wouldn't waist my money on a matched pair. ECC88's are fairly consistent. Matching only really becomes an issue in push pull output stages. Anyway the match will slip in a relatively short time. Really its a way of fleecing money out of HIFI freaks.

When I tried some tube rolling with my X10D I think I only needed to remove the front panel (or was it the back), to be honest its no biggey to take off the panel and see. Come to think of it, it must be the back panel, because the power socket at least is mounted onto the circuit board. Its well worth extending the LED leads to make adjustment easier in future.
I have to warn you that I was less than happy with the result of trying some NOS Mullard ECC88's, very syrupy. I went back to the stock ones in the end. This circuit uses the valves on the edge of their voltage range and I have a gut feeling that the circuit is tuned to get the best out of the stock Valves, and everything else is likely to spoil that tuning.

Is the power supply you refer to this one (I might have a go at this if I can get the parts):-

http://www.rock-grotto.co.uk/easyxpsu.htm

Thats exactly the site I was refering to. Pound for pound thats the biggest improvement you will get from the X10D, parts are easy to get from Maplin or Farnell.

Shoog

 

[fdegrove]

Thanks for your reply Shoog - the only reason I was thinking ECC85 was that I have read on the internet of a number of people using them successfully with the x10d. By the way can you cast any light on whether I need a "matched" pair of valves?

So am I right in thinking from your reply that you don't need to remove the back panel of the x10d - only the front? Then presumably you pull the circuit board out of the front of the x10d?

Is the power supply you refer to this one (I might have a go at this if I can get the parts):-

http://www.rock-grotto.co.uk/easyxpsu.htm

Hi,

Actually the ECC85 should "work" in this particular instance but somehow I suspect that people prefer it just because it goes a tad louder not necessarily better....

NOS European 6922 does sound a bit bass shy and anemic compared to the Sovtek 6922 this is because the cathodes of the European professional miniature valves are treated to make them more reliable. At least some NOS E88CCs are, depending on vintage. Unless you can decipher the acid etched manufacturing codes there's no sure way to tell.

ECC85 OTOH were common as mud in the old portable radio days and are quite sweet sounding. Too sweet and forgiving to my taste more often than not.....

Note also that the ECC88 family sports an internal shield which is to grounded if both channels share a common envelope for best channel separation. Not saying this is the case with this particular design though.

Hope this helps,

 

[Shoog]

NOS European 6922 does sound a bit bass shy and anemic compared to the Sovtek 6922 this is because the cathodes of the European professional miniature valves are treated to make them more reliable.

This would seem to support my findings with the Mullards.

Shoog

 

[Gost22]

tube buffer x10-D with 6n23p-EV

Hi all!
If you replace this 6DJ8 in bafferu with Russian tube 6n23p-EV ate some changes are needed in the schemayics?
Here is the seed buffer X10-D
Thanks for your help!

 

[cobra]

Russian tube 6n23p-EV

no change req.. just plug and play

 

[Gost22]

no change req.. just plug and play

The sound it gives the tube 6n23p, if you have experience?
thank you!