Ideas for a MF X10-D style line-buffer clone CHEAP????

[DSJR]

My penny-pinching quest continues....

I put the Croft preamp back into service this week and once again it's working its magic up to a point...

I use three amps with a 25K input impedance with the Croft, two in bridged-mono form for the speakers driven from the preamp outputs. The third is used as a headphone amp and this is a problem when driven from the record-outs on the Croft, which use one resistor in series to "load" the output...

The problem is this, the phono stage in the Croft seems to have a high ouput impedance (the reason why my preamp has 500K pots fitted) and if all three amps are connected, the bass all but disappears on the phono input - something I've commented on before. remove the "headphone" amp from the tape outs and all the bass comes back on vinyl and the Croft "magic" is restored in abundance. The line sources are simply routed straight through to the record outs with no buffering other than the resistor in series.

Musical Fidelity X10-D units now sell for their brand new price of £120 nigh on12 years ago and the V3 tends to go for nearly £200 as it's been discontinued. Is there anything else out there cheaper, or do any of you have such a thing, home made or not, that you'd sell for less than a ton?

The idea of this buffer is that its input impedance is around half a meg (500K) and the output impedance low enough for a 10K - 25K amp load. If I asked anyone to custom-make one, I suspect the price would be through the roof and I just can't do this at the moment.

Cab anyone help? I've asked an Ebay seller who tried to sell an X10D (it dodn't reach reserve) if he's going to re-list it, but haven't yet had a reply..

[edit] P.S. Glenn has kindly offered to modify the phono stage output to enable more available pots to be used and this may all but cure the problem, although I'd still like an active (valve/FET?) style buffer in circuit if possible.

[Ali Tait]

You could try one of these-

http://cgi.ebay.co.uk/Analog-King-Tu...#ht_6204wt_960

No idea if they're any good.

[DSJR]

I looked at that, but what worried me is the output impedance is quoted as 5K, which is ten times worse than most modern source components. maybe it doesn't matter, I don't know - the amp input is 25K best case (it has gain controls for volume).. The X10 models have less than 50 Ohms output impedance...

It's so cheap, it's almost worth an experiment.........

[Mike]

Nelson Pass B1 Buffer...

http://www.passdiy.com/pdf/B1%20Buffer%20Preamp.pdf

http://www.enjoythemusic.com/Magazin...eamplifier.htm

[Clive]

There are various clone circuit boards that used to be available from HK, probably they are still around.

I have sitting here an X10D that I've not used for several years. The wallwart needs a new plug (the end that goes into the X10D), I expect I have something suitable lying around. The wire from the wall wart is a little short (4ft) and the case has some slight marks.

The X10D is the original version as far as I recall. You're welcome to try it and if you want, I won't ask for a silly ebay price.

Clive

[DSJR]

That would be great please. It'll be sat within inches of the mains plugs and of the price is right, I'll save for the XPS or ask for more advice regarding a DIY supply, which is now going for silly money (but did make a positive difference I found at the time).

[Clive]

I've not really thought much about the price but it will be right, nothing silly. It's something I have spare and just want something for it, nothing like the 80 quid I've just seen on ebay. Not sure what the postage cost will be but it's whatever the PO charges.

I'll put a plug on the wallwart and check it out sometime today.

As for a DIY PS, it's really easy. You just need a big12V transformer. I did this, it does make quite a difference.

[kcc123]

The DIY supply for the X10D is just a transformer connected with cables and plugs, then housed in an enclosure. I made couple of them a few years ago.

[DSJR]

Any regulation needed as in Paul Hynes?

[Clive]

Any regulation needed as in Paul Hynes?

This would start getting you into re-design. The X10D has a voltage doubler built into it so putting a fancy PC before this wouldn't be any use.