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Post by jimbo on Apr 26, 2020 14:31:05 GMT
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,410
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Post by Bigman80 on Apr 26, 2020 15:51:11 GMT
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Post by brian2957 on Apr 26, 2020 16:23:40 GMT
Ah...I thought it was am M55 stylus  |
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Post by jimbo on Apr 26, 2020 16:49:39 GMT
No I have one of those aswell on the Lenco.
The M44-7 actually came off my first Lenco and it has been in the loft for quite a while. Still has original stylus that sounded OK if I can remember. Think these M44-7 had quite a large power output hence they were used by DJs.
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Bigman80
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Post by Bigman80 on Apr 28, 2020 9:24:36 GMT
Just pulled the BMU out of the system to give it a once over.
It's nothing to do with boredom, but the thing has started buzzing like a hive of bees.
I'm hoping it just needs a tightening up of the transformer bolt but I am concerned it may be a loosening of the windings, which can happen over time. That and coupled with the fact it's an Airlink transformer (I dont rate them) probably means it's the latter.
I've put one of those mains conditioning multiplugs in for now, and the result is surprising.
I'll give it a proper listen later but first....off to the garage.
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Bigman80
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Post by Bigman80 on Apr 28, 2020 11:06:17 GMT
The ability to measure SMD jfets has just arrived. Need to rig up a power supply and a 100ohm resistor but it should work a treat when done. Matched FETs for the Bigbottle are not far away.  |
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Bigman80
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Post by Bigman80 on Apr 28, 2020 19:55:36 GMT
Well my plans went to Sh#t. I decided the best way forward was to remove the plastic SOT23 holder from the PCB as I wanted to use a different method of measuring than the PCB allowed. However, in removing the holder I lost two of the 3 all important contact wires inside. I have improvised but I cant getbit to work. It's now at Alan's (safely dropped in the porch) so hopefully he can revive it.  |
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Post by jimbo on Apr 28, 2020 20:19:22 GMT
What is this curious object?
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Post by sq225917 on Apr 28, 2020 20:45:21 GMT
Plastic clamp to hold a friggin tiny 3 legged component.
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Bigman80
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Post by Bigman80 on Apr 28, 2020 20:52:34 GMT
jimbo Simon is correct It's a clamp to hold the BF861C JFET which is used on the Bigbottle. The last aspect that we haven't been able to match for each channel due to the tiny size of them. This clamp has three (or did) metal contacts which can be measured using a PEAK meter. I haven't got one of those so I built a little jig on the back of the Breadboard to allow the addition of a 12v wallwart supply and also two measuring points that can be done with a standard multimeter However that all went out the window when I lost the three prongs inside it. Hopefully Alan can get the thing working..
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Post by jimbo on Apr 28, 2020 21:00:02 GMT
I see, fiddly little piece of kit. I am sure Alan will be able to sort it.
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Bigman80
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Post by Bigman80 on Apr 28, 2020 21:10:03 GMT
I see, fiddly little piece of kit. I am sure Alan will be able to sort it. Oh yes...they are not easy little bleeders to handle. I've lost loads of them lol |
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Bigman80
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Post by Bigman80 on Apr 29, 2020 19:03:17 GMT
After yesterdays disappointing Jfet clamp outcome, I decided that today i would fit a filter into my BMU. I had to shift the traffo over my an inch but it looked like the space was made for it. The decision to fit a filter (facilitated by Alan's endless stock of used bits) was based upon the sonic differences I found using a multiple plug strip with a small filter on it. Quite shockingly, the soundstage was sharper, cleaner and better defined when i took my BMU out. However, the sound lost its soul and its grunt. After a brief chat with Alan he suggested putting the filter in. I have done it and I now seem to have an uplift in clarity and soundstage precision while I have the grunt back. A great result. Next up was to remove the Khozmo Relay Volume Control. WHAT!!!! I hear you scream... Yes..you read that right. A couple of weeks back now I bought a Stepped Attenuator for the upcoming AWM buffer based preamp I am going to build. But in usual Bigman style, I couldn't wait and decided to throw it in the Neurochrome. I've been so impressed with its fluidity, detail and transparency that I dont want to take it out. So I'm not gonna. It's now a permanent fixture in the system until further notice. Busy day of messing about but the sound it hugely impressive and the work is worth it.         |
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Post by jimbo on Apr 29, 2020 19:09:14 GMT
Nice bit of engineering there Oli.
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Bigman80
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Post by Bigman80 on Apr 29, 2020 19:21:21 GMT
Nice bit of engineering there Oli. It works lol The volume knob had always been stiff as the hole wasnt central. I remedied that by fitting a surface mount bearing and drilling the hole centrally, using my newly-working-street-found pillar drill. Action is now smooth and consistent, which is how it should be. |
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Post by gninnam on Apr 29, 2020 20:33:42 GMT
Looks very nice under the hood - where was the attenuator from?
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Bigman80
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Post by Bigman80 on Apr 29, 2020 20:53:56 GMT
Looks very nice under the hood - where was the attenuator from? Thanks, I got it from ebay. It's a really good Attenuator and its less than £80! |
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Post by gninnam on Apr 29, 2020 21:16:27 GMT
Have a link as looking for a decent attenuator?
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Bigman80
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Post by Bigman80 on Apr 29, 2020 21:27:06 GMT
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Post by karma67 on Apr 30, 2020 10:56:04 GMT
As usual, mybsysyem doesn't stay settled for long. Trying out the new Stepped Attenuator Very pleased so far.   ive just gone for a 50k one,the original was 100k, hopefully it will be fine. |
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Bigman80
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Post by Bigman80 on Apr 30, 2020 11:01:44 GMT
As usual, mybsysyem doesn't stay settled for long. Trying out the new Stepped Attenuator Very pleased so far. ive just gone for a 50k one,the original was 100k, hopefully it will be fine. Didn't you have a Goldpoint one? Just give it time to open up (don't care for argument against this) as it was a bit heavy handed in the LF for the first hour or so in each position. Now its very clean and much better balanced from top to bottom. I think it's given me a better emotional connection to the music than the Khozmo did. Why, i dont know. Its certainly not giving up any transparency to the Khozmo as a trade off, which you normally find. Only thing it doesn't have is.......a remote lol. The Khozmo has made me lazy |
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Post by karma67 on Apr 30, 2020 11:50:19 GMT
yes i do have a goldpoint one,the other thing is is doesn't have a threaded middle boss by the looks of it so i'll have to find a cunning way to mount it.
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,410
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Post by Bigman80 on Apr 30, 2020 12:33:23 GMT
yes i do have a goldpoint one,the other thing is is doesn't have a threaded middle boss by the looks of it so i'll have to find a cunning way to mount it. Like this  |
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Deleted
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Post by Deleted on Apr 30, 2020 14:59:54 GMT
After yesterdays disappointing Jfet clamp outcome, I decided that today i would fit a filter into my BMU. I had to shift the traffo over my an inch but it looked like the space was made for it. The decision to fit a filter (facilitated by Alan's endless stock of used bits) was based upon the sonic differences I found using a multiple plug strip with a small filter on it. Quite shockingly, the soundstage was sharper, cleaner and better defined when i took my BMU out. However, the sound lost its soul and its grunt. After a brief chat with Alan he suggested putting the filter in. I have done it and I now seem to have an uplift in clarity and soundstage precision while I have the grunt back. A great result. Next up was to remove the Khozmo Relay Volume Control. WHAT!!!! I hear you scream... Yes..you read that right. A couple of weeks back now I bought a Stepped Attenuator for the upcoming AWM buffer based preamp I am going to build. But in usual Bigman style, I couldn't wait and decided to throw it in the Neurochrome. I've been so impressed with its fluidity, detail and transparency that I dont want to take it out. So I'm not gonna. It's now a permanent fixture in the system until further notice. Busy day of messing about but the sound it hugely impressive and the work is worth it. Must admit, I wouldn't bother with something like this myself. See little point in having the provision for 23/64 levels of attenuation, when most would never get used. My normal listening level is sort of constant. Having 3/4 levels of attenuation in reserve would be enough. I'd just wire a switch gang for 4 levels and spend the money on the 16 resistors that would actually get used. |
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,410
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Post by Bigman80 on Apr 30, 2020 16:03:13 GMT
After yesterdays disappointing Jfet clamp outcome, I decided that today i would fit a filter into my BMU. I had to shift the traffo over my an inch but it looked like the space was made for it. The decision to fit a filter (facilitated by Alan's endless stock of used bits) was based upon the sonic differences I found using a multiple plug strip with a small filter on it. Quite shockingly, the soundstage was sharper, cleaner and better defined when i took my BMU out. However, the sound lost its soul and its grunt. After a brief chat with Alan he suggested putting the filter in. I have done it and I now seem to have an uplift in clarity and soundstage precision while I have the grunt back. A great result. Next up was to remove the Khozmo Relay Volume Control. WHAT!!!! I hear you scream... Yes..you read that right. A couple of weeks back now I bought a Stepped Attenuator for the upcoming AWM buffer based preamp I am going to build. But in usual Bigman style, I couldn't wait and decided to throw it in the Neurochrome. I've been so impressed with its fluidity, detail and transparency that I dont want to take it out. So I'm not gonna. It's now a permanent fixture in the system until further notice. Busy day of messing about but the sound it hugely impressive and the work is worth it. Must admit, I wouldn't bother with something like this myself. See little point in having the provision for 23/64 levels of attenuation, when most would never get used. My normal listening level is sort of constant. Having 3/4 levels of attenuation in reserve would be enough. I'd just wire a switch gang for 4 levels and spend the money on the 16 resistors that would actually get used. Ye that's fair enough. I do tend to use quite a few steps, especially when bakeoffs happen etc but yes, 10 steps is probably more than enough. |
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Bigman80
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Posts: 16,410
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Post by Bigman80 on Apr 30, 2020 16:07:12 GMT
Just been to fetch the Jig for JFET testing. Seems that when I replaced the contacts, I hadnt paid enough attention to making sure they were level so one leg probably wasnt touching. Alan, once again, applied his expertise and it now works. I now have 2x matched BF861C to go back on my Bigbottle, which i will do tomorrow. Just for those that haven't seen a JFET, I have attached a couple of pics below.    |
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Post by sq225917 on Apr 30, 2020 16:50:45 GMT
Ha ha the Devils work.
I've just knocked up Alan a set of loading plugs with Vishay 1206 melf resistors.
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,410
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Post by Bigman80 on Apr 30, 2020 17:03:09 GMT
Ha ha the Devils work. I've just knocked up Alan a set of loading plugs with Vishay 1206 melf resistors. Oh, very posh....and fiddly lol Yes, these Jfets are the devils work but they have proved the perfect choice for this application. Cant argue. |
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Post by karma67 on Apr 30, 2020 17:05:21 GMT
Must admit, I wouldn't bother with something like this myself. See little point in having the provision for 23/64 levels of attenuation, when most would never get used. My normal listening level is sort of constant. Having 3/4 levels of attenuation in reserve would be enough. I'd just wire a switch gang for 4 levels and spend the money on the 16 resistors that would actually get used. i like your reasoning! makes me wonder why on earth i just bought one lol with that said if its anything like his phono stage it will be worth it.
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,410
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Post by Bigman80 on Apr 30, 2020 17:55:42 GMT
Must admit, I wouldn't bother with something like this myself. See little point in having the provision for 23/64 levels of attenuation, when most would never get used. My normal listening level is sort of constant. Having 3/4 levels of attenuation in reserve would be enough. I'd just wire a switch gang for 4 levels and spend the money on the 16 resistors that would actually get used. i like your reasoning! makes me wonder why on earth i just bought one lol with that said if its anything like his phono stage it will be worth it.
The VAS is a good phonostage isnt it. I thoroughly enjoyed it. |
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