Sounds like a good start. We have found that this particular preamp really benefits from a strong power supply, meaning big caps, big transformer and high speed diodes. Sold one to Gordon Holt once, just from an A-B listening test.
I bought my FET ten/hl based on Gordon Holt's review. At the time I could not afford an upgraded supply as Gordon recommended, and I still can't. But a new supply is possibly my next project after I finish what I'm working on.
The previous FET 9/10 thread had some power supply ideas. Are there any others?
On a related subject, can anyone tell me what the proper tool is for removing the top cover screws of the FET ten/hl?
On a related subject, can anyone tell me what the proper tool is for removing the top cover screws of the FET ten/hl?
1/16" allen wrench is the size you want. In a pinch you can use a 1.5mm wrench - it's a bit undersized but will work.
---Gary
Why not run a battery power supply and be done with it. Cheaper too!
Have you compared a battery supply to a really well built conventional supply?
I confess that I haven't but I have learned that making a really good conventional AC supply isn't easy. Bigger transformers, good quality diodes, snubbers, good electrolytic caps and film bypass caps, all seem to make a difference.
Somehow, the idea of batteries never appealed to me. But I'd be interested in hearing from anyone who's done a comparison of over the top battery power to over the top AC supplies.
---Gary
My SL-10 is battery powered.I talked to MrPass about it and he said it's as good as it gets.Think about it. Zero noise and all the current you need. Preamps do not need alot of battery and mine last a month before needing a charge.
My SL-10 is battery powered.I talked to MrPass about it and he said it's as good as it gets.Think about it. Zero noise and all the current you need. Preamps do not need alot of battery and mine last a month before needing a charge.
Any more details on how you are doing this?
Take four 12 volt battery's .Run two pair in series.
Take the 24 volt positive and the 24 volt neg and find a xlr plug
And some good 16 agw wire and your set
Take the 24 volt positive and the 24 volt neg and find a xlr plug
And some good 16 agw wire and your set
Take four 12 volt battery's .Run two pair in series.
Take the 24 volt positive and the 24 volt neg and find a xlr plug
And some good 16 agw wire and your set
Could you say which batteries you are using?
Building a battery P.S. should not be a big deal for a preamp, but I had not been convinced by the approach. ..15 years ago when I lessoned to a high end battery powered preamp.
I am not sure of the model, I believe it was a Jeff Rowland or something like that, and I had not been so much impressed.
So I will maybe try this, but I do not expect a so big improvement... Contrarily, I have been, for sure, incredibly impressed by the power supply upgrade described on my website.
Since I have completed this AC power supply upgrade, I believe that the P.S is a totally under estimated part in the preamps/amps, even in the high end devices, where it is still possible to get a huge improvement.
I am not sure of the model, I believe it was a Jeff Rowland or something like that, and I had not been so much impressed.
So I will maybe try this, but I do not expect a so big improvement... Contrarily, I have been, for sure, incredibly impressed by the power supply upgrade described on my website.
Since I have completed this AC power supply upgrade, I believe that the P.S is a totally under estimated part in the preamps/amps, even in the high end devices, where it is still possible to get a huge improvement.
Building a battery P.S. should not be a big deal . . .
So I will maybe try this, but I do not expect a so big improvement...
Nounours,
I look forward to your experiments in this regard. Your experience upgrading your 10e seems to match mine, so I'd be very interested the results if you have time to experiment with battery supplies.
By the way, I think it's time for me to replace the volume/balance control in my 10e. I thought the preamp was sounding good but I did a quick experiment that tells me there is still a lot of room for improvement. I swapped out the 10e for a passive preamp using optocouplers. It's based on the Warpspeed modules that Blues mentioned in post #3. While I still think that an active preamp has a drive that passive preamps miss, there is no question that the optocoupler passive preamp had much greater transparency and detail. So I'm going to try putting better volume controls in the Threshold. And I'll add a buffer to the Warpspeed - perhaps that will give the best of both worlds.
---Gary
Steve,Please explain how a battery can be beat.I just dont see how!
You might want to think a bit about the impedance of your power supply as a function of frequency. Ideally your power supply will look like AC ground at all frequencies. If you look on the web you can find articles where this has been measured. For example - http://www.telepower.com.au/INT95b.PDF
Clearly batteries are not perfect and you'll still need to do some work to wring out the best sound.
Batteries have advantages in not being connected to the AC lines, which tend to be noisy. But they're not a panacea. And they have their own maintenance and charging headaches, which turn some of us off.
There are many roads to audio nirvana. I'm glad you've found one that you like. Humor the rest of us who chose another route.
---Gary
By the way, I think it's time for me to replace the volume/balance control in my 10e. I thought the preamp was sounding good but I did a quick experiment that tells me there is still a lot of room for improvement. I swapped out the 10e for a passive preamp using optocouplers. It's based on the Warpspeed modules that Blues mentioned in post #3. While I still think that an active preamp has a drive that passive preamps miss, there is no question that the optocoupler passive preamp had much greater transparency and detail. So I'm going to try putting better volume controls in the Threshold. And I'll add a buffer to the Warpspeed - perhaps that will give the best of both worlds.
Gary: just read again the article on my website: I have already replaced the volume control by attenuators. I strongly encourage you to do the same! After having upgraded the Power Supply, replacing the volume control by attenuator is a must have!
The Fet-10 goes to another level of excellence, details and transparency.
I have spent a lot of time to identify which attenuator I should use, both to reach the best possible sound and also to have enough space to locate it into the (small) cabinet.
As indicated in the article, I have chosen the GOLDPOINT Mini-V because:
-they are as good (if not better) than the Dact ones
-they are available in 25kohm impedance, whereas the dact only exist in 20kohm...
-the other brands are usually bigger, so they cannot be located in the cabinet.
With the GOLDPOINT mini-V, you can choose TWO mono 25kohm attenuators, and they can easily be installed in the cabinet: you just have to remove the balance control (I personnaly never use it) and you just have to slightly enlarge the axis holes on the front plate of the Fet-10, because the Goldpoint have a slightly bigger axis than the original NOBLE potentiometers.
Just refer to the Thresholdlovers article or just ask me if you have questions,
All the best,
1/16" allen wrench is the size you want. In a pinch you can use a 1.5mm wrench - it's a bit undersized but will work.
---Gary
Thanks. Having now obtained a proper 1/16 inch allen wrench, 1/16 inch is clearly the right size tool. But unfortunately I still can't get the screws out. I have the feeling the designer never intended the FET ten to be taken apart.
. . . I still can't get the screws out. I have the feeling the designer never intended the FET ten to be taken apart.
I can assure from personal experience that it's not hard to remove the screws if you've got the right tools. Have you stripped the screw head by any chance? This would be the case if the allen wrench just rotates and doesn't grip the screw. Fixing this is a bit tricky since you'd need to get a screw extractor. I measured the diameter of the screw threads and it's ~ 3/32", so you'd need an extractor that works with screws that small.
If the screw isn't stripped then you just need to use a bit of force to loosen the screw. They're torqued down and do require a bit of force to get started. After that they come out easily.
---Gary
If the screw isn't stripped then you just need to use a bit of force to loosen the screw. They're torqued down and do require a bit of force to get started. After that they come out easily.
---Gary
It's possible I may have stripped one. The others seem intractable. Will try again this afternoon and report back.
I was able to remove one screw. The tool I am using is 38603 - Bondhus 38603, 1/16 GoldGuard Plated Balldriver Screwdriver (2)
Perhaps an 'L' shaped hex wrench would be better? What I wish I had was a tool with a thick shaft and a large handle, but I've not been able to find any such thing. The tool I have feels like it is going to snap the shaft before the screws come loose.
Perhaps an 'L' shaped hex wrench would be better? What I wish I had was a tool with a thick shaft and a large handle, but I've not been able to find any such thing. The tool I have feels like it is going to snap the shaft before the screws come loose.
- Home
- Amplifiers
- Pass Labs
- Restoring a Threshold FET 10e - a few questions