I see, looks like 18AWG should be ok, the thickest enamelled I can order here in the UK is 14AWG, so I may try this also. My speakers (or ears!) won't really be happy over with 70W anyway, as I'm sat within 2 feet of my speaker most of the time (nearfield monitor duty!).
Seems crazy how such a thing like a volume control can have so many solutions, right now I think I can do far better than just a pot between DCX and amp, as the impedance will change when I adjust the volume. I'm going to have to do more research into this area, I've only just found the thread relating the the Nelson Pass B1, so it seems I've got a bit of experimentation to do - I'll try and not drag this thread further offtopic!
I like your reasoning!
I SMPS arrived today, but I have not got around to hooking it up. I need to keep an eye on the temp on my heatsink however, as I've removed the fan heatsink and replaced it with a passive computer heatsink. I'm going to hook up a fan again once I find an L7805...I guess I could be opening a can of worms with this question, but is there any difference between Belden and generic magnet wire?
I've only found 2 shops in the UK with magnet wire in stock, and it's pretty reasonable (around $20 for 1lb of wire), but I can also obtain Belden at great expense from the US.
I've ordered some 18AWG generic wire for now, but I was wondering is there a notable gain from using Belden? I don't really have an amazing set of speakers, so would the generic stuff be ok?
I love the 'variable inductor' idea also.
Last edited:
Well, there's no question that there are lots of different kinds of "copper wire." Some are copper alloys that vary in makeup. The way the wire is drawn can vary, hot or cold, speed, etc. All of these affect the molecular structure.
The speaker forums talk about "oxygen-free copper" whatever that is. I suppose the wire I bought came from China. Which may be good or bad, I don't know. Belden is a high quality manufacture with top-notch products. In other words, we know Belden is good, but we don't know if the stuff I bought is good. For the price iIpaid, I assume it is compromised in some way.
Still, we don't know how much of the difference Sendler heard is attributable to the quality of the wire and how much is because the wire was larger. We also don't know if we would hear the same difference that Sendler heard, or whether we would interpret it the same way he did.
That's one of the reasons this is DIY. Sendler's experiments are invaluable, and help to suggest interesting paths of exploration. But if you really want to know whether it will work for you in your system, you have to try it yourself.
I am convinced the air-core coils make the Sure the best amp I've ever heard. But others may miss some of the weight and body that a little "beneficial harmonic distortion" adds. It gives the sound power and impact.
If you DIY, you can tailor you system to do what you want it to do. Me, I want it to be as accurate as possible. Which is really not possible, since don't know what the musicians heard in the recording studio, and even if I did, I don't know how much of that made it to the CD.
-dr_vega
Wire
I don't have enough Belden left to make another set of coils so I don't know if it sounds better than the generic magnet wire but eventually I would like to try another roll. The Belden has a different insulator that is not solder strip-able so it is harder to terminate but may indeed sound more transparent when I compare the air toroids with the generic wire 14ga cylinders. I will need an identical set of coils to really find out how much of the difference is because of the wire. If the foil/ teflon coils sound as good as my foil/ air speaker cables, the whole question of magnet wire will be over for me anyway.
.
As far as volume control goes, I spent a lot of time trying many different styles, High End tube preamps, stepped attenuators buffered with opamps and again opamps driving class a transistors, and the best sonics are had with the cheapest solution. The passive stepped attenuator. Or second, a good pot. The whole trick to getting great sound from a passive volume control is in keeping the cables between it and the amp to a minimum/ none. That, and keeping the output impedance of the pot/ attenuator to 1/5 or better of the input impedance of the amp. I use 4k shunt style attenuators with my other amps which is about as low as you can go without loading up your sources. Right now with the Sure amps I run my modified DEQ straight in and use only digital volume control. The gain of the amps is perfect for the output of my Behringer. -0db is on the edge of dangerously loud and just begins to show signs of strain in the amps and the speakers. I will eventually change the values of the input resistors to get the amp up over 20k to make a better match with the attenuators. This might be as simple as removing R14,34.
Try a good 5k pot right on the board after the RCAs and before your input caps.
I don't have enough Belden left to make another set of coils so I don't know if it sounds better than the generic magnet wire but eventually I would like to try another roll. The Belden has a different insulator that is not solder strip-able so it is harder to terminate but may indeed sound more transparent when I compare the air toroids with the generic wire 14ga cylinders. I will need an identical set of coils to really find out how much of the difference is because of the wire. If the foil/ teflon coils sound as good as my foil/ air speaker cables, the whole question of magnet wire will be over for me anyway.
.
As far as volume control goes, I spent a lot of time trying many different styles, High End tube preamps, stepped attenuators buffered with opamps and again opamps driving class a transistors, and the best sonics are had with the cheapest solution. The passive stepped attenuator. Or second, a good pot. The whole trick to getting great sound from a passive volume control is in keeping the cables between it and the amp to a minimum/ none. That, and keeping the output impedance of the pot/ attenuator to 1/5 or better of the input impedance of the amp. I use 4k shunt style attenuators with my other amps which is about as low as you can go without loading up your sources. Right now with the Sure amps I run my modified DEQ straight in and use only digital volume control. The gain of the amps is perfect for the output of my Behringer. -0db is on the edge of dangerously loud and just begins to show signs of strain in the amps and the speakers. I will eventually change the values of the input resistors to get the amp up over 20k to make a better match with the attenuators. This might be as simple as removing R14,34.
Try a good 5k pot right on the board after the RCAs and before your input caps.
Whoo, my board has finally arrived. Works and all, though things are a bit jury rigged. In particular, I realized I have no idea how to use the binding posts...which bits should the board be sandwiched between? I also have to find some precision screw drivers for these screw headers.
The manual for the board says to use a 50k volume pot, should I go with 10k instead?
The manual for the board says to use a 50k volume pot, should I go with 10k instead?
Just a quick question about these sure amps, (same question I posted on the Lepai thread also, but just as relevant to this board)
Are the 'Overshoot Protection' shottky diodes fitted to the output stages of these amps as built by Sure...?
--They are needed there to prevent destruction of the output stage MOSFETS when driving heavily reactive or difficult loads or running the device very hard....
Are the 'Overshoot Protection' shottky diodes fitted to the output stages of these amps as built by Sure...?
--They are needed there to prevent destruction of the output stage MOSFETS when driving heavily reactive or difficult loads or running the device very hard....
I want to buy a few of these boards from Sure and would like to order the PSU's from Aure at the same time. Which of the mean well PSU's on their web site would be suitable?
I was thinking of this one but the amps seem high and it may comsume to much power?
27V DC 13A 351W Regulated Switching Power Supply_Industrial Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
The other one's I was considering were
http://http://www.sureelectronics.net/goods.php?id=455
or
24V DC 6A 145W Regulated Switching Power Supply_Industrial Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
Basic question but there's a lot of choice and i'm new to this
I was thinking of this one but the amps seem high and it may comsume to much power?
27V DC 13A 351W Regulated Switching Power Supply_Industrial Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
The other one's I was considering were
http://http://www.sureelectronics.net/goods.php?id=455
or
24V DC 6A 145W Regulated Switching Power Supply_Industrial Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
Basic question but there's a lot of choice and i'm new to this
Which of the PSU's on the Sure web site would be suitable to use with these boards?
I don't have a good understanding of PSU's but I'm looking for something that will get good power out of the board but not be too power hungry?
There maybe better choices but the three I have focused on are:
24V DC 6A 145W Regulated Switching Power Supply_Industrial Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
or
24V DC 2.1A 50.4W Regulated Switching Power Supply_Plastic Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
or
http://http://www.sureelectronics.net/goods.php?id=457
A basic question but I want to make the best choice.
I don't have a good understanding of PSU's but I'm looking for something that will get good power out of the board but not be too power hungry?
There maybe better choices but the three I have focused on are:
24V DC 6A 145W Regulated Switching Power Supply_Industrial Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
or
24V DC 2.1A 50.4W Regulated Switching Power Supply_Plastic Power Adapter_Boxed Industrial Power Adapter and Chargers and Transformers_Measure Power Adapters_Sure Electronics' Webstore
or
http://http://www.sureelectronics.net/goods.php?id=457
A basic question but I want to make the best choice.
Accuracy would be my main goal with my set up also, I plan to use the speakers that this amp powers for making music, so any "beneficial harmonic distortion" would not be what I want in this case.
I guess Belden is the yardstick here, and it is good that it is available both sides of the Atlantic.
I'm going to see how I get on with the generic magnet wire for now, with any luck my wire should arrive this week. I can see why this wire is so important tho, I think it must make more difference than speaker wire as it's filtering as well as carrying the signal.I agree with the DIY experimentation, it is great to be able to change things around like this, and because this amp is so affordable, it's nice to keep one with stock (or iron-core toroidal) inductors, this way the mods can easily be compared - with any luck my 2nd sure board should be here soon!
Interesting, I'll look forward to your thoughts on the foil/teflon combo. Am I right in assuming Belden magnet wire has red insulation? I found a non-working Charleze V2 TA2020 amp today, which has air-core inductors which uses red-wire, I'm planning to try these inductors out on the sure board, and if I can, I'll try and wind the equivalent inductors using the generic stuff that I have.
Great info, thanks. Starting with the cheapest solution sounds good to me, I'll try some 5K pot's on the amp board once they arrive. If that works out, I think a stepped attenuator would be best, as not many steps are needed, as I can use the internal gains of the DCX to achieve -10Db of attenuation without any problems.
By the looks of the schematic, could a pot be used in place of R14/R34?
I'm using a 20k pot right now, and it works fine. I guess a 10k should be ok also.
The TC2000 data sheet says the the input impedance is 2000 ohms, but I'm not really sure if this is the input impedance of the Sure board due to the resistors and capacitor on the input stage of the circuit... The schematic in the manual is pretty handy tho, I think the input impedance to 20k ohm, but don't quote me on that!
As for the binding posts, I didn't bother with them, I just used the screw terminals to hold my speaker wire, far better than binding posts IMO.
Hi, where is that quote from? I cannot find any mention of Schottky diodes in the Tk2050 datasheet or the Sure manual... This amp does not use the TA2020 chip like the Lepai does however!
Hi Mike...
I was asking, as I know there was an issue with the 2020, and as the format is very nearly the same as to the O/P stage MOSFETS and RF Filter-stages, it could also be subseptible to the same 'mode of damage' that the 2020 suffered from when the supply was near its maximum and 'difficult' loads were driven.
--A few years ago, on the Tripath website, (Long since gone....) there was a single leaf about the overshoot protection using the diodes....
I think this information about overshoot protection using the diodes is within the TA2020 datasheet, that's where I remember reading it and also seeing 8 diodes on the schematic.
I do not think this amp needs these diodes, and even if it does, you can play it safe and feed it 32v or less.
What value for output caps and Zobel
Hi,
I just bought last night a second 2 x 100W, these are pretty good.
What are you guys using for the output caps keeping in minds that I will keep the present output coils (22uH shielded type)
What I'm looking for is the value for C33, C36, C35 and also the value for the Zobel, I am aware that it is a matter of compromise but please suggest values that have given you great sounds. A while back at the beginning of this thread someone had suggest great result with 0.22uF Polyester Film cap so I already bought 20 of them, I hope I can use them
Thanks for your help.
Eric
Hi,
I just bought last night a second 2 x 100W, these are pretty good.
What are you guys using for the output caps keeping in minds that I will keep the present output coils (22uH shielded type)
What I'm looking for is the value for C33, C36, C35 and also the value for the Zobel, I am aware that it is a matter of compromise but please suggest values that have given you great sounds. A while back at the beginning of this thread someone had suggest great result with 0.22uF Polyester Film cap so I already bought 20 of them, I hope I can use them
Thanks for your help.
Eric
4X100 problems
http://www.diyaudio.com/forums/clas...ath-board-4-100w-class-d-amplifier-board.html
Lots of problems.
http://www.diyaudio.com/forums/clas...ath-board-4-100w-class-d-amplifier-board.html
Remove R14/34
Belden makes both types. Solder strip and high temp which must be scraped. My cheap stuff is solder strip and the Belden is high temp and has a darker red color.
Keep digital attenuation as close to zero as possible for the best resolution.
I haven't tried it yet because stepped attenuators can click once in a while and the TC2000 are fragile to input spikes but removing R14/34 should be a good idea if adding a volume control. The input impedance of the amp will increase from 11k to 22k and work better with the passive control. Stepped volume control is a must have in a DCX active cross setup so all of the channels can be turned up and down the same number of clicks and stay synched.
With the volume control right on the board, minimal/none wire between it and the next active stage, you might get away with 20k. No way to tell which value might sound best but to listen. Higher values are an easier load for your source/DCX. Lower values have lower output impedances which interact with any following wire less.
My first one fried, second one is fine, no problems. Sounds great right out the box. Sure are good about replacing them. They seem to fry or not. Some bugs have been fixed and the new ones seem to work.
Terry
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.