Hi Russ
pretty neat stuff. i agree with you the new SACD's are much better and it pays to go that route. specially since they resolve the detail much better,
and this little amp can handle such stuff very well. now the speaker manufacturers needs to wake up and get there tweeters in line with the new standard. although most of us can't hear above 16khz. we can still feel it and it does make a difference to the sound. that is why you will find that the Bass always sounds better on a system with a good tweeter. weird. but there is a magnitude of high freq info in your bass.
just another reason for getting this amp
cheers
rudi
pretty neat stuff. i agree with you the new SACD's are much better and it pays to go that route. specially since they resolve the detail much better,
and this little amp can handle such stuff very well. now the speaker manufacturers needs to wake up and get there tweeters in line with the new standard. although most of us can't hear above 16khz. we can still feel it and it does make a difference to the sound. that is why you will find that the Bass always sounds better on a system with a good tweeter. weird. but there is a magnitude of high freq info in your bass.
just another reason for getting this amp
cheers
rudi
And you thought sound evaluation was simple??
To add another angle, frequencies above 20kHz seem to have a significant impact on perception of sound quality-see below. So it appears that there is some value in those ribbons that extend to 40kHz...
AES preprint 3207 by Oohashi et al. claims that reproduced sound above 26 kHz "induces activation of alpha-EEG (electroencephalogram) rhythms that persist in the absence of high frequency stimulation, and can affect perception of sound quality." [4]
Oohashi and his colleagues recorded gamelan to a bandwidth of 60 kHz, and played back the recording to listeners through a speaker system with an extra tweeter for the range above 26 kHz. This tweeter was driven by its own amplifier, and the 26 kHz electronic crossover before the amplifier used steep filters. The experimenters found that the listeners' EEGs and their subjective ratings of the sound quality were affected by whether this "ultra-tweeter" was on or off, even though the listeners explicitly denied that the reproduced sound was affected by the ultra-tweeter, and also denied, when presented with the ultrasonics alone, that any sound at all was being played.
From the fact that changes in subjects' EEGs "persist in the absence of high frequency stimulation," Oohashi and his colleagues infer that in audio comparisons, a substantial silent period is required between successive samples to avoid the second evaluation's being corrupted by "hangover" of reaction to the first.
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm#link6
To add another angle, frequencies above 20kHz seem to have a significant impact on perception of sound quality-see below. So it appears that there is some value in those ribbons that extend to 40kHz...
AES preprint 3207 by Oohashi et al. claims that reproduced sound above 26 kHz "induces activation of alpha-EEG (electroencephalogram) rhythms that persist in the absence of high frequency stimulation, and can affect perception of sound quality." [4]
Oohashi and his colleagues recorded gamelan to a bandwidth of 60 kHz, and played back the recording to listeners through a speaker system with an extra tweeter for the range above 26 kHz. This tweeter was driven by its own amplifier, and the 26 kHz electronic crossover before the amplifier used steep filters. The experimenters found that the listeners' EEGs and their subjective ratings of the sound quality were affected by whether this "ultra-tweeter" was on or off, even though the listeners explicitly denied that the reproduced sound was affected by the ultra-tweeter, and also denied, when presented with the ultrasonics alone, that any sound at all was being played.
From the fact that changes in subjects' EEGs "persist in the absence of high frequency stimulation," Oohashi and his colleagues infer that in audio comparisons, a substantial silent period is required between successive samples to avoid the second evaluation's being corrupted by "hangover" of reaction to the first.
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm#link6
rudi said:you are obviously not getting what i am saying here.
I think I did, but...(?!)
rudi said:
If it sounds great on your reference system, then it should be great.
On the other system the problem is elsewhere, not on the amp.
rudi said:I wanted to know what other people were experiencing when listening to it without the resolution of a DAC and ribbons.
What Dac?
If you don't specify, you will get no answer, because there are very bad Dacs around...
What ribbon?
Comparing to what dome tweeter?
Crossed-over at what frequency? What slope?
It is not easy to answer this...
rudi said:i hope i made myself clear this time.
I don't like the 'ordinary' chipamp either.
rudi said:i hope i made myself clear this time.
Well... sorta.
Nevermind.
carlosfm said:
Exactly my point - the stuff is cheap you get what you pay for.
Well the DAC is a Tessaract and i know you do not know it. it is locally developed for the serious hifi fanatic. it started as a California audio labs that were modified but the basic ingredients are PCM 63 K with OPA627 and siemens CCA valves on the out put
the ribbons are pinsh ribbons. crossing over at 900hz and is flat upto 40khz
and compared to ANY dome tweeter
italian PCB for Penasa Rev A or C
Hi all, after some mail exchange with Mauro, I'm going to launch a PCB pool for the My_Ref amp. I decided to use the Mauro original version (stereo) because is well engineered, use less part, cost les and was tested by Mauro.
The only modification I made on PCB published at the start of this 3D is a reduction of board margin on the LM3886 side, to avoid mounting interference with dissipator and some SMD pad on the copper layer, provide to solder the SMD or PTH component for rev C. I'm dealing with some local PCB manufactorer to have a professional board at the lowest cost. To do that I need minimum quantities, I and some friend of mine are too far from these required investment. Price target is less than 18euros.
If there is some italian guy interested I can arrange to have some board for the Marzaglia Flea Market, scheduled next 10th September., to avoid postal charges that are too misproportioned to the board cost.
Hi all, after some mail exchange with Mauro, I'm going to launch a PCB pool for the My_Ref amp. I decided to use the Mauro original version (stereo) because is well engineered, use less part, cost les and was tested by Mauro.
The only modification I made on PCB published at the start of this 3D is a reduction of board margin on the LM3886 side, to avoid mounting interference with dissipator and some SMD pad on the copper layer, provide to solder the SMD or PTH component for rev C. I'm dealing with some local PCB manufactorer to have a professional board at the lowest cost. To do that I need minimum quantities, I and some friend of mine are too far from these required investment. Price target is less than 18euros.
If there is some italian guy interested I can arrange to have some board for the Marzaglia Flea Market, scheduled next 10th September., to avoid postal charges that are too misproportioned to the board cost.
Latest revision of monobloc REV-ABC PCB
I finally got back to my desk and here is the result of the latest tweaks based on Mauro's suggestions.
The only major change is the 100nf bypass cap for C9. I used 5mm size pads to give flexibility(ceramic or film or whatever)
I also just tried to make it a little more tidy.
If anyone really wants another REV A run, or a REV-ABC stereo board, just let me know.
Keep this in mind, you can use two of the monobloc boards in the same space as the original first run REV A boards, but you have the advantage of being able to use two smaller heatsinks.
The extra parts for the monoblocs (just the speaker protection circuit) are not expensive parts.(about $5)
Cheers!
Russ
I finally got back to my desk and here is the result of the latest tweaks based on Mauro's suggestions.
The only major change is the 100nf bypass cap for C9. I used 5mm size pads to give flexibility(ceramic or film or whatever)
I also just tried to make it a little more tidy.
If anyone really wants another REV A run, or a REV-ABC stereo board, just let me know.
Keep this in mind, you can use two of the monobloc boards in the same space as the original first run REV A boards, but you have the advantage of being able to use two smaller heatsinks.
The extra parts for the monoblocs (just the speaker protection circuit) are not expensive parts.(about $5)
Cheers!
Russ
Attachments
Hi Russ,
please note that my PCB-pool is not intended to compete with Yours at all. You do a lot of work, the single channel board has some advantages and prices are good.
My PCB launch is Just for avoid delivery and customs expenses, and is mainly devoted to the small Italian audio DIYer community.
When I were sitting down to try to etch a PCB from the original artwork I realized that making holes and trace and all is required to have a discrete job, a professiona approach is mandatory.
So if I can pu togheter about 30 pieces I can have a professional PCB at a affordable price, top silk, 70um copper and gold finishing.
The ancient latin were used to say "nemo profeta in patria", so happens for the job of Mauro, that is having great succes outside our country. My attempt is a way to bring the boy back home.
please note that my PCB-pool is not intended to compete with Yours at all. You do a lot of work, the single channel board has some advantages and prices are good.
My PCB launch is Just for avoid delivery and customs expenses, and is mainly devoted to the small Italian audio DIYer community.
When I were sitting down to try to etch a PCB from the original artwork I realized that making holes and trace and all is required to have a discrete job, a professiona approach is mandatory.
So if I can pu togheter about 30 pieces I can have a professional PCB at a affordable price, top silk, 70um copper and gold finishing.
The ancient latin were used to say "nemo profeta in patria", so happens for the job of Mauro, that is having great succes outside our country. My attempt is a way to bring the boy back home.
plovati said:
Hi Plovati,
I have no problem with your pool at all. I was really just trying to explain my design choices.
By the way, I have shipped approximately 16 boards to Italy already, and as far as I know there was no customs issue, since I marked them as samples, not commercial.
If you would like a way to get the monoblocs out to Italians cheaper I would be glad to send a quantity(20 or so depending on demand) to an Italian distributor. Would you like to do that?
Cheers!
Russ
Hi all;
Little explanation for the My_Ref fans:
I have permitteded to Russ to build a series of PCBs, My_REF revA, built with my original gerber files and to create a BOM with the Brian help.
Creditable to their " divulgation work " a lot of DIY has been able to build my circuit, and of this has to be thankful to Russ and Brian.
I have permitteded to Plovati to build a little quantity of My_ref PCBs revA, and he has compact of the little changes to the gerber files to use the RevC. One of the motives is that at the moment Russ had ended the revA PCB and in Italy some asked this PCBs to me.
Russ hour has his "line" of PCBs on a trial basis and he has my completes approval, but interests me specify that the intellectual ownership of the circuit staies mine, and for mine select the project is of "public domin". This wants say that all the diys are able build the prototype for them uses, are able help to circumstance with the PCB and the components, but any it may performs an operation commercial without my prior consent.
In practice all are able behaviour as they want but any revindicates it may.
I want that this is clear first that are born of the problems among DIYs...
Said this, I recommend however of reference behaviour to Russ and Brian because I am what they have greater experience on this circuit ( after of me ), and they take an oath great work to promote it...
Ciao
Mauro
Little explanation for the My_Ref fans:
I have permitteded to Russ to build a series of PCBs, My_REF revA, built with my original gerber files and to create a BOM with the Brian help.
Creditable to their " divulgation work " a lot of DIY has been able to build my circuit, and of this has to be thankful to Russ and Brian.
I have permitteded to Plovati to build a little quantity of My_ref PCBs revA, and he has compact of the little changes to the gerber files to use the RevC. One of the motives is that at the moment Russ had ended the revA PCB and in Italy some asked this PCBs to me.
Russ hour has his "line" of PCBs on a trial basis and he has my completes approval, but interests me specify that the intellectual ownership of the circuit staies mine, and for mine select the project is of "public domin". This wants say that all the diys are able build the prototype for them uses, are able help to circumstance with the PCB and the components, but any it may performs an operation commercial without my prior consent.
In practice all are able behaviour as they want but any revindicates it may.
I want that this is clear first that are born of the problems among DIYs...
Said this, I recommend however of reference behaviour to Russ and Brian because I am what they have greater experience on this circuit ( after of me ), and they take an oath great work to promote it...
Ciao
Mauro
Sorry If I was not clear. I'll repeat the pourpose of my PCB manufactoring:
1. everyone can build My_Ref, that is Ip of Mauro Penasa.
2. everyone can made his own PCB etching a single side pcb with Mauro artwork.
3 to make a better job and avoiding to spend lot of time drilling holes, professional photoplotting and milling is required
4. to have it, one needs minimum quantities
5. If I can sell 25-30 board with few euro markup, I can cover the production tooling
6. If the manufactorer is local, all the people interested that lives nearly can save postage cost
No other consideration behind my choiche that have my copy of MyRef made better at an reasonable cost and helping some more to build their copy.
Too late to stop the machines, I'll going to get the first and last pcb lot for MyRef. Is some want it let me known. After this run, production tooling will be at Mauro disposal.
1. everyone can build My_Ref, that is Ip of Mauro Penasa.
2. everyone can made his own PCB etching a single side pcb with Mauro artwork.
3 to make a better job and avoiding to spend lot of time drilling holes, professional photoplotting and milling is required
4. to have it, one needs minimum quantities
5. If I can sell 25-30 board with few euro markup, I can cover the production tooling
6. If the manufactorer is local, all the people interested that lives nearly can save postage cost
No other consideration behind my choiche that have my copy of MyRef made better at an reasonable cost and helping some more to build their copy.
Too late to stop the machines, I'll going to get the first and last pcb lot for MyRef. Is some want it let me known. After this run, production tooling will be at Mauro disposal.
Thanks Mauro,
I would like to make the following observations, the only reason boards/kits of the MyRef design aren't currently available for sale to the DIY community from Brian and I is simply that we have listened to the community and changed the PCB to suite the broadest possible audience based on the feedback we received, and also to accomodate new suggestions from Mauro himself.
I believe we are doing the responsible thing in getting a small prototype run completed before releasing the PCB to the whole community. We want to be as sure as we can be that the PCB has no critical issues to be addressed.
That said, based on experience with Rev A, B and now Rev C the PCBs will be well worth the wait. There just is no way for the DIY designer to get things moving too fast with multilayer boards, as you are at the mercy of the manufacturer.
That is one downside to multilayer designs, I cannot (well not currently at least) prototype them from home.
The single sided design is finished, and I have even made the PDFs available for free use in the same spirit in which Mauro made the design available to us.
Thanks to all of you who make the hobby fun for me, and have helped make this application better.
Cheers!
Russ
I would like to make the following observations, the only reason boards/kits of the MyRef design aren't currently available for sale to the DIY community from Brian and I is simply that we have listened to the community and changed the PCB to suite the broadest possible audience based on the feedback we received, and also to accomodate new suggestions from Mauro himself.
I believe we are doing the responsible thing in getting a small prototype run completed before releasing the PCB to the whole community. We want to be as sure as we can be that the PCB has no critical issues to be addressed.
That said, based on experience with Rev A, B and now Rev C the PCBs will be well worth the wait.
There just is no way for the DIY designer to get things moving too fast with multilayer boards, as you are at the mercy of the manufacturer. That is one downside to multilayer designs, I cannot (well not currently at least) prototype them from home.
The single sided design is finished, and I have even made the PDFs available for free use in the same spirit in which Mauro made the design available to us.
Thanks to all of you who make the hobby fun for me, and have helped make this application better.
Cheers!
Russ
Plovati,
Best of luck with your Italian PCB run. As I stated previously, I think it is a fine thing to do.
I would reiterate my offer to ship bundles of PCBs to members in other countries if shipping is an issue. This of course would be for the monobloc design and any future work. I would simply work with one member from that country and work out the details with them.
I am a pretty accomodating guy.
Cheers!
Russ
Best of luck with your Italian PCB run. As I stated previously, I think it is a fine thing to do.
I would reiterate my offer to ship bundles of PCBs to members in other countries if shipping is an issue. This of course would be for the monobloc design and any future work. I would simply work with one member from that country and work out the details with them.
I am a pretty accomodating guy.
Cheers!
Russ
Member
Joined 2003
Part# 223-8897 with 500VA has enough power for a 4 channel amp. I believe that in order to get 25-0-25 you would wire black and yellow together for 0v, and 25V will be your red and orange wires (180 degrees out of phase, of course). If you are using Mauro's 2 channel boards, there is two connections for 0V so you don't have to physically tie the black and yellow wires together, they can both be connected to the board with Faston connectors.
Production dates.
I am hoping that Brian and I can start taking orders in the next few weeks. It will be soon after we get the first prototypes built. The PCBs for those betas should be to me in the next few days, and the rest of the beta testers in the next week or so after that (depending on where they are shipping to).
Cheers,
Russ
I am hoping that Brian and I can start taking orders in the next few weeks. It will be soon after we get the first prototypes built. The PCBs for those betas should be to me in the next few days, and the rest of the beta testers in the next week or so after that (depending on where they are shipping to).
Cheers,
Russ