My rev-c has got 25-30 hours on it now, so time for some sound comments...
I've got a 300va trans, 37volt dc rails, 16volt zeners and 1uF ampohm polyprop input caps; using a passive pre.
This is as much a comparison to the power stage of an Audiolab 8000s than a comment on absolute sound quality..
Low bass is tight and well defined, mid and upper bass is less punchy (but also has less bloom) than the audiolab. The highs are clean and detailed with no grain, etching or fizz. Luvverly.
The rev-c mid perhaps lacks a bit of prescence, but is warm and natural.
Mauro's amp certainly has some magic. The last three nights I've had the intention to play one more track and have been unable to switch off before the end of the album. First it was Goldfrapps Black Cherry, then Nick Drake's Pink Moon, and last night was Giant Sand's Chore of Enchantment. Its like being mugged by music
For me though, there are still some reservations; and some of protos's comments have a ring of truth.
Again, compared to the Audiolab there is a loss of image focus ( a slight fuzziness if you will), with a sense of reduced transparency and a less open soundstage as a result. Image depth is less with the rev-c. Dynamics are good, but not explosive, probably because of my upper bass deficit.
I do think my mauro is still improving; it seems better today than yesterday. It may be the input caps; Tony Gee's site says they take a lot of burn in so we''ll see.
I also plan to try it with an active pre; I've an opa627 based thingy (like the freebird) that I'll wire in soon. I'd expect that to fix the bass dynamics.
I've also thought about component choices. I reckon a caddock with heatsink could replace the ceramic output resistor, and a caddock or vishay input 3.3k may improve transparency.
Any thoughts on this? Pointless waste of cash?
It would be good to hear more comparative comments of the sound; pluses and minuses. Pipe up folks
I've got a 300va trans, 37volt dc rails, 16volt zeners and 1uF ampohm polyprop input caps; using a passive pre.
This is as much a comparison to the power stage of an Audiolab 8000s than a comment on absolute sound quality..
Low bass is tight and well defined, mid and upper bass is less punchy (but also has less bloom) than the audiolab. The highs are clean and detailed with no grain, etching or fizz. Luvverly.
The rev-c mid perhaps lacks a bit of prescence, but is warm and natural.
Mauro's amp certainly has some magic. The last three nights I've had the intention to play one more track and have been unable to switch off before the end of the album. First it was Goldfrapps Black Cherry, then Nick Drake's Pink Moon, and last night was Giant Sand's Chore of Enchantment. Its like being mugged by music
For me though, there are still some reservations; and some of protos's comments have a ring of truth.
Again, compared to the Audiolab there is a loss of image focus ( a slight fuzziness if you will), with a sense of reduced transparency and a less open soundstage as a result. Image depth is less with the rev-c. Dynamics are good, but not explosive, probably because of my upper bass deficit.
I do think my mauro is still improving; it seems better today than yesterday. It may be the input caps; Tony Gee's site says they take a lot of burn in so we''ll see.
I also plan to try it with an active pre; I've an opa627 based thingy (like the freebird) that I'll wire in soon. I'd expect that to fix the bass dynamics.
I've also thought about component choices. I reckon a caddock with heatsink could replace the ceramic output resistor, and a caddock or vishay input 3.3k may improve transparency.
Any thoughts on this? Pointless waste of cash?
It would be good to hear more comparative comments of the sound; pluses and minuses. Pipe up folks
Thanks Brian, I am using the case from an old Blaupunkt tape deck, just haveing new faceplate made, anyway it has a fuse in the line before the switch, wich is also before trafo, so I will use that one, (it does have a further 2 on the PCB as well, guess they are typical german overengineering examples...)
Something I noticed is that the switch seems to have 2 capacitors on it, can I leave those,as they have pretty rubber insulation on ?
Also is this amp intended to be used with a preamp, despite the fact that it has a buffer stage? if not, what are the most approriate options and recommendation for volume control.
Something I noticed is that the switch seems to have 2 capacitors on it, can I leave those,as they have pretty rubber insulation on ?
Also is this amp intended to be used with a preamp, despite the fact that it has a buffer stage? if not, what are the most approriate options and recommendation for volume control.
Hi Float,
I wouldn't disagree with you at all, especially since I know you are using a passive pre. I think you will notice a marked inprovement especially in the mid-bass and midrange area with the preamp you propose to use.
I have noticed a general lack of umph and a more veiled nature to music when I use both my 10K stepped attenuator, or a simple pot. The only thing that seems to give me consistantly the best results is either to add a buffer, or use a preamp.
Certainly it still sounds very good with a passive volume control, just not as good to me. Who knows however, some may like the more "mellow" sound of the passive pre.
Good work, and thanks for the comments.
Cheers!
Russ
I wouldn't disagree with you at all, especially since I know you are using a passive pre. I think you will notice a marked inprovement especially in the mid-bass and midrange area with the preamp you propose to use.
I have noticed a general lack of umph and a more veiled nature to music when I use both my 10K stepped attenuator, or a simple pot. The only thing that seems to give me consistantly the best results is either to add a buffer, or use a preamp.
Certainly it still sounds very good with a passive volume control, just not as good to me. Who knows however, some may like the more "mellow" sound of the passive pre.
Good work, and thanks for the comments.
Cheers!
Russ
hi float.
i have found that the chip only realy becomes happy after 50 hours and more. sound absurd, i know. the bass also improved after that period and the bite was gone.
Nordic.
you can leave the switch just like it is, if it does have some caps on it will kill the switch off transients
i have found that the chip only realy becomes happy after 50 hours and more. sound absurd, i know. the bass also improved after that period and the bite was gone.
Nordic.
you can leave the switch just like it is, if it does have some caps on it will kill the switch off transients
float said:
I'd consider this , but what improvements do you think it would bring?
I thought I noticed a previous consensus that more voltage was more better? Dynamics and so on...
The problem with the higher zener values is it changes the voltage drop to the zener. Mauro has indicated that the PS for the LM318 has been planned for 12V, so it is fair to assume it is optimized for that voltage.
I tried 18V zeners and 40V rails for a while, but went back to 12V zeners and 35V rails. I will keep it that way.
Cheers!
Russ
float said:
I'd consider this , but what improvements do you think it would bring?
I thought I noticed a previous consensus that more voltage was more better? Dynamics and so on...
you would notice none. it is better at a higher voltage. a opamp should run at least on 15v. (but that is just me
)i also noticed that you were using a ampohm cap. they take forever to run in, so give it some time
Hi Guys,
I finally decided to try the my-refC using Rudi's layout (page 106 I think)
I'm using 2 x dual 25v 5amp each E/I core transformers, the 22k,47k resistors are RC55Y, input cap is Multicap RTX, 10k caps are Rubycons, the 220uf caps for the LM3886 supply pins are Nichicon PL (I personally don't like Panny FC's) the other caps are Rubycon ZA
My passive pre is a diy 22k Attenuator
I'm giving the amp a good run in on a pair of high wattage 8ohm loading resistors
I have built several other amps including Pedja's and Carlos GC's, 41khz Amp3, Pavels mosfet power follower,Avondale NCC200,WAD Kit88 tube amp and soon a ClassD amp using Hypex UCD modules, it should be interesting to compare the My-RefC, If the passive pre does not work well I also have a highly modified Naim Nac based pre-amp to try
Thanks to everybody for sharing the hard work for this amp
I finally decided to try the my-refC using Rudi's layout (page 106 I think)
I'm using 2 x dual 25v 5amp each E/I core transformers, the 22k,47k resistors are RC55Y, input cap is Multicap RTX, 10k caps are Rubycons, the 220uf caps for the LM3886 supply pins are Nichicon PL (I personally don't like Panny FC's) the other caps are Rubycon ZA
My passive pre is a diy 22k Attenuator
I'm giving the amp a good run in on a pair of high wattage 8ohm loading resistors
I have built several other amps including Pedja's and Carlos GC's, 41khz Amp3, Pavels mosfet power follower,Avondale NCC200,WAD Kit88 tube amp and soon a ClassD amp using Hypex UCD modules, it should be interesting to compare the My-RefC, If the passive pre does not work well I also have a highly modified Naim Nac based pre-amp to try
Thanks to everybody for sharing the hard work for this amp
rudi said:t, will you let us know if it actually produce sound.
Hi Rudi,
Well it seems to work ok through my IPL S3tlm ribbons
I also had a look at the outputs on a scope whilst it was connected to the 8ohm load, everything seems ok
Is that the board layout you use?
I'm hoping to do my own big shoot out over the weekend with these amps, I doubt I will post the results, I would not want to start any wars! you know how it is with this hobby
After a quick A B comparison I agree that the sound is more focussed with the 3k3 resistor
I have the amps sat on a tray at the minute until I can supply a case, it also allows for easy testing
I'm tempted to try MBR10100 Schottkies at a later stage which I have spare, they will fit on the board easy enough but first I will use the amp as standard
I have the amps sat on a tray at the minute until I can supply a case, it also allows for easy testing
I'm tempted to try MBR10100 Schottkies at a later stage which I have spare, they will fit on the board easy enough but first I will use the amp as standard
T this is the layout i am using. glad to see you are also using ribbon's. does it use a SEAS Excel for the woofer.
you can mail me if you want to be discreet. i am very interrested to hear your comparison. have a look at how i connected up the trafo's. One supplying only NEG and the other just POS
let me know
Rudi
you can mail me if you want to be discreet. i am very interrested to hear your comparison. have a look at how i connected up the trafo's. One supplying only NEG and the other just POS
let me know
Rudi
rudi said:
Hi Rudi,
The woofer is IPL's own design, I really do like these speakers but they can be very revealing especially the highs, now I'm used to Ribbon tweeters I cannot go back to normal domes
Thank you for the transformer connection advice, I'll try it later
I'll hopefully be doing the comparison tomorrow some time which I'm looking forward to, I can PM you my honest opinion if your interested, the only thing I'm interested in is the best audio quality not arguments
t. said:
I'm hoping to do my own big shoot out over the weekend with these amps, I doubt I will post the results, I would not want to start any wars! you know how it is with this hobby
I for one would really like to know your conclusions; all the amps interest me and I've heard none but the my-ref!
The forum will die without honest opinion, whether it starts a war or not. Post away.
p.s.If you choose discretion, I'd also welcome an email.
cheers
HAY GUYS WHATS GOING ON IN HERE
Ok seriously
I'm a bit late to the party as usual, so what's the status of htis project? I've read Mauro's excellent pdf files and have a pretty good grasp of the underlying principles of this circuit, and it's definately no ordinary GC!
Can anyone in the "loop" post a short summary of the project's staus so people can see where it's at without wading through 152 pages? How does it sound, comparisons to GC, is there a PCB/kit, is it still avaliable, etc...
This seem like a great project for me since I have a beater 3886 GC lying around with HS already in place
Ok seriously
I'm a bit late to the party as usual, so what's the status of htis project? I've read Mauro's excellent pdf files and have a pretty good grasp of the underlying principles of this circuit, and it's definately no ordinary GC!
Can anyone in the "loop" post a short summary of the project's staus so people can see where it's at without wading through 152 pages? How does it sound, comparisons to GC, is there a PCB/kit, is it still avaliable, etc...
This seem like a great project for me since I have a beater 3886 GC lying around with HS already in place