Thanks for the info about the lack of heatsinks on the original Cyrus,
I figured just the opposite...
Yes, these 200 ohm trim pots have the adjustment on the side, but
the problem is solved with no heatsink there it will be easier.
I figured just the opposite...
Yes, these 200 ohm trim pots have the adjustment on the side, but
the problem is solved with no heatsink there it will be easier.
Tell us something about the sonics Mateus
It has a pretty schematic...it may sound nice.
tell us the real thing...you are experienced with Recording Studio..including amplifiers, so, your words have weigth...at least to me they have enormous importance.
waiting for your informs.
Carlos
It has a pretty schematic...it may sound nice.
tell us the real thing...you are experienced with Recording Studio..including amplifiers, so, your words have weigth...at least to me they have enormous importance.
waiting for your informs.
Carlos
Doesn't C41 make use of Miller effect?
Nice project. I like the abandonment of the (IME useless) protection circuit. What software do you use for layouts Geoff?
Nice project. I like the abandonment of the (IME useless) protection circuit. What software do you use for layouts Geoff?
Thanks, I think Sprint-Layout was the one I was meaning to try after I saw it recommended on here as a simple package.
Where in UK are you based?
Where in UK are you based?
richie00boy said:
I tried a number of free layout programs before deciding to spend about £25 on Sprint-Layout. It is very easy to use and does everything I could ask of it, but there again I am only interested in laying out fairly simple circuits. For more complex layouts an integrated schematic capture/layout program with DRC etc would be better (and far more expensive).
At the time I bought Sprint-Layout there were two suppliers in the UK (that I could find). One (Tech Supplies in Bath) was significanctly cheaper (by about a third).
I reside on the Lancashire coast a few miles south of Blackpool.
Hello guys
Somehow my posting was just "hello guys", I kept typing and
nothing else was being written. Some touch done inadvertently caused that...
Anyway, what I have for you guys today is nothing but good news! I
finished my two Cyrus 1 amplifiers (2 channels) each as a monoblock
in view of the fact that I had 2 other amplifiers I didn't like, MOSFET
by the way.
Twenty minutes ago I fired them up with speakers, after a previous
test with dummy loads and scope and what I saw pleasured me a
lot. Square waves perfect with no ringing or any disturbance of any
kind. The response goes up up there, more than I care and the lows
look really good.
Then there went the ultimate test with speakers and music, and I
am really content with all nuances of the amplifier either on lows or highs. Lows are firm and authoritative and detail is great as well as the sound stage, summarizing, Cyrus is a great amplifier!.
Of course I didn't mind at all to be the guinea pig on this instance
because I was desperate to find a good quasi amplifier
and I couldn't get it until Geoff showed me the Cyrus.
So, to render some justice where justice is due, I want to thank
Geoff for his gracious gesture in designing the board. The amplifier is
dead silent, the ear close to the speaker I barely can hear any sound of that annoying type.
After this endeavour of mine, I am pretty happy and I recommend
this amplifier to everyone for its undeniable quality.
Somehow my posting was just "hello guys", I kept typing and
nothing else was being written. Some touch done inadvertently caused that...
Anyway, what I have for you guys today is nothing but good news! I
finished my two Cyrus 1 amplifiers (2 channels) each as a monoblock
in view of the fact that I had 2 other amplifiers I didn't like, MOSFET
by the way.
Twenty minutes ago I fired them up with speakers, after a previous
test with dummy loads and scope and what I saw pleasured me a
lot. Square waves perfect with no ringing or any disturbance of any
kind. The response goes up up there, more than I care and the lows
look really good.
Then there went the ultimate test with speakers and music, and I
am really content with all nuances of the amplifier either on lows or highs. Lows are firm and authoritative and detail is great as well as the sound stage, summarizing, Cyrus is a great amplifier!.
Of course I didn't mind at all to be the guinea pig on this instance
because I was desperate to find a good quasi amplifier
and I couldn't get it until Geoff showed me the Cyrus.
So, to render some justice where justice is due, I want to thank
Geoff for his gracious gesture in designing the board. The amplifier is
dead silent, the ear close to the speaker I barely can hear any sound of that annoying type.
After this endeavour of mine, I am pretty happy and I recommend
this amplifier to everyone for its undeniable quality.
Hi JMateus,
I'm a big fan of these amps and I'm glad yours is going well. I'd love to build one if I could only make the boards.
Anyway, You say that the lows are firm and authoritative. What amount of capacitance and transformer have you used?
Cheers,
Martin.
I'm a big fan of these amps and I'm glad yours is going well. I'd love to build one if I could only make the boards.
Anyway, You say that the lows are firm and authoritative. What amount of capacitance and transformer have you used?
Cheers,
Martin.
As a matter of interest, what output transistors did you use?
ps: I'm glad your project was a success.
ps: I'm glad your project was a success.
jmateus said:
I am very happy, too, jmateus 🙂
As you say: ... nothing but good news, guys
I am glad, because I feel I could contribute a little bit to this.
When I, in a kind and friendly manner,
did put a little push to our member Geoff
to help with construction details.
It all started with someone mentioned Cyrus one (maybe was Geoff himself)
That is to be found in Geoff execellent & wellknown audio website:
😎
The Class-A Amplifier Site - Schematics!
😎
regards, lineup
Sonusthree said:Hi JMateus,
I'm a big fan of these amps and I'm glad yours is going well. I'd love to build one if I could only make the boards.
www.futurlec.com will do you a pair for 26USD (single-sided, no soldermask or silkscreen).
They've never let me down yet.
It's a good deal for the boards, $26 for a pair. I've never used their service but I've ordered parts from them, reliable and prompt. Good
parts too.
Geoff I meant to mention the outputs yesterday, I forgot. I'm using
Sankens 2SC 3519, I think 120 V/16 amps, 4 MHz. One of the reasons
I wanted to build a quasi like this one was the fact that I bought a
few of these transistors some time ago and I didn't have any use for them, until now. They are excellent performers as I can tell. The rest
of the transistors are exactly the ones indicated on the schem, 872,
1775, MJE 243 and 253.
I'm pretty happy with the result and I have to thank you again for
for the design of the board, without it I wouldn't have built this
Cyrus.
parts too.
Geoff I meant to mention the outputs yesterday, I forgot. I'm using
Sankens 2SC 3519, I think 120 V/16 amps, 4 MHz. One of the reasons
I wanted to build a quasi like this one was the fact that I bought a
few of these transistors some time ago and I didn't have any use for them, until now. They are excellent performers as I can tell. The rest
of the transistors are exactly the ones indicated on the schem, 872,
1775, MJE 243 and 253.
I'm pretty happy with the result and I have to thank you again for
for the design of the board, without it I wouldn't have built this
Cyrus.
Hi,
the complementary pair 1386/3519 are fitted to the latest Crimson amplifiers.
Did you manage to get O, P or Y grade?
BTW
they are specified as 50MHz devices with good gain upto 5A (Pgrade guaranteed hFE>70 @ 5A).
Nice SOA and good to 70V.
Mine are 160V 15A, are your's different?
the complementary pair 1386/3519 are fitted to the latest Crimson amplifiers.
Did you manage to get O, P or Y grade?
BTW
they are specified as 50MHz devices with good gain upto 5A (Pgrade guaranteed hFE>70 @ 5A).
Nice SOA and good to 70V.
Mine are 160V 15A, are your's different?
Another thing I forgot to mention is the power supply, I didn't build
the Cyrus power supply, instead I used one that I already had, installed in each of the cabinets used for the other amp with Mosfets.
They are the simple supplies, rectifier bridge and a pair of 15,000 uf.
If I decide to do that I will implement the Cyrus supplies which were
designed for it. Will see.
the Cyrus power supply, instead I used one that I already had, installed in each of the cabinets used for the other amp with Mosfets.
They are the simple supplies, rectifier bridge and a pair of 15,000 uf.
If I decide to do that I will implement the Cyrus supplies which were
designed for it. Will see.
The 2SC3519's I have don't mention any letter Y or P, just the designation... And they are 160V/15 A, your'e right.
Funny, I just checked the spec sheet and I noticied the frequency is 50 MHz not 4... Is this possible? Not a mistake? Of course at 12 V of VCE
and 2 A of IE....
In any case it looks like an excellent transistor!
Being a quasi complementary design it only uses NPN transistors and
this is the reason why I built this amplifier.
Funny, I just checked the spec sheet and I noticied the frequency is 50 MHz not 4... Is this possible? Not a mistake? Of course at 12 V of VCE
and 2 A of IE....
In any case it looks like an excellent transistor!
Being a quasi complementary design it only uses NPN transistors and
this is the reason why I built this amplifier.
Hi Jm,
the grade designation is located on the second line.
The O, P or Y is just under the 1 of 3519.
A superb transistor, just a pity it is only 130W, but still 105W @100Vce, else I would have used them rather than MJL4281/4302 in my present builds.
I think they are better than 1943/5200 which has dropped to just 40W @100Vce.
But, do make sure your heatsink is big enough to keep them cold under all operating conditions.
the grade designation is located on the second line.
The O, P or Y is just under the 1 of 3519.
A superb transistor, just a pity it is only 130W, but still 105W @100Vce, else I would have used them rather than MJL4281/4302 in my present builds.
I think they are better than 1943/5200 which has dropped to just 40W @100Vce.
But, do make sure your heatsink is big enough to keep them cold under all operating conditions.
It is also unfair that I didn't thank Line up for his "little push" on Geoff
for the layout design. Thanks...
Another thing I forgot to mention (my memory is going to the drain) is
the answer to a question about the power transformer. Well, they are
(yes, one power supply in each cabinet) oversized for this amp, about
350 VA each, but like I said, they were already there, so...
BTW the supplies put out around 40 volts, 41, 42... Even tough the
original schematic doesn't mention the maximum permissible I take
it that 40 volts is what is prescribed for this amplifier.
Another thing is the speaker protection "that was already there also",
so, I guess the monoblocks are well prepared to withstand any
storm...
for the layout design. Thanks...
Another thing I forgot to mention (my memory is going to the drain) is
the answer to a question about the power transformer. Well, they are
(yes, one power supply in each cabinet) oversized for this amp, about
350 VA each, but like I said, they were already there, so...
BTW the supplies put out around 40 volts, 41, 42... Even tough the
original schematic doesn't mention the maximum permissible I take
it that 40 volts is what is prescribed for this amplifier.
Another thing is the speaker protection "that was already there also",
so, I guess the monoblocks are well prepared to withstand any
storm...
- Status
- Not open for further replies.