Pumpkin sturtup problem
Hi Alex! Today i have started the pumpkin and i have detected a annoying noise, i have detected from my CRO (the picture shows both channels) a hi frequency noise,but what my ears hear is more like a tone of 100 Hz square wave, strange but true!
I have to tell you that I used the molex connectors, and I think that the connections with the top of the pcb are probably not ok, so I had to make a ground bridge on below pcb, as picture shows.
I also tried to disconnect the input connector and I have to say that the noise is slightly diminished but not disappeared!
I also tell you that when i put signal it i ears the sound ok !No distortion ..but when i turn down the volume the noise is there to break my balls!
I have already set Wr1 and Wr2 and this all ok and i also add resistor for better DC offset stability(see picture).Please can you send me a diagram with the references of voltage?
Please Alex help me!
Hi Alex! Today i have started the pumpkin and i have detected a annoying noise, i have detected from my CRO (the picture shows both channels) a hi frequency noise,but what my ears hear is more like a tone of 100 Hz square wave, strange but true!
I have to tell you that I used the molex connectors, and I think that the connections with the top of the pcb are probably not ok, so I had to make a ground bridge on below pcb, as picture shows.
I also tried to disconnect the input connector and I have to say that the noise is slightly diminished but not disappeared!
I also tell you that when i put signal it i ears the sound ok !No distortion ..but when i turn down the volume the noise is there to break my balls!
I have already set Wr1 and Wr2 and this all ok and i also add resistor for better DC offset stability(see picture).Please can you send me a diagram with the references of voltage?
Please Alex help me!
Attachments
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Hi Alex !Just for your information i failed to tell you that I had already tried the pumpkin before putting it in the cabinet, so.. simply connect the transformer, preamp and psu, and of course signal in and signal out, and I had already noticed that annoying background noise.
I will give you more informations in your PM.
Thanks and good morning.
Antonio
I will give you more informations in your PM.
Thanks and good morning.
Antonio
Pumpkin noise upgrade!
Hi Alex! Trying also the craziest things to solve the problem, I finally solved!
I removed R21 10k and it all worked out!
Then i decided to investigate and i found out that you also designed a version of Pumpkin using in place of R21 ... U1 LM336Z-5V
http://www.diyaudio.com/forums/pass-labs/103130-pumpkin-preamp-perfect-f4.html
Question... What should I do now leave everything just as it is now, or change something?
Removing R21 can involve some variation on the frequency response / stability of the circuit, or ......
I feel comfortable, listen to music and drink wine?
I hope that this discovery could also help other people in this forum!
Greetings to all.
Hi Alex! Trying also the craziest things to solve the problem, I finally solved!
I removed R21 10k and it all worked out!
Then i decided to investigate and i found out that you also designed a version of Pumpkin using in place of R21 ... U1 LM336Z-5V
http://www.diyaudio.com/forums/pass-labs/103130-pumpkin-preamp-perfect-f4.html
Question... What should I do now leave everything just as it is now, or change something?
Removing R21 can involve some variation on the frequency response / stability of the circuit, or ......
I feel comfortable, listen to music and drink wine?
I hope that this discovery could also help other people in this forum!
Greetings to all.
Hi at all! I noticed that there are several differences between the schematic 1 ( that reflects the reality of my pcb) and schematic 2 .
I noticed that i reconnecting R21 but bringing R22 from 47 to 220 ohm things
got better, then I also connected the base of Q9 between D4 and D5.
But to be able to adjust the offset between -out and +out i had increase
WR1 from 47 to 220 ohm.
Now Noise is OK! (please see shematic 3)
Strangely I have a gain of 4 instead of 4.7 using R5 and R6 47K and leaving R1
and R3 10K, I also changed C1 and C2 from 5p to 10p.
I think everything I've done.
Now i need a greater extent in the high frequencies, I realized that my Pumkin
vs my Emerson is less extensive on high.
Please can you give me some advice for more extension?
I believe that pumpkin can give more.
I noticed that i reconnecting R21 but bringing R22 from 47 to 220 ohm things
got better, then I also connected the base of Q9 between D4 and D5.
But to be able to adjust the offset between -out and +out i had increase
WR1 from 47 to 220 ohm.
Now Noise is OK! (please see shematic 3)
Strangely I have a gain of 4 instead of 4.7 using R5 and R6 47K and leaving R1
and R3 10K, I also changed C1 and C2 from 5p to 10p.
I think everything I've done.
Now i need a greater extent in the high frequencies, I realized that my Pumkin
vs my Emerson is less extensive on high.
Please can you give me some advice for more extension?
I believe that pumpkin can give more.
Attachments
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Tony
I was working tonight (some mumbo jumbo which can be done just between day -shifts) and just arrived from trip , back home ;
I need to catch few hours of sleep
whatever - it seems you had difficulties reading Cook Book - (sorry - I'm ignorant peasant , knowing just few words of Italian , so I couldn't make Italian version
) , so you obviously messed up something , somewhere
most left schematic is last , valid one , while middle (and most right ) one are somewhere from thread , during testing and developing
whatever - it seems you solved those issues , except lack of highs , which I'm finding somewhat doubtful ; accoring to AR2's measurements - Pumpkin is some 0,5db down on 20KHz ( with highest gain setting - for F4) , but that's nothing comparing to our hearing capability , considering age
will take a look at e-mail I got this moment from you , and write what I have
now I need to nap , my eyes are already somewhere else
I was working tonight (some mumbo jumbo which can be done just between day -shifts) and just arrived from trip , back home ;
I need to catch few hours of sleep
whatever - it seems you had difficulties reading Cook Book - (sorry - I'm ignorant peasant , knowing just few words of Italian , so I couldn't make Italian version
) , so you obviously messed up something , somewhere most left schematic is last , valid one , while middle (and most right ) one are somewhere from thread , during testing and developing
whatever - it seems you solved those issues , except lack of highs , which I'm finding somewhat doubtful ; accoring to AR2's measurements - Pumpkin is some 0,5db down on 20KHz ( with highest gain setting - for F4) , but that's nothing comparing to our hearing capability , considering age
will take a look at e-mail I got this moment from you , and write what I have
now I need to nap , my eyes are already somewhere else
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Tony
I was working tonight (some mumbo jumbo which can be done just between day -shifts) and just arrived from trip , back home ;
I need to catch few hours of sleep
whatever - it seems you had difficulties reading Cook Book - (sorry - I'm ignorant peasant , knowing just few words of Italian , so I couldn't make Italian version
most left schematic is last , valid one , while middle (and most right ) one are somewhere from thread , during testing and developing
whatever - it seems you solved those issues , except lack of highs , which I'm finding somewhat doubtful ; accoring to AR2's measurements - Pumpkin is some 0,5db down on 20KHz ( with highest gain setting - for F4) , but that's nothing comparing to our hearing capability , considering age
will take a look at e-mail I got this moment from you , and write what I have
now I need to nap , my eyes are already somewhere else
Ok! Alex i will wait!Please when you will open again your eyes ,please don't forget to me,and .....do not sleep long as a VAMPIRE!
You aren't ignorant peasant ,you are a big man but as all big man you are often busy!
Please is possible some others reference voltage point?
I'm excited as a teenager at his first time with the WOMAN!
I wish to close the Pumpkin Tomorrow ,and listen to it with my friends Saturday night .
Come on Alex!
Thanks!
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Pumpkin
Hi! I just finished testing the frequency response of the Pumpkin.
It is practically flat up to 30Khz, then starts a slight but gradual descent but I would say it is very good up to about 100 KHz.
Now I just want to be sure that everything is working fine in my Pumpkin ,so ..i can finally close the lid and start enjoying its sound!
Alex i have measured Vb of Q9 refered at gnd and it is 32V, is it ok?
What other measures should I do to sleep soundly?
Thanks
Hi! I just finished testing the frequency response of the Pumpkin.
It is practically flat up to 30Khz, then starts a slight but gradual descent but I would say it is very good up to about 100 KHz.
Now I just want to be sure that everything is working fine in my Pumpkin ,so ..i can finally close the lid and start enjoying its sound!
Alex i have measured Vb of Q9 refered at gnd and it is 32V, is it ok?
What other measures should I do to sleep soundly?
Thanks
Pumpkin noise upgrade OK! Now the choice of output capacitors
Hi Alex! Yesterday I was finally able to listen the Pumpkin!
I must start by saying that I have not checked the voltage references that you sent me and which relate to Q9.
I can only tell you what the Pumpkin is GREAT!
In fact I think it deserve C4 and C5 ( currently Arcotronics 10uf )
10uF 10F 10000nF 10000000pF 250V POLIPROPILENE MKP ARCOTRONICS 5% - Elettronica Conveniente
I would to replace with MCAP Evo, please see its datasheet.
http://www.mundorf.com/downloads/MUNDORF_Hifi_Studio_Catalog_2012.pdf
I have a question.... What do you recommend for the Pumpkin, MCAP EVO
aluminum or MCAP EVO aluminum Oil?
I still have to tell you that I have already done to bypass C4 and C5 with
polycarbonate (please see ERO MKC 1860 datasheet)
MKC 1860 datasheet and application note, data sheet, circuit, pdf, cross reference | Datasheet Archive
Please Alex can you give me some advise for this delicate choise?
Thanks in advance
Hi Alex! Yesterday I was finally able to listen the Pumpkin!
I must start by saying that I have not checked the voltage references that you sent me and which relate to Q9.
I can only tell you what the Pumpkin is GREAT!
In fact I think it deserve C4 and C5 ( currently Arcotronics 10uf )
10uF 10F 10000nF 10000000pF 250V POLIPROPILENE MKP ARCOTRONICS 5% - Elettronica Conveniente
I would to replace with MCAP Evo, please see its datasheet.
http://www.mundorf.com/downloads/MUNDORF_Hifi_Studio_Catalog_2012.pdf
I have a question.... What do you recommend for the Pumpkin, MCAP EVO
aluminum or MCAP EVO aluminum Oil?
I still have to tell you that I have already done to bypass C4 and C5 with
polycarbonate (please see ERO MKC 1860 datasheet)
MKC 1860 datasheet and application note, data sheet, circuit, pdf, cross reference | Datasheet Archive
Please Alex can you give me some advise for this delicate choise?
Thanks in advance
I just started typing reply (to same questions) in private e-mail , but I can do it here
however - I'm not cap junkie ;
you don't need to be the one , too - especially when SUSY circuit is in question (there is sort of nulling possible distortions in cap , from side to side)
use decent caps which aren't costing you your left kidney , bypass them with proper MKC , and enjoy
let me propose something - use it as now ( bypassed Arcotronics with MKC) , and look at ebay for bargains of really exotic caps
or use wakoo Russian ones - teflon or PIO (they write МБГ on some of them ) ........ even if you need to mount biggie ones with some ingenuity
that way you'll enjoy both in finding them ..... and using them
however - I'm not cap junkie ;
you don't need to be the one , too - especially when SUSY circuit is in question (there is sort of nulling possible distortions in cap , from side to side)
use decent caps which aren't costing you your left kidney , bypass them with proper MKC , and enjoy
let me propose something - use it as now ( bypassed Arcotronics with MKC) , and look at ebay for bargains of really exotic caps
or use wakoo Russian ones - teflon or PIO (they write МБГ on some of them ) ........ even if you need to mount biggie ones with some ingenuity
that way you'll enjoy both in finding them ..... and using them
High gain - R5/R1 and R6/R3 150k/10k, C1,C2 = 3,3pf.
What I hear sounds like this.
I've been trying a lot of different grounding schemes, didn't change anything. I replaced the Shuntys with Salas' shunt reguators. The chirping sound changes, gets shorter, there is more or less time between the sounds but it keeps coming back.
Pictures... currently there is just a pile of parts because I took it apart to install the offset fix. This was my test setup some time ago:
What I hear sounds like this.
I've been trying a lot of different grounding schemes, didn't change anything. I replaced the Shuntys with Salas' shunt reguators. The chirping sound changes, gets shorter, there is more or less time between the sounds but it keeps coming back.
Pictures... currently there is just a pile of parts because I took it apart to install the offset fix. This was my test setup some time ago:
An externally hosted image should be here but it was not working when we last tested it.
after "offset fix" you still have oscillation , you need to take care of few things :
-all signal traces ( I mean wires ) need to be twisted or shielded , except those really short one
-same for all power carrying wires ; both Shunty and Salas reg (even if sort of made with different approach) are better when complemented with properly laid out wiring
-try higher value for C1 & C2 ( 4p7-5p1 for starters , but no more than 6p8 , considering 150K as feedback resistor
-if that not help , put RC cell , made of 1K resistor and 2n7 in series - between collectors of Q3 and Q4
-all signal traces ( I mean wires ) need to be twisted or shielded , except those really short one
-same for all power carrying wires ; both Shunty and Salas reg (even if sort of made with different approach) are better when complemented with properly laid out wiring
-try higher value for C1 & C2 ( 4p7-5p1 for starters , but no more than 6p8 , considering 150K as feedback resistor
-if that not help , put RC cell , made of 1K resistor and 2n7 in series - between collectors of Q3 and Q4
