Parts package
Dear Hugh,
Please count me in for the parts package also. (Sl No 3)
--Annaji
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www.samritatrust.org
Dear Hugh,
Please count me in for the parts package also. (Sl No 3)
--Annaji
-----------------
www.samritatrust.org
More now added to the list, we are now at 46 boards, and still building. For those interested in the parts, I have added '+P' to the number of boards ordered:
2+P JoMo Adelaide SA Australia
2 Ian Finch Coffs Harbour NSW Australia
2+P Gennaji Hyderabad India
2 Ken Lewis LA USA
2 Ron Russell Kent UK
2 John Kenny Dublin Ireland
2 Francis Morrin Dublin Ireland
2+P Vitalica Bucharest Romania
2 Erik Deinum Groningen Netherlands
2+P Keith Correa ? India
2 Igor Polyakov California (city?) USA
2 Steve (aka SRH) Whangarei New Zealand
2+P George (aka JKC) Calgary Canada
2 Anthony Mills Gold Coast Australia
2 Dinesh (aka Chlorofille) Christchurch New Zealand
2 Colin S. (?) (city?) NSW Australia
2 Chris Powell (?) Hong Kong China
2+P Danny (?) Lierde Belgium
2 Sonnya (?) City (?) Denmark
4+P Jozua Cape Town South Africa
2 JT (? aka Sandyhooker) City (?) Arizona USA
2+P Ejam (?) City (?) Queensland Australia
Additional parts supplied for those (at five on this list) with '+P' are:
1. 2x2SK170BL input jfet
2. 2xZVP2110G VAS mosfet
3. 2xDN2530 bootstrap mosfet (TO92)
4. 2xLag comp and 2xPhase lead silver micas
This could be a very successful project, here's hoping!!
Hugh
2+P JoMo Adelaide SA Australia
2 Ian Finch Coffs Harbour NSW Australia
2+P Gennaji Hyderabad India
2 Ken Lewis LA USA
2 Ron Russell Kent UK
2 John Kenny Dublin Ireland
2 Francis Morrin Dublin Ireland
2+P Vitalica Bucharest Romania
2 Erik Deinum Groningen Netherlands
2+P Keith Correa ? India
2 Igor Polyakov California (city?) USA
2 Steve (aka SRH) Whangarei New Zealand
2+P George (aka JKC) Calgary Canada
2 Anthony Mills Gold Coast Australia
2 Dinesh (aka Chlorofille) Christchurch New Zealand
2 Colin S. (?) (city?) NSW Australia
2 Chris Powell (?) Hong Kong China
2+P Danny (?) Lierde Belgium
2 Sonnya (?) City (?) Denmark
4+P Jozua Cape Town South Africa
2 JT (? aka Sandyhooker) City (?) Arizona USA
2+P Ejam (?) City (?) Queensland Australia
Additional parts supplied for those (at five on this list) with '+P' are:
1. 2x2SK170BL input jfet
2. 2xZVP2110G VAS mosfet
3. 2xDN2530 bootstrap mosfet (TO92)
4. 2xLag comp and 2xPhase lead silver micas
This could be a very successful project, here's hoping!!
Hugh
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Hugh
With so few components I am keen to see how this amps sounds with exotic resisters and caps. At this stage I am thinking of Mundorf electrolytics for the PSU and Mundorf Gold for the 1 uF caps.
I have have found the Riken resistors to be very detailed whereass the Dale resistors can be very musical but missing in fine inner detail. The Auricaps nice but not in the same league as the Mundorf silvers or gold.
Hugh if you going to solder in the critical parts it will be very nice for noobs like me. Especially as I subcontract most of my serious DIY projects.
What I find particulary apealing is the simplicity of the design and hopefully ease of repair. Most of my commerical amps have been build halfway around the world and everytime they break it costs a arm and leg - that is if the agent is prepared to support you... Hopefully this design can address that issue.
Regards
Jozua
With so few components I am keen to see how this amps sounds with exotic resisters and caps. At this stage I am thinking of Mundorf electrolytics for the PSU and Mundorf Gold for the 1 uF caps.
I have have found the Riken resistors to be very detailed whereass the Dale resistors can be very musical but missing in fine inner detail. The Auricaps nice but not in the same league as the Mundorf silvers or gold.
Hugh if you going to solder in the critical parts it will be very nice for noobs like me. Especially as I subcontract most of my serious DIY projects.
What I find particulary apealing is the simplicity of the design and hopefully ease of repair. Most of my commerical amps have been build halfway around the world and everytime they break it costs a arm and leg - that is if the agent is prepared to support you... Hopefully this design can address that issue.
Regards
Jozua
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Hi Hugh,
Been following the PCB development closely - looks very nice.
I'm quite tempted to build fetzilla and was looking for suitable heatsinks/cases first.... Did you have any particular chassis in mind for the board? I found this which looks very slightly too small for the board as it stands:
Keep it Simple, Silent and Smart - C3LH-B
Seemed to compare quite well price wise against buying a pair of heatsinks and a nice looking box. Could well be insufficient degC/W - opinions welcome.
Anyway - just thought I'd float the idea of having a chassis in mind for the board that was relatively easily available and not horribly expensive.
Regards,
Jonathan.
Been following the PCB development closely - looks very nice.
I'm quite tempted to build fetzilla and was looking for suitable heatsinks/cases first.... Did you have any particular chassis in mind for the board? I found this which looks very slightly too small for the board as it stands:
Keep it Simple, Silent and Smart - C3LH-B
Seemed to compare quite well price wise against buying a pair of heatsinks and a nice looking box. Could well be insufficient degC/W - opinions welcome.
Anyway - just thought I'd float the idea of having a chassis in mind for the board that was relatively easily available and not horribly expensive.
Regards,
Jonathan.
Thank you. I have been watching this thread everyday and the parent thread as well. I have all parts for Juma's variation of the F5, including the Toshiba TO220 Output MOSFETs. Only don't have the heatsinks. So I have been wondering how the amp being developed in this thread will compare with Juma's F5; not having built either, I wouldn't know. My speakers are Fostex168SigmaES. So I'll wait a while longer along the sidelines.
Hi Jozua,
Hmm, Riken resistors and Mundorf caps, this could be VERY expensive.
My thoughts are that certain resistors have directional properties, the Rikens included, and this changes operating points and promotes H2 and H4, particularly when used in the fb path. It is possible, and indeed has been done to a minor extent in this circuit, to tailor the distortion profile for a more musical spectrum. You may in fact overdo it with fancy resistors, but then again, it might sound better. Don't know for sure, you'd have to build and compare.
All caps in this circuit have a polarising DC voltage across them. This is quite intentional. This stresses the dielectric with an electric field, loading it up and taking it out of its non-linear region, and makes for less distortion. In my experience boutique caps only make a difference if there is no DC across them; industry grade caps sound just fine with DC polarisation. I have tried the various comparisons using teflons (Sonicaps), Mundorfs, and other pricey components. These caps work very well in long tailed pair input stages, where the DC polarising voltages are typically about 0.1V, virtually zero.
George,
Those cases look great. If anything, their thermal rating is too high! The optimum would be two toroidal trafos, each rated to 160VA and 25-0-25Vac secondaries. These could easily fit in the center of the case, with the amp boards mounted flat against the inside base of the heatsinks, left and right. There would be plenty of room, and thermal capacity of each sink would like be around 0.45C/W. Accordingly, with 500mA quiescent, you would be dissipating 36W in each channel, giving around a 17C rise above ambient. On a day of 30C this would be 47C, which is within my preferred max of 55C and should give long MTBF for the output stage.
The TO247 Exicons look just fine and the reduced saturation voltage would possibly improve clip slightly, giving a few more watts. Nice big footprint too, ideal for convection cooled heatsinks.
Keith, Vitalica and Danny, I've added your parts preference to the list at Post #63 on page 7.
Folks, I have not yet computed the time to add the VAS to the board and the various parts prices and shipping costs yet, so can't give the additional cost. But it should be quite minimal as I'm not trying to make a profit here.
Cheers,
Hugh
Hmm, Riken resistors and Mundorf caps, this could be VERY expensive.
My thoughts are that certain resistors have directional properties, the Rikens included, and this changes operating points and promotes H2 and H4, particularly when used in the fb path. It is possible, and indeed has been done to a minor extent in this circuit, to tailor the distortion profile for a more musical spectrum. You may in fact overdo it with fancy resistors, but then again, it might sound better. Don't know for sure, you'd have to build and compare.
All caps in this circuit have a polarising DC voltage across them. This is quite intentional. This stresses the dielectric with an electric field, loading it up and taking it out of its non-linear region, and makes for less distortion. In my experience boutique caps only make a difference if there is no DC across them; industry grade caps sound just fine with DC polarisation. I have tried the various comparisons using teflons (Sonicaps), Mundorfs, and other pricey components. These caps work very well in long tailed pair input stages, where the DC polarising voltages are typically about 0.1V, virtually zero.
George,
Those cases look great. If anything, their thermal rating is too high! The optimum would be two toroidal trafos, each rated to 160VA and 25-0-25Vac secondaries. These could easily fit in the center of the case, with the amp boards mounted flat against the inside base of the heatsinks, left and right. There would be plenty of room, and thermal capacity of each sink would like be around 0.45C/W. Accordingly, with 500mA quiescent, you would be dissipating 36W in each channel, giving around a 17C rise above ambient. On a day of 30C this would be 47C, which is within my preferred max of 55C and should give long MTBF for the output stage.
The TO247 Exicons look just fine and the reduced saturation voltage would possibly improve clip slightly, giving a few more watts. Nice big footprint too, ideal for convection cooled heatsinks.
Keith, Vitalica and Danny, I've added your parts preference to the list at Post #63 on page 7.
Folks, I have not yet computed the time to add the VAS to the board and the various parts prices and shipping costs yet, so can't give the additional cost. But it should be quite minimal as I'm not trying to make a profit here.
Cheers,
Hugh
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Folks,
Now at 48 boards, this is about to cross the viable line at 50 so we are close. With more than a week remaining until Greg verifies component choices, things are looking good. I have a few parts additions, as follows:
2+P JoMo Adelaide SA Australia
2+P Ian Finch Coffs Harbour NSW Australia
2+P Gennaji Hyderabad India
2 Ken Lewis LA USA
2 Ron Russell Kent UK
2+P John Kenny Dublin Ireland
2+P Francis Morrin Dublin Ireland
2+P Vitalica Bucharest Romania
2+P Erik Deinum Groningen Netherlands
2+P Keith Correa ? India
2 Igor Polyakov California (city?) USA
2 Steve (aka SRH) Whangarei New Zealand
2+P George (aka JKC) Calgary Canada
2 Anthony Mills Gold Coast Australia
2+P Dinesh (aka Chlorofille) Christchurch New Zealand
2 Colin S. (?) (city?) NSW Australia
2 Chris Powell (?) Hong Kong China
2+P Danny (?) Lierde Belgium
2 Sonnya (?) City (?) Denmark
4+P Jozua Cape Town South Africa
2 JT (? aka Sandyhooker) City (?) Arizona USA
2+P Ejam (?) City (?) Queensland Australia
2+P Nicola City (?) Vincenza Italy
Additional parts supplied for those (at five on this list) with '+P' are:
1. 2 x 2SK170BL input jfet
2. 2 x ZVP2110G VAS mosfet
3. 2 x DN2530 bootstrap mosfet (TO92)
4. 2 x Lag comp and 2xPhase lead silver micas
Sam, you ask about comparisons with Juma's F5. I assume you mean this circuit?
http://www.diyaudio.rs/index.php?ap...ch_rel_module=post&attach_id=11101[Juma's F5]
I cannot say until I hear it, and would hope Greg might respond, however, he may not have heard Juma's circuit either. I would suspect rather similar because both are single ended, fb amps with lateral fet output stages. There are differences due to the lower loop gain, however, because bipolars have far higher transconductance and this increase the feedback level. I would say that the lower the loop gain, the more natural sounding the amp generally becomes. Even so, comparisons are very difficult, since people like different things. I'm sorry I can't say more, but I can say that the FETzilla should be extremely easy to listen to, very resolving, and a little warm.
George, you can use one larger trafo for both modules without issue. This saves money and is practical. You will neeed to duplicate each secondary winding, so start and finish each have two wires to connect to corresponding power supplies on each module. (That is, one secondary winding to supply both positive power rails, left module and right module, and the other secondary winding supplying both negative power rails, left module and right module.) However, and again IME, this may lead to slightly less image stability, where you will have a less defined left right image. On most music, this won't be noticeable.
Cheers,
Hugh
Now at 48 boards, this is about to cross the viable line at 50 so we are close. With more than a week remaining until Greg verifies component choices, things are looking good. I have a few parts additions, as follows:
2+P JoMo Adelaide SA Australia
2+P Ian Finch Coffs Harbour NSW Australia
2+P Gennaji Hyderabad India
2 Ken Lewis LA USA
2 Ron Russell Kent UK
2+P John Kenny Dublin Ireland
2+P Francis Morrin Dublin Ireland
2+P Vitalica Bucharest Romania
2+P Erik Deinum Groningen Netherlands
2+P Keith Correa ? India
2 Igor Polyakov California (city?) USA
2 Steve (aka SRH) Whangarei New Zealand
2+P George (aka JKC) Calgary Canada
2 Anthony Mills Gold Coast Australia
2+P Dinesh (aka Chlorofille) Christchurch New Zealand
2 Colin S. (?) (city?) NSW Australia
2 Chris Powell (?) Hong Kong China
2+P Danny (?) Lierde Belgium
2 Sonnya (?) City (?) Denmark
4+P Jozua Cape Town South Africa
2 JT (? aka Sandyhooker) City (?) Arizona USA
2+P Ejam (?) City (?) Queensland Australia
2+P Nicola City (?) Vincenza Italy
Additional parts supplied for those (at five on this list) with '+P' are:
1. 2 x 2SK170BL input jfet
2. 2 x ZVP2110G VAS mosfet
3. 2 x DN2530 bootstrap mosfet (TO92)
4. 2 x Lag comp and 2xPhase lead silver micas
Sam, you ask about comparisons with Juma's F5. I assume you mean this circuit?
http://www.diyaudio.rs/index.php?ap...ch_rel_module=post&attach_id=11101[Juma's F5]
I cannot say until I hear it, and would hope Greg might respond, however, he may not have heard Juma's circuit either. I would suspect rather similar because both are single ended, fb amps with lateral fet output stages. There are differences due to the lower loop gain, however, because bipolars have far higher transconductance and this increase the feedback level. I would say that the lower the loop gain, the more natural sounding the amp generally becomes. Even so, comparisons are very difficult, since people like different things. I'm sorry I can't say more, but I can say that the FETzilla should be extremely easy to listen to, very resolving, and a little warm.
George, you can use one larger trafo for both modules without issue. This saves money and is practical. You will neeed to duplicate each secondary winding, so start and finish each have two wires to connect to corresponding power supplies on each module. (That is, one secondary winding to supply both positive power rails, left module and right module, and the other secondary winding supplying both negative power rails, left module and right module.) However, and again IME, this may lead to slightly less image stability, where you will have a less defined left right image. On most music, this won't be noticeable.
Cheers,
Hugh
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Hi Hugh,
Will you be providing a PDF documentation of all the recommended components, as well as testing procedure?
Eg: 1% Dale metal film resistors, Panasonic FC caps, WIMA MKP
This way the majority of the builders will have the exact same components used in the amp and can be built as closely as possible as the designer(s) intended.
Will you be providing a PDF documentation of all the recommended components, as well as testing procedure?
Eg: 1% Dale metal film resistors, Panasonic FC caps, WIMA MKP
This way the majority of the builders will have the exact same components used in the amp and can be built as closely as possible as the designer(s) intended.
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