I was tempted too...
And, what a surprice! The little golden amp really made bass! On speakers with difficult impedance-curves...!
Exept for max output, it easily trashed a Dynaco ST-70, and a couple other cheap chinese EL34! amps for sound-quality.
However, I will admit having changed the (4x) 0,1uF coupling caps to MKP-type, and swapped the vol-pot. for a cheap "mini-attenuator" (~$20+ from epay)
Arne K
And, what a surprice! The little golden amp really made bass! On speakers with difficult impedance-curves...!
Exept for max output, it easily trashed a Dynaco ST-70, and a couple other cheap chinese EL34! amps for sound-quality.
However, I will admit having changed the (4x) 0,1uF coupling caps to MKP-type, and swapped the vol-pot. for a cheap "mini-attenuator" (~$20+ from epay)
Arne K
Initial Review of Suppo Golden Voice EL84 Amplifier
This is a rather lengthy review of the Suppo Audio Golden Voice EL84 amplifier, but if you are interested in a basic, affordable vacuum tube amplifier requiring no bias adjustments and plenty of mod potential, you might be interested in reading this...
Soundstage recreation - The image is very focused and the soundstage is large in all three dimensions (height, width, and depth). With the extended bass response of the B&W DM603 loudspeakers (90dB sensitivity), the soundstage and imaging grew tremendously in size. With Charles Munch and the Boston Symphony Orchestra playing Ravel's "Le Valse" and "Rapsodie Espagnole" (RCA Living Stereo SACD/CD Hybrid), the soundstage expands on crescendos and recedes nicely on quieter passages. With both speaker sets and more so with the Fostex monitors, the sound extended beyond the far edges of the speakers. On Laurie Anderson's "Mister Heartbreak" (Warner) and Sade's "Love Deluxe" (Sony), there are some spacey sounding tracks that have a holographic presentation. As much as I love my Class D amp, tube amps like the Golden Voice win out here.
Clarity, transparency, resolution - I am able to pick up some details I hadn't heard before, especially on the Bill Evans Trio "Waltz for Debbie" (Riverside). On my Fostex monitors, I could hear Scott Lefaro sliding his fingers on the bass strings in a way I've never heard with the other two amps. This is a transparent amp with a very clear, cohesive sound. In fact, it seems to be more transparent than the more expensive Onix SP3 amp.
Airy, spacious, openess - I hear more spatial cues, especially on well recorded orchestral performances on the RCA Living Stereo and Mercury Living Presence SACD/CD hybrid discs. The concert halls on the orchestral CDs really come through well, especially the natural hall reverb of bass drums, tympanis and brass instruments. I was impressed with the clarity and air with the B&W's.
Bass Response - with my Fostex FX120 speakers, these monitors aren't the last word on bass response, but the bass is weighty and quick, not slow or bloomy. The upright bass' wooden body comes through on good recordings, along with the finger work on the strings. I was very surprised at how this amp produces more bass and mid-bass energy than the more powerful Virtue Two. With the fullrange floorstanding B&W's, the bass response adds greater weight to the notes and peaks. On the Michael Jackson "This Is It" companion CD (Sony), most of the tracks were remastered and the bass lines on "Wanna Be Startin' Somethin'" and "Smooth Criminal" were clean and punchy with proper timing.
Transient response, attack - Pace, Rhythm and Timing (PRaT) is really good with this little amp. I often find myself tapping my feet and feeling more involved with the performance than listening to the system. I always thought that the Virtue and other Tripath-powered amps were good at this and had the edge on tube amps, but the Golden Voice can keep up easily. Tympani strikes, piano key strikes and the weighty blast on trumpets are reproduced very nicely with full notes-attack and decay. On Santana's "Caravanserai" (Columbia), there are a number of tracks with Latin percussion and great electric guitar rifts. With that jazz-rock fusion album, the Golden Voice tracked well, albeit at moderate loudness. Only with heavy rock does the 8 watt output give out. They're by no means great recordings in the audiophile sense, but the live performances of "Baba O'Reilly" and "Won't Get Fooled Again" on The Who's "The Kids Are Alright" (MCA) have a lot of rock and roll energy with Keith Moon on drums and John Entwistle on bass, but the Golden Voice just couldn't move the B&W's drivers to convincing volumes or slam. Perhaps a more efficient Klipsch or line array might do better with the Golden Voice.
Smoothness - After some burn-in and adequate warming up, this amp does not have a hint of graininess. It is very liquid just like my other amps, and the amp's smoothness remains intact during peaks and complex passages. The swings in tempo and intensity really come through with surprisingly great ease. What this amp won't do with decent speakers is gloss-over bad recordings. If there are recordings with tape noise, sibilance and distortion, it will come through. I wouldn't characterize the sound of this tube amp as euphonic. However, if the recording is really good like Chanticleer's "How Sweet the Sound" (Warner) this amp's smooth delivery is rewarding. Vocal harmony is very nice with this CD.
Tone - This amp has a very natural presentation of tone, especially on piano. It also comes through clearly on strings, woodwinds and brass too. As long as the recording quality is good, instruments have a full tone that adds to a more realistic presentation. Tonal textures come through clearly and this helps convey the emotion of the performance. On Ellis and Branford Marsalis' "Loved Ones" (Columbia), the piano and sax are reproduced with wonderful realism in tone and weight.
Construction, build quality - Unfortunately, this is where this amp falls short. For the amount I paid for the amp, I shouldn't expect much, but the top plate where all the tubes and transformers are mounted does sag from the weight. I brought the amp to friend's home for auditioning, and he thought the amp looked good, and didn't notice the sagging top plate until I brought it to his attention. Joe of Suppo aid that they will start using a thicker Aluminum plate to eliminate sagging.
Volume pot: As I mentioned before, the volume pot on my unit was defective with the right channel noticeably stronger than the left channel. After replacing the volume pot, the sound was fantastic and most of my review is based on the Suppo amp with the Panasonic EVJ volume pot installed. I will probably replace the Panasonic EVJ pot with a compact SMD stepped attenuator that I've bought from eBay seller Gigawork. I already replaced my volume knob with a nicer solid, machined Aluminum knob I bought through eBay.
Fuse and power switch: Others have chimed in that a fuse and DPDT switch should be installed and Suppo will start selling units with this. I will replace the IEC inlet with one that is bolted in rather than snapped in and held firmly in place with hot melt adhesive. I'll also install a DPDT switch and fuse holder too.
PCB and transformers: The PCB and transformers seem to be of good quality as far as I can hear and see. I'm trying to decide if I want to replace the well regarded Panasonic ECQP Polypropylene film coupling caps with better caps like AmpOhm Tin foil/film and oil caps or Auricap metallized Polypropylene film caps. I am open to any suggestions. I might just leave them alone, because the amp sounds pretty good as-is with the Panasonic caps.
Wiring and connectors: I will replace most of the wiring with Teflon-insulated solid core Silver and Teflon-insulated stranded Copper wiring. I've ordered some new binding posts and RCA connectors as well--nothing exotic--but better than the stock parts.
In Closing...
It should be obvious that I am impressed with this little amp--defective volume pot, sagging top plate and all. I used think that the <$100 T-amps that have flooded the budget hifi market were the best deals for bang-for-the-buck sound, but I believe this one might be one of the better offerings out there, especially for those who have never considered a tube amp. It's definitely a great deal if you can sling solder and modify and upgrade the amp yourself, because this little amp has some potential to be a lot better. In fact, I will post in the future of improvements I plan to make to this amp. It will never compete on the level of many great and significantly more expensive amps I have heard at the Burning Amp Festivals or other gatherings, but it could hold its own against the budget T-amps and mass mid-fi solid state amps selling for the same or significantly more money. If you love listening to a range of music like I do and you have speakers with reasonable efficiency and impedance, you should consider this amp.
This is a rather lengthy review of the Suppo Audio Golden Voice EL84 amplifier, but if you are interested in a basic, affordable vacuum tube amplifier requiring no bias adjustments and plenty of mod potential, you might be interested in reading this...
- Source: Modified Playstation One, Model SCPH-1001
- Interconnects: Onix Blue, shielded OFC cable with WBT-type locking connectors
- Speaker Cables: DIY Walmart White Lightning Moonshine speaker cables with Multi-Contact banana connectors
- Speakers: Fostex FX120 single drivers installed in small vintage Jordan-Watts bass reflex enclosures, B&W DM603 Series 1 floorstanding loudspeakers
- Power Cables, Zu Birth and Zu Bok (amps), and PS Audio Xstream Power Punch C7 (Playstation)
- Amps for comparison: Onix (a.k.a. Melody Valve) SP3 5881/6L6GC-based integrated vacuum tube amplifier, Virtue Audio Two Class D Tripath-powered integrated amplifier
Soundstage recreation - The image is very focused and the soundstage is large in all three dimensions (height, width, and depth). With the extended bass response of the B&W DM603 loudspeakers (90dB sensitivity), the soundstage and imaging grew tremendously in size. With Charles Munch and the Boston Symphony Orchestra playing Ravel's "Le Valse" and "Rapsodie Espagnole" (RCA Living Stereo SACD/CD Hybrid), the soundstage expands on crescendos and recedes nicely on quieter passages. With both speaker sets and more so with the Fostex monitors, the sound extended beyond the far edges of the speakers. On Laurie Anderson's "Mister Heartbreak" (Warner) and Sade's "Love Deluxe" (Sony), there are some spacey sounding tracks that have a holographic presentation. As much as I love my Class D amp, tube amps like the Golden Voice win out here.
Clarity, transparency, resolution - I am able to pick up some details I hadn't heard before, especially on the Bill Evans Trio "Waltz for Debbie" (Riverside). On my Fostex monitors, I could hear Scott Lefaro sliding his fingers on the bass strings in a way I've never heard with the other two amps. This is a transparent amp with a very clear, cohesive sound. In fact, it seems to be more transparent than the more expensive Onix SP3 amp.
Airy, spacious, openess - I hear more spatial cues, especially on well recorded orchestral performances on the RCA Living Stereo and Mercury Living Presence SACD/CD hybrid discs. The concert halls on the orchestral CDs really come through well, especially the natural hall reverb of bass drums, tympanis and brass instruments. I was impressed with the clarity and air with the B&W's.
Bass Response - with my Fostex FX120 speakers, these monitors aren't the last word on bass response, but the bass is weighty and quick, not slow or bloomy. The upright bass' wooden body comes through on good recordings, along with the finger work on the strings. I was very surprised at how this amp produces more bass and mid-bass energy than the more powerful Virtue Two. With the fullrange floorstanding B&W's, the bass response adds greater weight to the notes and peaks. On the Michael Jackson "This Is It" companion CD (Sony), most of the tracks were remastered and the bass lines on "Wanna Be Startin' Somethin'" and "Smooth Criminal" were clean and punchy with proper timing.
Transient response, attack - Pace, Rhythm and Timing (PRaT) is really good with this little amp. I often find myself tapping my feet and feeling more involved with the performance than listening to the system. I always thought that the Virtue and other Tripath-powered amps were good at this and had the edge on tube amps, but the Golden Voice can keep up easily. Tympani strikes, piano key strikes and the weighty blast on trumpets are reproduced very nicely with full notes-attack and decay. On Santana's "Caravanserai" (Columbia), there are a number of tracks with Latin percussion and great electric guitar rifts. With that jazz-rock fusion album, the Golden Voice tracked well, albeit at moderate loudness. Only with heavy rock does the 8 watt output give out. They're by no means great recordings in the audiophile sense, but the live performances of "Baba O'Reilly" and "Won't Get Fooled Again" on The Who's "The Kids Are Alright" (MCA) have a lot of rock and roll energy with Keith Moon on drums and John Entwistle on bass, but the Golden Voice just couldn't move the B&W's drivers to convincing volumes or slam. Perhaps a more efficient Klipsch or line array might do better with the Golden Voice.
Smoothness - After some burn-in and adequate warming up, this amp does not have a hint of graininess. It is very liquid just like my other amps, and the amp's smoothness remains intact during peaks and complex passages. The swings in tempo and intensity really come through with surprisingly great ease. What this amp won't do with decent speakers is gloss-over bad recordings. If there are recordings with tape noise, sibilance and distortion, it will come through. I wouldn't characterize the sound of this tube amp as euphonic. However, if the recording is really good like Chanticleer's "How Sweet the Sound" (Warner) this amp's smooth delivery is rewarding. Vocal harmony is very nice with this CD.
Tone - This amp has a very natural presentation of tone, especially on piano. It also comes through clearly on strings, woodwinds and brass too. As long as the recording quality is good, instruments have a full tone that adds to a more realistic presentation. Tonal textures come through clearly and this helps convey the emotion of the performance. On Ellis and Branford Marsalis' "Loved Ones" (Columbia), the piano and sax are reproduced with wonderful realism in tone and weight.
Construction, build quality - Unfortunately, this is where this amp falls short. For the amount I paid for the amp, I shouldn't expect much, but the top plate where all the tubes and transformers are mounted does sag from the weight. I brought the amp to friend's home for auditioning, and he thought the amp looked good, and didn't notice the sagging top plate until I brought it to his attention. Joe of Suppo aid that they will start using a thicker Aluminum plate to eliminate sagging.
Volume pot: As I mentioned before, the volume pot on my unit was defective with the right channel noticeably stronger than the left channel. After replacing the volume pot, the sound was fantastic and most of my review is based on the Suppo amp with the Panasonic EVJ volume pot installed. I will probably replace the Panasonic EVJ pot with a compact SMD stepped attenuator that I've bought from eBay seller Gigawork. I already replaced my volume knob with a nicer solid, machined Aluminum knob I bought through eBay.
Fuse and power switch: Others have chimed in that a fuse and DPDT switch should be installed and Suppo will start selling units with this. I will replace the IEC inlet with one that is bolted in rather than snapped in and held firmly in place with hot melt adhesive. I'll also install a DPDT switch and fuse holder too.
PCB and transformers: The PCB and transformers seem to be of good quality as far as I can hear and see. I'm trying to decide if I want to replace the well regarded Panasonic ECQP Polypropylene film coupling caps with better caps like AmpOhm Tin foil/film and oil caps or Auricap metallized Polypropylene film caps. I am open to any suggestions. I might just leave them alone, because the amp sounds pretty good as-is with the Panasonic caps.
Wiring and connectors: I will replace most of the wiring with Teflon-insulated solid core Silver and Teflon-insulated stranded Copper wiring. I've ordered some new binding posts and RCA connectors as well--nothing exotic--but better than the stock parts.
In Closing...
It should be obvious that I am impressed with this little amp--defective volume pot, sagging top plate and all. I used think that the <$100 T-amps that have flooded the budget hifi market were the best deals for bang-for-the-buck sound, but I believe this one might be one of the better offerings out there, especially for those who have never considered a tube amp. It's definitely a great deal if you can sling solder and modify and upgrade the amp yourself, because this little amp has some potential to be a lot better. In fact, I will post in the future of improvements I plan to make to this amp. It will never compete on the level of many great and significantly more expensive amps I have heard at the Burning Amp Festivals or other gatherings, but it could hold its own against the budget T-amps and mass mid-fi solid state amps selling for the same or significantly more money. If you love listening to a range of music like I do and you have speakers with reasonable efficiency and impedance, you should consider this amp.
I received my Suppo amp a few days ago and so far its nice. I actually was more impressed with the build quality than the sound. Mine arrived with a nice solid chassis without any sag.. I have NOT change pots, tubes caps or anything for that matter - still stock. No issues with balance with mine either.
But it does sound nice on my B&W DM220i's. I think I slightly prefer my Magnavox 6V6/6EU7/6AC4 PP amp in overall clarity and accuracy with my JFET BOZ preamp in front... could be the power difference (8 wpc vs 15 wpc) ...I will be continuing to listen for a few more days before handing it to another friend that has some serious gear (Rowland, Mark Levinson, Revel, etc) who always gives me critiques on my DIY equipment.
But it does sound nice on my B&W DM220i's. I think I slightly prefer my Magnavox 6V6/6EU7/6AC4 PP amp in overall clarity and accuracy with my JFET BOZ preamp in front... could be the power difference (8 wpc vs 15 wpc) ...I will be continuing to listen for a few more days before handing it to another friend that has some serious gear (Rowland, Mark Levinson, Revel, etc) who always gives me critiques on my DIY equipment.
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The other day I received the Suppo EL84 AMP. The amp itself was really small, but quite heavy and quite solid. If I compare it to the LAAudio A-30 integrated amp, which is also very cheap, this Suppo amp is a lot more solid.
Unfortunately one of the tubes was punctured during transport so I put in a matched quad of Manley EL84M (Russian made, probably by Sovtek/Reflector). These tubes are normally used in the Manley Stinray integrated amp.
Source: Sony 820 QS CD-player with PDaniel NONOS DAC.
Interconnect: digital: IBM coax token ring cable, analog: Oehlbach NF1
Speakers: Focal Micro Utopia BE
Speaker wire: Twisted and woven silver in teflon
Other systems: Aleph 30 clone and Peter Daniels INT-1
After a couple of days with many hours of up-time the tubes settled in and the sound started to take shape. At first it was quite harsh and fatiguing. Right now the sound is very clean and the sound-stage is huge! Especially in recordings like Stacey Kents Ice Hotel the depth of the sound-stage much exceeds the representation from the INT-1. I hadn't heard this for a while. For this quality in sound and build this amp is an absolute bargain. The amp lacks definition in the lower region compared to the Aleph 30 and the INT-1, but the 3D sound-stage makes up for this easily. For pop music this amp may not be the best, but singer song writer this amp really “sings”. Another positive is the absolute quietness of the amp. These is just the faintest hum if I put my ear next to the speaker, but this fades away after an hour or so. Noise or hiss was never audible. Also power up and power down goes really gently. Quite different than the Zen amps.
The amp has still some distortion especially in female voices, but I suspect this may be a result of the NOS DAC that has a lot of 44kHz energy that may have some effect on THD of this amp or maybe still some break-in, since I only have the amp for a week. Unfortunately I have to wait till the Christmas holidays before I can do THD measurements to see where it comes from. On other sources it is less of a problem, but they are also less clear.
In a week or two/three I hopefully have performed those and bandwidth measurements which I will post here.
Finally, the top plate temperature becomes 56°C at ambient of 22°C. Quite an OK figure and certainly no problem.
Modifications that I am planning is replacing the power switch, adding an extra set of inputs, changing the input tubes, rewire to silver internal wire and change C2,C3,C14 and C15caps to paper in oil.
Thanks Joe for this excellent amp and the personal support you provide.
Unfortunately one of the tubes was punctured during transport so I put in a matched quad of Manley EL84M (Russian made, probably by Sovtek/Reflector). These tubes are normally used in the Manley Stinray integrated amp.
Source: Sony 820 QS CD-player with PDaniel NONOS DAC.
Interconnect: digital: IBM coax token ring cable, analog: Oehlbach NF1
Speakers: Focal Micro Utopia BE
Speaker wire: Twisted and woven silver in teflon
Other systems: Aleph 30 clone and Peter Daniels INT-1
After a couple of days with many hours of up-time the tubes settled in and the sound started to take shape. At first it was quite harsh and fatiguing. Right now the sound is very clean and the sound-stage is huge! Especially in recordings like Stacey Kents Ice Hotel the depth of the sound-stage much exceeds the representation from the INT-1. I hadn't heard this for a while. For this quality in sound and build this amp is an absolute bargain. The amp lacks definition in the lower region compared to the Aleph 30 and the INT-1, but the 3D sound-stage makes up for this easily. For pop music this amp may not be the best, but singer song writer this amp really “sings”. Another positive is the absolute quietness of the amp. These is just the faintest hum if I put my ear next to the speaker, but this fades away after an hour or so. Noise or hiss was never audible. Also power up and power down goes really gently. Quite different than the Zen amps.
The amp has still some distortion especially in female voices, but I suspect this may be a result of the NOS DAC that has a lot of 44kHz energy that may have some effect on THD of this amp or maybe still some break-in, since I only have the amp for a week. Unfortunately I have to wait till the Christmas holidays before I can do THD measurements to see where it comes from. On other sources it is less of a problem, but they are also less clear.
In a week or two/three I hopefully have performed those and bandwidth measurements which I will post here.
Finally, the top plate temperature becomes 56°C at ambient of 22°C. Quite an OK figure and certainly no problem.
Modifications that I am planning is replacing the power switch, adding an extra set of inputs, changing the input tubes, rewire to silver internal wire and change C2,C3,C14 and C15caps to paper in oil.
Thanks Joe for this excellent amp and the personal support you provide.
Attachments
Been listening to my two EL84 ams for about a week now. Yes, I bought two, one for modifying and one I will keep standard (for a while) for comparison. My system is finally to my liking. I have a oppo CD player modded so I can take the SACD out directly to my dac, and a shingaclone cd player. I primarily listen to my DIY AYAII dac with a nice 1541 single crown, and a pair of half-jimi chang speakers, with full range jordans (great speakers).... I have been listening to the same system with an aikido with JAN 6sn7s into a F4, for about a year now.
First impressions were very good, while I love the F4 and aikido combo, the tube amp sound was very nice to hear again. The first thing I noticed was no hum, nothing, I hate hum, so this was really positive. Also let me say that I am not a golden eared reviewer. I play no instrument and can't even hum a tune on key, at least that is thats my wife tell's me, I just like to build and listen to high quality stuff and I can tell the difference.
During the first few days of break-in, listening to everything from jazz, blues, a little rock, but mostly very good classical CDs, the EL84 sounded great. To be really critical on some tracks I did occasionally notice some grain and the music seemed a little veiled. I was surprised by how much solid bass I was getting from this small amp, it was certainly pushing my full range speakers to their limit. Over the past week, the grain and veil have slowly reduced.
I started with some tube rolling on the EL84 to be modded. First the Gold Lion tubes. Wow, is all I can say. Next some Russian 61NP-ev drivers. Double wow, even a tin ear could hear the difference. No veil, smooth as silk, very nice. Yesterday I compared the tube rolled version to the standard using all of the stereophile test CDs, while reading what I was suppose to hear. The sound stage, bass, and mids on all of the tracks were as described in the CD pamphlets.
I took my moddable unit apart after the listening test. Great build, I wish I could build chassis like that (I have the newer version in silver and black, not much hideous gold anodizing). So what's next: some distortion and FR measurements, swapping out the coupling caps with russian teflons, maybe a high voltage shunt or reg in the PS, and some new transformers???? I know what I will be doing over the christmas break
In closing, I think this is a very good amp and the best deal I have come across in a long time.
JimS
First impressions were very good, while I love the F4 and aikido combo, the tube amp sound was very nice to hear again. The first thing I noticed was no hum, nothing, I hate hum, so this was really positive. Also let me say that I am not a golden eared reviewer. I play no instrument and can't even hum a tune on key, at least that is thats my wife tell's me, I just like to build and listen to high quality stuff and I can tell the difference.
During the first few days of break-in, listening to everything from jazz, blues, a little rock, but mostly very good classical CDs, the EL84 sounded great. To be really critical on some tracks I did occasionally notice some grain and the music seemed a little veiled. I was surprised by how much solid bass I was getting from this small amp, it was certainly pushing my full range speakers to their limit. Over the past week, the grain and veil have slowly reduced.
I started with some tube rolling on the EL84 to be modded. First the Gold Lion tubes. Wow, is all I can say. Next some Russian 61NP-ev drivers. Double wow, even a tin ear could hear the difference. No veil, smooth as silk, very nice. Yesterday I compared the tube rolled version to the standard using all of the stereophile test CDs, while reading what I was suppose to hear. The sound stage, bass, and mids on all of the tracks were as described in the CD pamphlets.
I took my moddable unit apart after the listening test. Great build, I wish I could build chassis like that (I have the newer version in silver and black, not much hideous gold anodizing). So what's next: some distortion and FR measurements, swapping out the coupling caps with russian teflons, maybe a high voltage shunt or reg in the PS, and some new transformers???? I know what I will be doing over the christmas break
In closing, I think this is a very good amp and the best deal I have come across in a long time.
JimS
Update
I haven't modded my Suppo Golden Voice amp yet, but I did purchase a used pair of Klipsch Forte II speakers in decent shape at a great price. I have never owned a pair of Klipsch speakers before, because everytime I had heard them they weren't that impressive. They were usually paired with some awful mid-fi solid state receiver. Anyway, I wired up the Forte's with the Suppo and I have to say that the sound is very impressive. The Suppo is quick and it matches the dyanmic range of the Forte's very nicely.
I've read that many old Scott amp owners pair their amps with Klipsch speakers with great results. I agree with Jims that this is a good value for an EL84 amplifier. Tomorrow, a friend is bringing an EF86 linestage and a 9-pin Aikido linestage, and we're going to match it up with the Suppo as a power amp. Should be fun stuff and good music.
I haven't modded my Suppo Golden Voice amp yet, but I did purchase a used pair of Klipsch Forte II speakers in decent shape at a great price. I have never owned a pair of Klipsch speakers before, because everytime I had heard them they weren't that impressive. They were usually paired with some awful mid-fi solid state receiver. Anyway, I wired up the Forte's with the Suppo and I have to say that the sound is very impressive. The Suppo is quick and it matches the dyanmic range of the Forte's very nicely.
I've read that many old Scott amp owners pair their amps with Klipsch speakers with great results. I agree with Jims that this is a good value for an EL84 amplifier. Tomorrow, a friend is bringing an EF86 linestage and a 9-pin Aikido linestage, and we're going to match it up with the Suppo as a power amp. Should be fun stuff and good music.
Whatever the voltage rating of the original coupling capacitor is what you should probably be using.
Remember at power on the voltage across the coupling capacitor will approach the full B+ with solid state rectifiers. The answer to that question is that it is good design practice - in addition if a tube fails and the plate rises to B+ you don't want it to take out the capacitor and the next stage with it. (I have witnessed this event, it can be quite spectacular.)
As an aside there is a contention that the higher voltage films generally sound better than their lower voltage family members - why this should be is unclear to me, but in my limited experience it does sometimes seem to be true. (I generally use => 600V film caps in most cases anyway due to the voltages present in my circuit designs.)
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I had a chance to use the Suppo as a power amp today with an EF804S-based linestage amp, and I have to say that the performance was quite musical and enjoyable. This little amp has potential.
I am considering 0.1uF/630V Ampohm Tin Foil, Paper in Oil caps for the four coupling caps. C11 on the PCB is a 22uF/450V Chemi-con KXG electrolytic cap. Would the sound quality benefit from replacing this with something like a 20uF/700V Mundorf M-Tube film cap or even a film cap like a 22uF/400V Solens Fast Cap? I figure I could use standoffs and small board to form a lower deck within the chassis to mount these larger caps.
I am considering 0.1uF/630V Ampohm Tin Foil, Paper in Oil caps for the four coupling caps. C11 on the PCB is a 22uF/450V Chemi-con KXG electrolytic cap. Would the sound quality benefit from replacing this with something like a 20uF/700V Mundorf M-Tube film cap or even a film cap like a 22uF/400V Solens Fast Cap? I figure I could use standoffs and small board to form a lower deck within the chassis to mount these larger caps.
I have used different coupling caps before, they do make some differences to the sound reproduction, the changes are NOT earth shattering. Mundorf caps IMO are far too expensive.
If the power supply and anode caps are not good enough replace them with Panasonic caps and like you say add good quality bypass caps(0.1uF polypropylene good enough) in parallel. The combo will produce more dramatic result.
I have a cheap Chinese amp whose circuit I believe is inferior and I am preparing to change the circuit similar in topology to that use in your amp, simple and effective.
In the meantime enjoy your amp.
Thanks guys. I have a stock of K40Y-9 that I wanted to try, but these are only 200V.
By the way Joe, better use washers on the (good loocking) PCB standoffs or glue them. One of them was loose which resulted in a loose rattling nut.
Also, the OPTs nuts were loose, better glue them as well...
Thanks for this wonderful amp. This 100 Euro amp may not be the best match to my 4000 Euro Utopias, but they come pretty close. Quite amazing...
By the way Joe, better use washers on the (good loocking) PCB standoffs or glue them. One of them was loose which resulted in a loose rattling nut.
Also, the OPTs nuts were loose, better glue them as well...
Thanks for this wonderful amp. This 100 Euro amp may not be the best match to my 4000 Euro Utopias, but they come pretty close. Quite amazing...
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