Silent Screamer Posted October 10, 2018 Posted October 10, 2018 While I love my Halcro MC70 as a clean playing amplifier, it lacks musical soul. I'm using a active xover which takes care of numerous things like xover points, DAC, source control, etc. I recently heard that you can put a tube buffer in front of your amp to give it a nice warm tube amp sound. Kind of like a separated version of the hybrid Butler Audio amp I previously owned. My question is would it be difficult, or expensive to build a high quality 7 or 8 channel tube buffer to stick in front of the somewhat demure Class D amp?
Guest rmpfyf Posted October 10, 2018 Posted October 10, 2018 (edited) Depends on your definition of 'expensive'. I'd budget around $500-600 per stereo pair, so you project is a $2k or so job. That's from experience with a (very) good battery-powered buffer. I'd reach out to people here that build such things and ask nicely. You can tune ad infinitum by rolling tubes and caps here, and can probably save some $ by letting your bass channels be as they are. Edited October 10, 2018 by rmpfyf
doogie44 Posted October 10, 2018 Posted October 10, 2018 No, it wouldn't. Even the 'cheap' Yaquin buffers sound good to me--and I'm a valve lover. https://www.amazon.com/YAQIN-Stereo-Upgrade-Buffer-Processor/dp/B00DYHU0G0 The Musical Fidelity X-10 buffer qualifies here too. These come up from time to time on SNA. There are more expensive buffers: http://www.purityaudiodesign.com/300bbuffer.htm. I think around ($5K?). Pricey anyway. I should add that Mark at Retro-thermionic i Oz would likely be happy to make you a buffer to your specifications (from my conversations with him): http://retro-thermionic.blogspot.com/ Some people say that valve buffers don't do that much for the sound but I've found that when they are in place between the source and the amplifier they are potentially very pleasing. Cheap enough to experiment with Just my 2c worth 2
Ittaku Posted October 10, 2018 Posted October 10, 2018 (edited) You have 8 amplifiers? Or 4 stereo amps? Or some other arrangement? Yes you can build tube buffers (or buy them) but a tube buffer is 3/4 of a tube preamp in essence and to get a good quality preamp is expensive so you'll get what you pay for. There are cheap tube buffers, but I seriously doubt they'll be of reasonable quality to match what you're after. Aliexpress has kits starting from a measly $10 for two channel buffers, but they use some pretty nasty components and not the greatest selection of tube types. Something like this is probably on the fringe of acceptable for 2 channels, so you'd need 4 of them. I have zero experience with it, I'm just talking generically based on its design components. $140USD. https://www.aliexpress.com/item/YAQIN-SD-CD3-Stereo-Audio-6N8P-Signal-Sound-effect-Upgrade-hi-end-Tube-Buffer-Processor-for/32808725190.html Edited October 10, 2018 by Ittaku
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 27 minutes ago, Ittaku said: You have 8 amplifiers? Or 4 stereo amps? Or some other arrangement? To be honest I have lost track of how many amplifiers I own... But I am asking specifically for my active setup. I already have an all in one active pre (~$7k), so to buy another pre would be counterproductive. I am just looking for something simple I can put between the active xover outputs and the 7 channel Halcro inputs. If I went 4 way active I would need additional amplification unless I just didn't bother with a tube buffer on the bass.
Ittaku Posted October 10, 2018 Posted October 10, 2018 1 minute ago, Silent Screamer said: To be honest I have lost track of how many amplifiers I own... But I am asking specifically for my active setup. I already have an all in one active pre (~$7k), so to buy another pre would be counterproductive. I am just looking for something simple I can put between the active xover outputs and the 7 channel Halcro inputs. If I went 4 way active I would need additional amplification unless I just didn't bother with a tube buffer on the bass. That's fine, I just wasn't sure what the architecture of the Halcro was. So it's a 7 channel amp? Okay
michaelw Posted October 10, 2018 Posted October 10, 2018 sell the halcro and buy something with musical soul 1
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 2 minutes ago, michaelw said: sell the halcro and buy something with musical soul I would be in the neighbourhood of something like 4 stereo McIntosh's which I certainly don't have the money for these days. The Halcro is a great resolving amp it just lacks soul, it's a bit too clinical. If I could throw $1k-$2k at a buffer and get valve like sound, I think it would be well worth considering.
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 9 minutes ago, Ittaku said: That's fine, I just wasn't sure what the architecture of the Halcro was. So it's a 7 channel amp? Okay https://hometheaterreview.com/halcro-mc70-seven-channel-amplifier-reviewed/
aussievintage Posted October 10, 2018 Posted October 10, 2018 I would caution that a tube buffer might do less than you expect in moving your amp towards that "tube sound". Also, I am not a fan of many cheap small tube designs that run the tubes at starved plate voltages, and to buy 'decent' equipment just to try it out might prove expensive.
andyr Posted October 10, 2018 Posted October 10, 2018 1 hour ago, Silent Screamer said: My question is would it be difficult, or expensive to build a high quality 7 or 8 channel tube buffer to stick in front of the somewhat demure Class D amp? Not at all - that's what I've done. (Although I only use a tube buffer on 4 of my 8 amplification channels - the mids & ribbons. Subs & bass drivers get fed straight from the miniDSP.) Contact Hugh Dean … @AKSA. You'll have to build them - alternatively, he can supply the PCBs and the parts, and I can build them for you. 34 minutes ago, doogie44 said: Some people say that valve buffers don't do that much for the sound but I've found that when they are in place between the source and the amplifier they are potentially very pleasing. Cheap enough to experiment with Just my 2c worth Absolutely agree, d44. Hugh Dean's GK-1 and GK-2 preamps had a unity gain valve output buffer after the ss gain stage - which made the sound of mids and ribbons in my 3-way active system more attractive (compared to using the ss output to drive them). So when I removed the preamp from my system and fed the signal straight into the digital input of my miniDSP … I had to build an 8-channel volume control to go between the miniDSP unit and 8 monoblocs. Because of my experience with the GK-1 & GK-2, I included 4 channels of Hugh Dean's "TLP" tube buffer for the mids & ribbons, in the same case as the 8-channel volume control. Andy
andyr Posted October 10, 2018 Posted October 10, 2018 15 minutes ago, Silent Screamer said: I am just looking for something simple I can put between the active xover outputs and the 7 channel Halcro inputs. If I went 4 way active I would need additional amplification unless I just didn't bother with a tube buffer on the bass. I suggest you wouldn't want to put a tube buffer on the bass - as it will soften the leading edge of bass transients, slightly. Andy
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 4 minutes ago, andyr said: So when I removed the preamp from my system and fed the signal straight into the digital input of my miniDSP … I had to build an 8-channel volume control to go between the miniDSP unit and 8 monoblocs. Because of my experience with the GK-1 & GK-2, I included 4 channels of Hugh Dean's "TLP" tube buffer for the mids & ribbons, in the same case as the 8-channel volume control. Andy The GroundSound DCN28 fortunately has attenuation in both the digital and analog domains for each of the 8 channels, So I only really need to consider the buffer. I was only thinking 7 channel buffer in case I used the Halcro for the passive home theatre speakers and wanted to soften them. I am partial to the idea of doing only ribbons and mids like you. Cash flow isn't what it once was. Funny how buying a property cash will do that.
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 1 hour ago, rmpfyf said: Depends on your definition of 'expensive'. I'd budget around $500-600 per stereo pair, so you project is a $2k or so job. That's from experience with a (very) good battery-powered buffer. I'd reach out to people here that build such things and ask nicely. You can tune ad infinitum by rolling tubes and caps here, and can probably save some $ by letting your bass channels be as they are. Seems to be the consensus, only worry about the top end and let the bass fend for itself.
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 35 minutes ago, aussievintage said: I would caution that a tube buffer might do less than you expect in moving your amp towards that "tube sound". Also, I am not a fan of many cheap small tube designs that run the tubes at starved plate voltages, and to buy 'decent' equipment just to try it out might prove expensive. Would be done properly or not at all. I am not one for half doing things.
Guest rmpfyf Posted October 10, 2018 Posted October 10, 2018 Some really good suggestions here - 1 hour ago, doogie44 said: I should add that Mark at Retro-thermionic i Oz would likely be happy to make you a buffer to your specifications (from my conversations with him): http://retro-thermionic.blogspot.com/ 35 minutes ago, andyr said: Contact Hugh Dean … @AKSA. You'll have to build them - alternatively, he can supply the PCBs and the parts, and I can build them for you. There are also others depending on their availability. Try the usual boutique amp builders. Consider going battery-powered. The best I owned was a Dodd buffer (plenty of reviews online). Assembled with no switching and decent caps it was around $500 (there were more elaborate versions with remote controls and whatnot, though the basic version wasn't expensive at all). The kits were even less, about half that. Unfortunately Gary Dodd is no longer with us (and he potted a bunch of the circuit - nor has anyone wanted to disassemble something that sounds that good), though putting together a similar product shouldn't be hard for capable hands. Did wonders for my early-generation icepower amps.
andyr Posted October 10, 2018 Posted October 10, 2018 58 minutes ago, Silent Screamer said: The GroundSound DCN28 fortunately has attenuation in both the digital and analog domains for each of the 8 channels, So I only really need to consider the buffer. NP - I only mentioned the volume control bcoz that was in the context of my system. The two parts are independent (the tube buffer from Melbourne ... the volume control from Holland ). 58 minutes ago, Silent Screamer said: I was only thinking 7 channel buffer in case I used the Halcro for the passive home theatre speakers and wanted to soften them. I am partial to the idea of doing only ribbons and mids like you. Cash flow isn't what it once was. Funny how buying a property cash will do that. Leaving bass out will improve the result, IME. Hugh's TLP drives 2 channels from the 1 tube. So for mids & tweeters, you would need 2 kits. Andy
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 24 minutes ago, rmpfyf said: Consider going battery-powered. The best I owned was a Dodd buffer (plenty of reviews online). Assembled with no switching and decent caps it was around $500 (there were more elaborate versions with remote controls and whatnot, though the basic version wasn't expensive at all). The kits were even less, about half that. Unfortunately Gary Dodd is no longer with us (and he potted a bunch of the circuit - nor has anyone wanted to disassemble something that sounds that good), though putting together a similar product shouldn't be hard for capable hands. Did wonders for my early-generation icepower amps. I did read about battery power a while ago making significant sonic difference in terms of noise. I think if I was to have something custom made I would opt for battery power and true balanced line in and out (since both sides are balanced). There doesn't seem to be a monumental amount of electronics in the Dodd buffer.
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 Just now, andyr said: NP - I only mentioned the volume control bcoz that was in the context of my system. The two parts are independent (the tube buffer from Melbourne ... the volume control from Holland ). Leaving bass out will improve the result, IME. Hugh's TLP drives 2 channels from the 1 tube. So for mids & tweeters, you would need 2 kits. Andy I couldn't see a kit for this on his website.
andyr Posted October 10, 2018 Posted October 10, 2018 Just now, Silent Screamer said: I couldn't see a kit for this on his website. No, SS - bcoz: it's an old product, and Hugh is terribly slack at the website side of his bizniz. But his email address is on the website. Just FYI, here's a pic of my 2 TLP buffers in their enclosure (with the 8-channel, digitally-controlled, analogue volume controller). The 2 non-toroids on the left are the transformers which power the tube buffers (one per PCB): On the right, you might pick up that there are 4x quite large 1uF black caps lying horizontal on the case bottom panel. These are not the standard output caps that Hugh supplies ... I go for expensive, better-sounding ones ... which cost many times more than the buffers themselves! Interestingly enough - given rmpfyf's comment about battery-powered tube buffers - I get absolutely no hum and hiss at the drivers with these mains-powered tube buffers. Andy 1
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 (edited) 1 hour ago, andyr said: No, SS - bcoz: it's an old product, and Hugh is terribly slack at the website side of his bizniz. But his email address is on the website. Just FYI, here's a pic of my 2 TLP buffers in their enclosure (with the 8-channel, digitally-controlled, analogue volume controller). The 2 non-toroids on the left are the transformers which power the tube buffers (one per PCB): On the right, you might pick up that there are 4x quite large 1uF black caps lying horizontal on the case bottom panel. These are not the standard output caps that Hugh supplies ... I go for expensive, better-sounding ones ... which cost many times more than the buffers themselves! Interestingly enough - given rmpfyf's comment about battery-powered tube buffers - I get absolutely no hum and hiss at the drivers with these mains-powered tube buffers. Andy I would only want to use quality components and anything less wouldn't do, so I'm not sure what he is offering off the shelf would be good enough if you had to upgrade caps. I could always use a quality external mains powered 12v DC PSU, and if it wasn't up to scratch replace it with a battery DC power supply. Edited October 10, 2018 by Silent Screamer
andyr Posted October 10, 2018 Posted October 10, 2018 14 minutes ago, Silent Screamer said: I would only want to use quality components and anything less wouldn't do, so I'm not sure what he is offering off the shelf would be good enough if you had to upgrade caps. He uses components of the same quality that go into most commercial components, SS. AIUI, the sell to buy ratio for electronics is 5:1 - so, immediately, if anyone uses the Jupiter or SoniCap Platinum caps that I use in my gear ... the sale price goes up by $1500! With a kit, you can take what the seller offers and then add to that, if your pocket allows it. 14 minutes ago, Silent Screamer said: I could always use a quality external mains powered 12v DC PSU, and if it wasn't up to scratch replace it with a battery DC power supply. Tubes have high voltages - which is not really compatible with a 12v supply. I think the main output from the trannies Hugh supplies is 225v (there's also a 6v heater supply). But each to their own. Andy
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 (edited) 41 minutes ago, andyr said: He uses components of the same quality that go into most commercial components, SS. AIUI, the sell to buy ratio for electronics is 5:1 - so, immediately, if anyone uses the Jupiter or SoniCap Platinum caps that I use in my gear ... the sale price goes up by $1500! With a kit, you can take what the seller offers and then add to that, if your pocket allows it. Tubes have high voltages - which is not really compatible with a 12v supply. I think the main output from the trannies Hugh supplies is 225v (there's also a 6v heater supply). But each to their own. Andy Ok so if they need such high voltage how is it the Dodd buffer powered by 12v? At times $1500 will be neither here nor there (depending on how I feel on the day) Edited October 10, 2018 by Silent Screamer
Silent Screamer Posted October 10, 2018 Author Posted October 10, 2018 https://jupitercondenser.com/product-category/capacitors/ Those prices are up there but if appreciable gain is to be had... I wouldn't rule them out.
Ittaku Posted October 10, 2018 Posted October 10, 2018 1 hour ago, Silent Screamer said: I'm not sure what he is offering off the shelf would be good enough if you had to upgrade caps. Don't be so sure. You can still have very high quality caps without getting remotely close to the most expensive ones. A 1uF V-Cap CuTF cap costs $1000 each for example... 1
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