First impression: Herron VTPH-2A phono preamp
rob67Your very welcome Rob, and thank you very much for the kind words. Glad you like it so much and how it sounds, you’ve said it like it is. Are you going to try the 12v Li-Ion rechargeable battery to power the Lightspeed with? It will give a good week of listening before a recharge is needed. https://www.ebay.com/itm/EU-DC-12V-6800mAh-Portable-Rechargeable-Li-ion-Battery-Pack-fr-CCTV-Cam-Mon... Cheers George |
I am of The opposite mindset of George, I wish amplifiers had less gain. It's easier for preamplifiers to not mess up the sound so I would rather establish the gain earlier on in the system and just have amplifiers providing the current when needed.I'll go one further than that, I wish also that there was no gain the amp just used for current, but all the gain needed being in the source (which it can be), with it's gain being adjustable for volume. Which funnily is a direct source to amp connection or via a passive. What ever the source has, use it all, and stop shunting it back to ground with the volume control, because you have too much gain down the line, eg: the preamp gain section and amp gain. Cheers George |
almarg Al rob67 just let me know that the Lightspeed's logarithmic volume controls are at 12 o'clock for normal loud listening levels on his system. And as you know 12 o;clock is not even half volume yet, it's 2pm on the Lightspeed. As you can see absolutely no need for any more active preamp gain and the noise it brings. He also said the Lightspeed wins out over his Audio Research REF-5se and older Pass X1. He's now getting a battery for the Lightspeed and will hopefully do an update here on that. Gain structure he has. Lyra Etna SL 0.25mV > Herron 64db > Lightspeed 0db > Gryphon Antillion 30db > Wilson Sasha 90db His Turntable https://i.pinimg.com/originals/c5/da/d3/c5dad306fea0f6cdda772d0ed07c2425.jpg Cheers George |
professorsvsu OP A ladder attenuator configuration (the best) https://ibb.co/kCLLKJ A 10k ladder has a max output impedance of 2.5k, and with the 30k of the 4B that's a 1:12 ratio, pity yours 25k if it's a ladder it will be 1:6 ratio, but saying that, it maybe fine as below you see that out of 30 audiophiles only two detected something below 1:10 We conducted 30 strong audiophile group listening, level matched using 1khz test cd at the speaker within 10th of a volt, then with music. Using an amp I made to be able to change the input impedance quickly, and my Lightspeed (a ladder) the group could not hear any difference from 1:100 ratio down to 1:10 ratio. A couple "thought" they heard something lower than 1:10, but it wasn't till 1:3 ratio that 50% thought they heard a difference. Cheers George |
What improvement is the VTPH-2A vs the VTPH-2? I don’t think there’s much from what I saw of the specs, the 2A is 100ohms lower in output impedance, (400 instead of 500), the rest seemed the same. 2: http://www.herronaudio.com/images/vtph2data.pdf 2A http://www.herronaudio.com/vtph2specs.html at the bottom Yep, 8db lower noise on the 2A Cheers George |
Hey, I have three times as much wattage than I need, I don’t use it. 99.9% of use don’t use our full wattage potential that we have on tap, idiots that do will need speaker repairs very quickly. So loud enough is loud enough, and there’s no penalty if you can’t clip your amp with the given signal, so long as you can reach the level you need, having the ability to go up to 11 doesn’t give you any sound quality advantage at all. Cheers George |
IMO, in most circumstances if the front end of a system cannot drive a power amp to full power the system has not been configured in an optimal manner.I hope you don’t mean it’s going to be more "dynamic" if it’s plenty loud enough for the user, but can’t clip the amplifier in theoretical terms, as some shonk’s here on Audiogon have tried to make out Cheers George |
Awesome! It’s a small world, as the saying goes.Yeah, I don’t know if you know this but Kim (who owns Deqx) was the co/inventor of the first Fairlight Synthesizer back in 1979. https://www.youtube.com/watch?v=iOlPCpSmhRM Here's a pic of a young Kim Ryrie https://www.mixonline.com/.image/t_share/MTUxNDIwMTI5OTI3MTc3NDQ2/509techof11gif.gif Cheers George |
For my preamp I used a DEQX HDP-5, which as you may be aware is produced by some of your fellow countrymen Down Under, and provides numerous DSP-based functions including improving speaker time coherence and room correction. To make that possible analog inputs are converted to digital Yes I know Kim and Al very well, they are 200mts down the road from me in Brookvale. So Al now I know it's not possible for you to go passive with the Herron, as you use the Deqx as the pre, your converting your vinyl to digital then doing room/speaker digital eq'ing and xover'ing to it, then bringing it back to analogue domain again. Cheers George |
scmThanks for that info. There you go Al, even with .24mV MC and 87db speakers plenty of volume on tap. And the ATI amp seems to be 1.8v sensitivity. Your calculations have a hicup somewhere. Cheers George |
scm So you had enough volume with the passive even though you had a very low 0.24mV MC cartiridge, you didn't have >100db horn speakers? also what was your amps gain or sensitivity? And the VP1 is the same gain and even higher output impedance. Cheers George |
Al, like I said before some of my customers with MC and 48db phono stages are having no problem, around 2pm on the VC, but then they have "normal" gain poweramps and speakers that are efficient. If you run one of say Nelson’s low gain F series amps or similar then yes I agree there could be gain issues, lets wait and see what Rob67 has to report he has a MC that is a $10kusd Lyra, and his amp and speakers are in the "normal" rage of things. BTW: For normal listening levels in your setup where is your vc positioned on your active pre and do you know it’s gain? Does it have a log pot? And what is the gain of your amp and efficiency of your speakers? Cheers George |
You’ve got the option of 69db of gain Al also have a look at the on line manual/specs. Also with average gain of amps at around 27db and speakers that are average around 88db you certainly will have enough volume range Maybe not with low gain amps as the NP Aleph’s and such, and low efficiency speakers such around 82db. As for the 2.5v output figure into 20kohm at 0.03% distortion this is far less than what a cartridge has as a distortion, they are closer to 1% so to me that doesn’t mean much. Well see what rob67 has to report re gain, as his Gryphon Antillion amp is around average at 1v sens and his Wilson Sasha speakers are around average at 90db As I said I have customers with tube phono stages that have lower gain around 48db and 1kohm output impedance they don’t have any issue with not enough volume. I make it a point of asking where the volume control is for normal/loud listening, and they say around 2pm which gives them plenty of range up or down. Many of my vinyl junkie customers are here on these forums, hopefully they will respond as I can’t remember who has what, as there are over 900 out there. Cheers George |
if he says that 20K is a bare minimum He’s quoting, like me saying 47k and 100k is even better is the figure for the Lightspeed to see, when in fact 25kohm is the min correct figure as measured and listened too by our 50 strong audio group, as that gives a 1:10 ratio as the max output impedance of a 10k volume control is 2.5k, were just taking in any unforeseen circumstances like weird cables etc. We’ll see when Rob67 reports on what he heard, as for now as I said before lesser phono stages are sounding great into this kind of load. Al do your ears a favour, ditch the dinosaur if you have the gain, and "not" listen to the noise floor of your preamps output gain stage, you’ll be amazed just how black the background of vinyl can sound if you utilise all the phono stage’s gain instead. He’s given you massive 64db or 69db of gain, use it, some poor saps only get 35db of gain with their phono stages and they have to listen to the preamps output gain stage’s noise. Cheers George |
Keith just emailed me, here’s what he said. "Hi George, As you can see no problems with bass rolloff as the cap is 7uf and he’s done the measurements flat to 10hz, into the same load as a 10kohm passive represents! My calculations with 7uf into 10kohm load are -3db at 2hz, perfect! All looks fine to me for it to be used with a passive preamp, as the gain is very high for this phono stage, so you may as well utilise it all, instead of knocking it back because of the gain in an active preamp, this way you’ll get a definite lower background noise level. Also Keith said the Distortion: Less than 0.03% at 2.45 volts RMS output at 1kHz at 20k Ohm, this also "to me" bodes well for passive preamp use. If you’ve got’em smoke em! to see how it sounds. We’ll see after this weekend what rob67 thinks of it with the Lightspeed as it mimics a 10kohm passive volume control. I’ve got other customers of mine with tube phono’s that aren’t spec’d as good as this for passive use, they say it’s the best they’ve heard their vinyl sound, once they got rid of the active preamp. Cheers George |
almarg I can see where your coming from Al, the 400ohm is fine, as you say if the output coupling cap is too small there would be some rolling off the bass too early with a 10kohm passive. I just did some calculations and if that coupling cap is 1uf or more all is fine. Do you know how big it is maybe you have one? I have sent an email and asked Keith I will post it up when he reply's. And if it is less than 1uf there's no trouble or much cost making it bigger, and at the same time a better quality one. And the gain can be either: From Herron Gain MC Mode (2 X 12AX7, 3 X 12AT7) 64 dB (4 X 12AX7, 1 X 12AT7) 69 dB Cheers George |
Yes do try it, because with all that gain the Herron has, you may as well use it all and not have more noise from active pre’s that you’d have to turn right down to throw away the gain of the Herron. Do you know what the impedance of your Goldpoint is?? ( 5K, 10K, 25K, 50K, 100K, and 250K.) hopefully it’s the 10k one as this will suit nearly all situations, as this is important to get a good impedance with your amps input impedance if you know that too? I believe you have the Bryston 4B cube which is 33kohm rca that’s fine if the Goldpoint is the 10k one. Cheers George |
professorsvsu rob67 has one of these Herron’s phono stages, and because it has nice low 400ohm output impedance for a tube and high (69db) of gain, he probably doesn’t need any more gain from an active preamp, so he’ll be trying it out with his new Lightspeed Attenuator (should be far lower noise this way) he should have it this weekend which will be driving into his Gryphon Antilleon Signature poweramp driving his Wilson Sasha’s, I’ll ask him to comment on the sound here for you once he’s had a good listen.. Cheers George |
Yeah I saw that with the 4B cube it has two switchable gain settings. Here’s something you may like to know, "if" this gain changing is done where most are done, the same way I used to do my tube or solid state amps I built, via changing the nfb (negative feedback ratio). Then you may like to know that a higher gain setting is a lower feedback ratio, which "can" give the 4b a slightly more tube sound with a little less damping factor and maybe more 2hd. Cheers George |
