Hi Marty, Rlawry, thanks for your prompt reply.
There's something I don't understand, I checked that computer and looks like the optimum gain for my cart is 57db, my hovland phono stage has a total gain of 63db (46 of the phono + 17 of the built-in SUT), besides hovland states that it would overload above 0.9mv.
The gain of the line stage is 14db, so that could be the problem, but I have no problem with cd either, the volume is where I want.
Rlawry, maybe I should follow your suggestion and go for a solid state outboard phono stage like the Einstein, I can't imagine a tubed one with a gain higher than 63db.
I was just hoping that a cart in the 0.6/0.8 mv range would do the trick, but based on your comments that would not be the case.
Thanks again,
Marco |
Hi Hdm, the Hovland MC stage has a fixed impedance loading of approximately 530 ohm due to the built-in step-up transformers, as per instruction manual, with a "provision for reduced loading" by inserting resistors inside, but being the Colibri recommended load 500 ohm I thought that wouldn't be an issue.
Anyway, as I said before, I have no complaints for the sound quality, just for the quantity, I even thought to have Van den Hul increase the output, or trade in for the 0.65mv one, but I'm not sure that would fix the problem.
Do you think that reducing impedance loading would somehow increase the output level? I'm not much into tech stuff, I thought that would just affect tonality and/or frequency response. |
Hi Viridian, whoa, the SUT NOT in the circuit? That doesn't sound good!!!
I just opened the Hovland, the input phonos on the rear panel are directly plugged into a metal box with a writing that says "HOVLAND MC7 high gain phono stage", from there a cable goes into the circuit board that has the tubes for the phono stage, maybe that box is empty and i was charged for the SUTs anyway. Well, I guess if such a thing can happen, it would happen here to me. It's definitely time for that e-mail to Hovland, thanks for the suggestion, I'll report back asap. |
Rlawry, thank you, I think I understand your point, but I have to do some more homework to fully grasp the overall gain concept.
I now realize anyway, that I didn't previously make clear that the total gain of the unit is 77 dB, phono 63 dB, line 14 dB, as you can see in the Hovland web site http://www.hovlandcompany.com/products/electronics/hp100/specs.html.
That probably doesn't change the substance, and I agree that increasing gain would be a good solution, I'm now waiting for a reply from Hovland.
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Rlawry, that formula made me think a lot, for example, based on that, if the SUTs were out of the circuit the total gain would be 60 dB (77-17), and the max preamp output 0.45 volts, so am I correct in ruling out this option?
I don't know the gain of my power amps, but I know that, in my room with my system, when I use the CD I'm happy with the volume at 12 o'clock. Now, this CD has an output of 2 volts, the line stage has 14 dB gain, that means according to the formula a max output from preamp of about 10 volts. Let's assume that, to make me happy, I need 3 volts out of the preamp, and that happens when the volume knob hits 12 o'clock in CD replay, it would make sense that, to get the same 3 volts in LP replay, I need to hit 3 o'clock, in the noisy area, being the max output from phono 3.2 volts as per your calculation.
Bottom line, to bring the voume back to 12 o'clock with LPs, I think I need to increase the voltage gain of the phono stage, just as you said, and to do so I only see 2 options:
1-Outboard phono stage with higher gain as you suggested, is your Rhea noisy @ 75 dB?
2-Cart with higher output level, a 0.6 mv one would give a max output of about 4.3 volts, would those be enough to bring the volume back a few clicks down?
Hmmm, decisions, decisions, life is hard... |
Hi guys, thanks for all the inputs, I'm really learning a lot from all of you. Yesterday evening I got a phone call from Alex Crespi, VP Hovland company (WOW, he called me overseas, we're not used to that kind of customer care here), he very patiently explained to me that the 14 dB of gain of the line stage are for the most part located in the last part of the volume run (forgive my english, I hope you get what I mean) to give a better control, so it's not uncommon to have to work around 3 o'clock position. Besides, it could very well be that the 0.45 mv spec'd by VdH @ 5.7 cm/sec, are on the low side due to this slightly higher speed. He also said that the tube rush can be an issue at those volumes,I'm not the first to report it, and based on his experience, a cart output level in the 0.6/0.8 mv range should almost match the volume with CD. Now, I would like to point out, as I did in my original post, that this tube rush is not unbearable, I was just wondering how's life without any. Looks like, to find out I have to either change my beloved Colibri (Clearaudio anyone?) or go SS (hugh), or maybe the low noise tubes mentioned by Rlawry could do...
Life's getting harder, please keep the inputs coming guys, I really appreciate it.
Cheers,
Marco
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Hi Viridian, yes I thought about that, looks like I cannot contact VdH directly as I did with Hovland, the way to go is through the italian importer, I can send the cart back for "retuning" and in the meantime submit this request, it's gonna take a while, I'll let you know.
Hi Gregm, I'm sorry I also don't understand, the stated overload of the Hovland phono stage of 0.9 mv (millivolt) I thought was meant to be the maximum output level of the cartridge, am I wrong here?
Hi Rlawry, looks like increasing the gain in the Hovland is not an option, and the volume taper (I don't know what a taper is, behind the volume knob there's a chunky thing full of resistors) has been designed that way for a reason, according to mr. Crespi. The power amps option sounds interesting though, I didn't know you could increase their gain, does that mean increase power? I'll try to talk to the manufacturer, that should be much easier being Mastersound an italian brand. I wonder though, if I could do that and fix the problem with LPs, woudn't I end up having the opposite problem with CDs, I mean not being able to go beyond 9 o'clock?
Thank you all,
Marco |
Hi Larryi, I agree it's not going to be easy to find a suitable alternative to the Colibri, i read something about Decca London and I don't think it's for me, at this time I'm curious to hear about the Clearaudio Titanium (0.8 mv), suggestions are welcome. The tube rolling suggestion is indeed interesting, also Rlawry said something about that, he named Mullards, you Amperex, looks like my options are widening thanks to you guys. I know the stock tubes are mediocre, Hovland don't encourage rolling though, they say the unit has been optimized around those tubes. To their credit, I have to say that I tried putting some telefunken NOS, but i went back to stock tubes because, even though there was a very slight improvement in noise, I felt I lost some depth in soundstage. After that first experiment, I gave up tube rolling, but after your reports maybe I should try harder. I will also make sure the unit is not defective, thank you. |
Hi Thekong, yes since your first post I've been checking out VdH website and I saw what you're talking about, a trade-in would be very well worth considering.
Rlawry, I think I'm gonna be pretty busy for the months to come to explore all the options, comparing costs and sonic advantages, one italian hifi magazine lately reviewed your preamp, the CAT Ultimate phono, plenty of gain and killer sonics but expensive, it kinda turned me on.
Hi Piedpiper, yes that will probably be my first attempt, I just have to figure out how to start, I mean which tubes to buy first and where.
Again, I want to thank all of you guys for all the inputs, I'll get back to you with my findings.
Cheers,
Marco |
Thanks Piedpiper, nice system btw. |
Hi Gregm, ok now I understand, it totally makes sense, it's those 7 dB that make me turn the volume so high.
Hi Undertow, let's see, my triangles are 93 dB and my amps are 50 watts, I think those 8 dB difference on speakers outweight the 30 watt difference on the amps, so that makes sense too. I have to say though, that with digital I'm totally happy with the volume at 12 o'clock, I can't go beyond 1, and that's an area that, even when the phono input is selected, is pretty quiet. So, while I still want to try some more tube rolling, looks like one day I'm gonna have to get a new cart, one with a higher output that won't make me miss the colibri. Options are:
-Another colibri @ 0.65 mv, would those be enough?
-A Shelter 9000 (0.6 mv) or Air Tight PC1 (0.6 mv) same as above
-A Clearaudio Titanium (0.8 mv)
-You name it
Thank you all,
Marco |
