elysion
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Post by elysion on Jul 24, 2010 18:35:25 GMT
I've bought another headphone amplifier. Rabbit pointed me to the PreSonus HP4. He has also one and liked how it sounds. But this time I bought it for another purpose than usual. I need a headphone amplifier for use at headphone parties. I'm searching for cabled and wireless solutions for headphone parties. The PreSonus HP4 has four headphone output jacks and is IMO ideal for a group of listeners at a headphone party. I will need it also for a couple of concept parties that I'm planning for the near future. I like to try the concept in a small environment before I go up to bigger parties. IMO the ideal size for a headphone party is between 10 to 50 participants. I like it small. I have read also reviews before I decided to buy the amp: The first one is in French (I had no problem to understand the general conclusions in the review) with nice pictures. fr.audiofanzine.com/ampli-casque/presonus/HP-4/editorial/tests/casque-obligatoire.htmlwww.soundonsound.com/sos/jan04/articles/presonus.htmAdditional information is also available at the PreSonus homepage: www.presonus.com/The initial impression of the amp is very good. I like how it sounds with the K702 and the HD650. I will not comment about sound quality today. The amp is still absolutely new. Most likely, I will need at least 1-2 weeks for burn-in and comparison. Please be patient... There are only two things that are not optimal IMO: – The amp has no on/off switch. – The usable pot range is quite limited. The pots themselves give rather good control though. I have made a few pics of the PreSonus HP4 today... Unboxing: The rubber pads that are included in the delivery can be applied to the bottom of the amp if you use it as desktop amp: The amp itself looks great: Size comparison: A few close-up pictures:
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Post by elysion on Jul 24, 2010 23:16:07 GMT
The monitor/thru output is a great thing. It lets me connect another amp after the PreSonus HP4. At the moment, I'm using the Neco Mosfet V2 after the HP4. I hear no degradation in SQ with the Neco Mosfet V2, but I have to adjust the monitor volume on the HP4 to get the "right" loudness with the Mosfet V2. Connection from the source (Behringer FCA202) to the HP4 is over balanced mono-jacks. The output from the HP4 is also balanced (but the Neco isn't). The PreSonus HP4 has also a bigger brother, the HP60. This one has 6 headphone outputs, is rack-mountable 19-inch unit and used allegedly better components. Of course, it costs a lot more. The HP4 is a cheap amp IMO. I paid 189CHF (around 116£ at the moment). The HP60 would cost 459CHF (around 282£ now). PreSonus sells also a special rack for devices with a similar case to that of the HP4. Look at the "soundonsound" link above for some pictures.
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Post by Deleted on Jul 25, 2010 5:31:39 GMT
I have a soft spot for the Presonus. It has a warm, lush sound that for me, tames the K701 slightly in the top and provides a strong, beefy signal for the Senns. The biggest problem is getting two mono in leads. I think the idea of no on/off switch is to leave it permanently on. Having a mono switch is useful if you put a nasty hissy stereo FM radio broadcast into it. Switching to mono cleans the noise up. Also, the amp itself makes very little noise. If you set the volume at full (with no music) you don't get the riverside hiss. It's shaped so that other units can be stacked on top of it and has recesses to take the feel of any processing uits on top. I've used more than one, daisy chained together to enable mass listening. It works really well. The volume controls are small but at least they are gnurled so you can grip them. Having four headphone outs also allows you to directly compare headphones very easily, with each headphone having a separate volume control. I used this to compare the HD600 and 650 directly in the days when i couldn't (for some reason) easily hear differences. Now its really obvious, but this amp focussed my listening with the facility to directly and instantly compare at eaual volumes very easily, on the same music. What is surprising about amps is that, unlike headphones, we don't seem to use a reference amp to compare other amps to. We tend to discuss amps very individually whereas we use another headphone as a reference for new ones. I use the HP4 as a kind of reference in order to hear what other amps are doing since I have had it for quite a long time and have become used to its sound. When you compare amps, it becomes quite interesting since you then realise much more, how much the headphone is the result of a line of things and there is no one answer/headphone. A lot depends on the chain. For me, one of the most satisfying combos is the HD650/600 with the Aune amp. Mellow, deep bass and spacious sounding. Really satisfying listen and yet we tend to review the amps in isolation. However Christian, it was you who pointed out the Neco/Senn combo which does work well imo. Well, try the Aune/Senn combo. It 'may' not be your taste tonally but I find it to be very 'organic' and weighty. Lovely for rock. I think a good description is 'analogue' type sound, even with a digital signal. (Digital people will read that as coloured, but I don't care!!) I think you're one of the few people that have looked moreso at combos rather than recommend one particular headphone. For me, it's not just the headphone, it's what's in line delivering the signal and not as simple as the 'best' headphone. The Aune seems to highlight the stronger points of the Senns. It gives a warm sound with the highs clearly deliniated and a really strong bass slam which integrates well with the rest of the bass. Again, for around £100, this is an audio bargain, imo just like the HP4. I think combos are more important than headphones. When you think - the HP4 is virtually the same price as a Neco portable, then it's really not bad at all.
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Post by elysion on Jul 25, 2010 17:47:43 GMT
However Christian, it was you who pointed out the Neco/Senn combo which does work well imo. Well, try the Aune/Senn combo. It 'may' not be your taste tonally but I find it to be very 'organic' and weighty. Lovely for rock. I think a good description is 'analogue' type sound, even with a digital signal. (Digital people will read that as coloured, but I don't care!!) I don't deserve the credits for discovering the Neco/Senn combo... it was rainman who has said that he liked the HD650+Neco Portable combo. This made me listen again. For some time I was almost too fascinated with the K702+Neco Mosfet combo (which is also very good). Aune: OMG another amp! I've just bought another one (HP4). Even if Aune+Senn is the best money can buy, I guess that I won't buy the Aune. At least not in the near future. I have spent a lot of money in the last few months. BTW: I'm more for standalone DACs. I can use any amp with the FCA202 for example. I think you're one of the few people that have looked moreso at combos rather than recommend one particular headphone. For me, it's not just the headphone, it's what's in line delivering the signal and not as simple as the 'best' headphone. The Aune seems to highlight the stronger points of the Senns. It gives a warm sound with the highs clearly deliniated and a really strong bass slam which integrates well with the rest of the bass. Again, for around £100, this is an audio bargain, imo just like the HP4. I think combos are more important than headphones. In the end we are listening always to a combo. We can't focus only on one part of an audio chain. Sometimes small details make the difference. Music taste is also a factor, just like every human has unique ears. When you think - the HP4 is virtually the same price as a Neco portable, then it's really not bad at all. The HP4 is great. Right out of the box it delivers great sound with both the HD650 and K702. The only real problem is the small usable pot range. The gain is far too high. I hope that modding the gain is possible. A couple of low-impedance 'phones are almost not usable with the HP4 since the pot range is so small. Even with the HD650 and K702, I'm clearly below 09:00 with the pot. In fact I'm more in the 08:00 region... That's the only real drawback so far. The amp itself is great and soundquality is lovely.
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Post by elysion on Jul 25, 2010 18:11:04 GMT
If we talk about the AUNE, we should also have a look at the matrix m-stage. The matrix m-stage costs far more, but is almost the same as a Lehmann Black Cube Linear. It has also a built-in PSU. If I would buy one of these (very good) Chinese amps, I would go rather for the matrix m-stage.
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Post by Deleted on Jul 25, 2010 19:02:09 GMT
Overlooked imo. It's a nice amp.
I use an adapter for low impedance headphones since it's only 52 ohms out in any case. That brings the range into something more useable.
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Post by elysion on Jul 25, 2010 19:16:50 GMT
Overlooked imo. It's a nice amp. That's why I have bought one and why I have started the thread... Sound quality is really very good. I don't miss much in comparison to the Neco Mosfet V2. It's a nice listen. The HP4 also looks good. Rabbit, if you have HD580's, you should try them with the HP4 and the Neco's. I'm sure you will like what you are hearing then. They have not as much resolution as the HD650's, but they are more neutral.
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Post by elysion on Jul 26, 2010 21:50:24 GMT
Yesterday, I have tested quite a few 'phones with the HP4. It sounds good with most 'phones, but very sensitive 'phones are not optimal. Phones like the 300Ohm Senn's or the K701/K702 are working good though.
I still prefer the Neco Mosfet V2 slightly, but to be honest: The sound quality of the HP4 isn't that bad in comparison.
I'm interested to get a used K501 (or K500/K400) in the future. I'd like to test them with the Neco Mosfet V2 and the PreSonus HP4.
Rabbit, do you have 600Ohm studio headphones around? It would be interesting to test them with the HP4. Some of those multi-headphone-out headphone-amps are designed with 600Ohm 'phones in mind. I have no 600Ohm 'phones, 300Ohms are the maximum impedance that some of my 'phones have.
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Post by Deleted on Jul 28, 2010 19:13:34 GMT
Very rarely use them Christian. Basically Beyer DT150 based. Non fatiguing, tough and comfortable for loud playback. (Not particularly for hi fi) I have a habit of sitting on them and they're fine.
As for the mini-professors who sort recordings out - they all have their own weird tastes and stick with it basically. However, most monitoring is via speakers. Sorry.
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Post by elysion on Jul 28, 2010 21:44:23 GMT
My thought was that they probably have optimized the HP4 for 600Ohm "studio" 'phones. The HP4 has really a high gain which is IMO too much even for 300Ohm 'phones.
I can use the HP4 without problems with the K702 and HD650/HD580, but the pot range is very small.
With a lower gain this amp would be even better. I'd still recommend it though and I think it's a very good value. I don't regret the buy.
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Post by elysion on Aug 3, 2010 21:59:41 GMT
The PreSonus HP4 is the first amp since I've bought the Neco's that gets real attention. That means I'm listening very often to the HP4 at the moment (and my Neco Mosfet's get almost no attention).
The amp was running continuously since the thread was opened. It's a bit softer now IMO. It was never "harsh", but it's slightly smoother than before.
I'm listening mostly with HD650, HD580 and K702 at the moment. All three 'phones sound great with the amp, sometimes the Neco Mosfet V2 is slightly superior but there're also a lot things that are handled by the HP4 at least as good as with the Mosfet (if not better).
It's a good solution to compare different headphones. Four headphone outs are a luxury.
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Post by elysion on Aug 23, 2010 22:38:59 GMT
I've always wanted to try my Neco Mosfet V.2's with K501's. But I didn't have K501's then. Now I have K501's. And they sound great with the Mosfet. Even the Mosfet with linear pot an gain 3 is able to drive the K501's. I'm at 12:00 with the linear pot for normal listening. I will test the K501's more in-depth with the my other Mosfet (with log pot and gain 5) later. I'm quite happy with the linear pot Mosfet and the K501's. You can't go extremely loud with that combination, but a position around 12:00 for normal listening is almost perfect. In any case the Mosfet does IMO a good job driving the K501's. Almost the same thing with the PreSonus HP4. Driving K501's or K401's with the PreSonus HP4 is no problem. I prefer the Neco Mosfet V.2 for driving the K501's though. IMHO this amp (the PreSonus HP4) doesn't get the attention that it deserves. It's a bargain amp that sounds good and drives a lot of 'phones easily. The HP4 isn't the best amp in most areas. But overall it's very good. I'm always surprised how good it compares to the Neco amps (Mosfet and Portable). The ability to compare four 'phones at the same time with the same amp is really great. It gives me really more insight in comparing headphones. It's much easier to compare them accurately. Beside the small usable range of the pots, there's also another drawback: It's not built for low-impedance 'phones. I think it's best used with 'phones like the K702/701/601/501/500/401/400's or HD650/600/580's. The K702/701 have rather low impedance, but they behave more like the 300Ohm Senn's. I'm not really sure if this makes sense, but I must admit that I like the hard to drive nature of the K501's. They are insensitive, but in a good way. They have a touch of HD650/600/580's. They are rather forgiving (much more than the K702/701's). IMO that's a good thing. Sometimes I have the impression that my K702's let me hear thing that I don't want to hear.
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Post by elysion on Aug 27, 2010 21:47:24 GMT
Update: My SR850's with new AKG pleather pads and ClausDK-headband sounds great with the PreSonus HP4.
The SR850's are low impedance 'phones (32 Ohms) though. They are sensitive 'phones, but not as sensitive as the HD25-1/II (which gets very quick too loud with the HP4).
The main problem is still the small usable pot range. The rest is fine.
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Post by elysion on Sept 29, 2010 22:34:55 GMT
I'm still a bit suprised that this amp doesn't get more attention.
It's rather cheap, drives four headphones simultaneously and sounds good with a lot of headphones.
It has already a important place in my amp armory.
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Post by Deleted on Sept 30, 2010 4:56:23 GMT
In mine too Christian. The HD25 is way too sensitive for the HP4. Even an ipod drives them. I stick an adapter in line so they are in effect, less sensitive.
I really like it for it's sheer power and the ability to jump instantly between headphones. If you want to hear differences between headphones, it's so easy on this one.
I toyed around with the idea of a bigger set of volume knobs so that it would need more movement to change the volume, but there isn't a lot of room there.
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Post by elysion on Sept 30, 2010 22:50:04 GMT
A reduced gain would make sense. The amp would have still more than enough power. The knobs themselves aren't that bad and the tight layout of the knobs prevent the use of substantially bigger knobs.
It has also no problem to drive the K501 and K401. The 300Ohm Senn's sound also very good with it.
IMO it's also a very good amp to drive K701/K702.
It will be my choice for headphone parties. The balanced in/out enables mass listening.
I don't like the "studio" features though: The mono switch is almost useless for me and the monitor-mute switch is a no-no for headphone-party use. The monitor-level pot is also not my cup of tea. I'd have preferred a pass-throgh with a constant level (without the need to adjust anything). If you use more than one of these amps in line (daisy-chain), then you'll run easily into problems with the different loudness of the particular amps. Of course, it's also somewhat dangerous: If a user of amp1 (first in the line) accidentially changes the level of the monitor pass-through, then all users of the following amps would have instantly to much or not enough loudness. Given the powerful output of the HP4, this can result in hearing damage.
The HP4 certainly doesn't have the sexiness of amps like the PANDA, but I'm suprised how good this amp is.
Another interesting question is whether other of those "studio" amps with multiple headphone outputs have also hidden talents. PreSonus sells a few other amps and the HP4 is just the basic model.
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Post by Deleted on Oct 1, 2010 6:51:10 GMT
Yes, I found that as well. It's surprising with the Senn 600/650 and I felt that was good. However, it kind of 'mellows' the K601 which helps its sound particularly at high volume imo. I think that the amp does have quite an effect on the K701. It seems quite sensitive to changes. Recently, I've been playing around with the Buffer into an X-Can V2 and V8. In the V2 it positively thunders but keeps the clean, open sound while with the V8, there's less thunder but it is also less glaring which helps the tone of them for enormously. The V8 may be a tad more 'accurate' sounding and at first, I felt that it was a bit thin with the K701, but extended listening has proved that combo to be very revealing and now I've kind of got used to it, I quite like it. (I also changed the valves in the V8) I'm gagging to put this up with the Panda which will arrive soon. I'm still really fond of the HP4 though and have had it for a long time. As you say, great for sharing music on headphones with others and a powerful beastie. Every time I've mentioned it on the other site, no-one ever has much to say. I think that it is underestimated too Christian. Now, can you imagine that one after Mike had a look inside? I suspect there's a gem in there .... Again, at a really low price.
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Post by elysion on Oct 1, 2010 14:40:24 GMT
Maybe my mistake was that I did not post pictures of the inside of the HP4. I think the Behringer FCA202 thread would also need pictures of the things inside the FCA202.
I use both the HP4 and FCA202 very often. And they work good straight out of the box. That's probably why it was not a top priority for me to take them apart. I need them simply in working condition.
It shouldn't be that hard to open both cases and post pictures.
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Post by elysion on Feb 24, 2011 2:02:48 GMT
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Post by elysion on Feb 24, 2011 20:21:54 GMT
Before I forget it: Although the HP4 case is well constructed and solid in assembled state, it was rather painful to disassemble it. Dis-/Assembling isn't very complicated but I could easily imagine a case that is easier to maintain. The anodized blue front plate is also rather prone to scratches if tools are not used carefully.
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Post by elysion on Feb 26, 2011 0:56:18 GMT
The HP4 uses SGS Thompson MC33079 quad opamps. www.st.com/stonline/books/pdf/docs/4468.pdfThe V-DAC uses also one MC33079 quad opamp. There's a head-fi thread where someone is suggesting to replace it with LME49740. www.head-fi.org/forum/thread/425926/v-dac-modificationsThe main problem is that the V-DAC uses a DIP-14 package while the HP4 has a MC33079 in SO-14 package (SMD). I found also some information about the SQ of the MC33079 and also a few suggestions for alternative opamps: www.diyhifi.org/forums/viewtopic.php?f=5&t=268IIRC OPA4132 and OPA4134 have been mentioned also in the thread about the V-Can. The SMD package of the opamps in the HP4 is beneficial for low product cost, but changing the opamps is much more difficult. DIP-14 sockets would have been nice...
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Post by Deleted on Feb 26, 2011 1:16:46 GMT
Something else to think about. Based on quite a few people's experiences when replacing I.C.s such as the LM4562 DIP8 with a metal can version, ánd other reports about an improvement when some DIP8 dual opamps have mini adhesive heatsinks fitted, it seems possible that even though using the same chips internally, that the SOIC versions may not sound quite as good as their bigger DIP8 brothers due to running even hotter. It could be interesting to fit a small adhesive heatsink to these quads, and see if you can hear an improvement. N.B. This is just a gut feeling. Alex
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Post by elysion on Feb 26, 2011 2:48:18 GMT
Something else to think about. Based on quite a few people's experiences when replacing I.C.s such as the LM4562 DIP8 with a metal can version, ánd other reports about an improvement when some DIP8 dual opamps have mini adhesive heatsinks fitted, it seems possible that even though using the same chips internally, that the SOIC versions may not sound quite as good as their bigger DIP8 brothers due to running even hotter. It could be interesting to fit a small adhesive heatsink to these quads, and see if you can hear an improvement. N.B. This is just a gut feeling. Alex What a strange coincidence: I'm in the house of my parents at the moment and I had an old supply of Artic Silver Thermal Adhesive in my hands this evening. I've modded a few computers and video cards with additional heatsinks years ago. Maybe it's already dried up, but I'll try to use it if possible. And I have also quite a few *new* heatsinks in various sizes. Sometimes I've felt that the HP4 sounds slightly shrill. It's almost not noticeable, but for extended listening I prefer other amps which have a softer presentation. Do you think that this could have a relation with the opamps and too much heat or is it more about the sound signature of the used opamps themselves. The PSU is also a point that could be improved quite easily. The used 16V AC isn't very common though. It's really sad that the HP4 doesn't have sockets for opamps. IMO it could be very interesting to use all headphone outputs with different opamps. I'm currently reading a couple of books about soldering (in German because I need also to know how things are called German). It's very interesting to read and SMD soldering is also mentioned in the books. I almost couldn't believe that very small SMD parts can also be soldered by hand if the right equipment is used. But the needed special tools cost already a fortune and it needs a lot skills. I'm in doubt that I'll do any SMD soldering in the few years. I'll start with basic/simple soldering first and SMD soldering is only something for soldering experts with good experience. It's definitely nothing for a soldering beginner like me. Thanks for the advice about the heatsink. That's something I can do easily (as long as the Thermal Adhesive isn't dried up). Christian
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Post by Deleted on Feb 26, 2011 3:01:00 GMT
Christian Most people who have tried the LM4562HA/LME49710HA dual metal can I.C.s agree that the metal can version sounds more refined, and easier to listen to than the DIP8 plastic version. Still, most people feel the need to slip a heatsink on it, as it gets quite warm to the touch. Yet the DIP8 version has the same chip inside it, and must get damn hot internally. I think the improvement may come down to better thermal management ? Is it a coincidence that some of the best sounding I.C.s also have very low distortion figures when correctly implemented.Yet according to dusty old textbooks, we are not supposed to be able to be aware of distortion at levels 100s of times higher, as long as they are below .01% ! Alex
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Post by elysion on Feb 26, 2011 3:20:56 GMT
What a bummer! The Artic Silver Thermal Adhesive is dried up. I'll have to get new adhesive. At least, I have found a lot of new heatsinks in various sizes. Some of them will fit almost perfectly on the SO-14 cases of the MC33079. What kind of components are thermically coupled to the aluminum side elements of the case? They are clearly visible on the pictures and I assume they generate even more heat than the SO-14 opamps. In theory, I could also use some thermal paste to improve thermal conductivity between the components and the side element of the case. The metal part to which the components are connected is secured itself by a screw that connects both metal parts. To me that seems like a lot of air in between the gaps between both metal parts (respectively the components and the inner metal part). That means more than suboptimal termal conductivity between those parts. EDIT: I've found a new source for Artic Silver Thermal Adhesive already. I expect to have it in the next few weeks. Looks like that simple "mod" of the HP4 will really happen.
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