I use a hybrid preamp.
It has a discrete transistor "opamp" front end and a tube buffer output.
When I built the thing I provided a switch to take the output from straight off the SS stage or from after the tube buffer.
Guess what:
When I'm using a tube power amp I prefer the sound when the pre output comes straight off the SS stage.
When I'm using an SS power amp I prefer the sound when the pre output comes of the tube buffer.
That means I prefer a bit of "tuby-ness" but not too much and While I prefer the SS Pre / Tube Power Amp combination there is not a lot in it.
The tube pre / SS power amp is certainly a cheaper option.
Cheers,
Ian
It has a discrete transistor "opamp" front end and a tube buffer output.
When I built the thing I provided a switch to take the output from straight off the SS stage or from after the tube buffer.
Guess what:
When I'm using a tube power amp I prefer the sound when the pre output comes straight off the SS stage.
When I'm using an SS power amp I prefer the sound when the pre output comes of the tube buffer.
That means I prefer a bit of "tuby-ness" but not too much and While I prefer the SS Pre / Tube Power Amp combination there is not a lot in it.
The tube pre / SS power amp is certainly a cheaper option.
Cheers,
Ian
If I were using only CD as a source then I probably wouldn't care to have a preamp at all. Most modern recordings are very poor and the point was made about the number of op-amps in recording consoles. From my perspective, I have about 1500 LPs and many of them are classical, direct-to-disc, or were recorded before the age of op-amps or even transistors. These are more important to me than CDs so an RIAA amp is absolutely essential. It makes sense to me to use valves to reproduce these recordings as faithfully as possible. I've used 4558s, 5218s and 5532s from time to time as well as discrete transistor amps but none have pleased me as well as those based on valves.
mmmmm.
Yep, you will get all comers with this. I can say for after many direct, TVC, etc, etc,, that a good low gain DHT is far & away what I prefer. Just seems to add that presence & holographic nature that all other have failed with me, especially TVC. I have some good DHT amps that do this on there own. but one can cheat w/ good DHT pre. 26, 10, etc.. even IDHT 27 do the stunt work very well. I also do not in any way believe in the word Neutral. I voice em the way I like em.
Yep, you will get all comers with this. I can say for after many direct, TVC, etc, etc,, that a good low gain DHT is far & away what I prefer. Just seems to add that presence & holographic nature that all other have failed with me, especially TVC. I have some good DHT amps that do this on there own. but one can cheat w/ good DHT pre. 26, 10, etc.. even IDHT 27 do the stunt work very well. I also do not in any way believe in the word Neutral. I voice em the way I like em.
To me there is no question. A low gain circuit between source and amp, matches and buffers. Every time I use a dac straight to an amp, it sounds flat. Use a good triode valve single stage in between and the music livens up. For cd, X6 gain caters up to 2VRMS sens amps with good rotational arc on the volume control. More, is excessive and noisy.
My power amp for my main speakers has a volume control on it. So does the amp in my subwoofer. Problem is, if I want the music louder or quieter i have to rebalance the level of at least two amps. A real pain in the ***. Also, I have several digital and analog sources. My wife certainly can't be bothered to plug and unplug cables every time she wants to listen to a cd. Just flipping a switch or pressing a button would keep me from having to listen to complaints about my music system being too complicated.
I need a preamp.
I need a preamp.
analog_sa said:
The Pumpkin does the job as well as any pre, and it will drive just about anything.
As for the sound, I'd say it sounds very neutral. I've heard it in a couple of different setups by now.
Magura 🙂
Several people have brought up whether a line stage is even needed, and if you have a significant line, it probably is. OTOH I rarely go more than a foot or two, so a 7 kohm stepped attenuator is all I need or want. I use low capacitance cable. My vinyl goes through an LME opamp preamp, then the attenuator, and that's more than enough output and drive capability for any of my needs. No complaints with the tube preamps I've had, they sounded fine, but I don't think they were any better than my solid state unbuffered preamp.
Trivia question- does anybody remember Ace Audio, and their "zero distortion" modification to their preamp? The mod consisted of removing the line amp stage, and making everything but the phono, passive. Were they the first?
Trivia question- does anybody remember Ace Audio, and their "zero distortion" modification to their preamp? The mod consisted of removing the line amp stage, and making everything but the phono, passive. Were they the first?
rdf said:
That would certainly be my motivation, plus the thought of spending a lot of money on stepped attenuators is hard to contemplate. (I hate pots! And will never use them again. Use even a cheap attenuator and you will probably understand why.)
SY also has a good point, unfortunately these days I build stereo amplifiers with outboard supplies, so I can't place them next to the speakers, but the power amplifiers are generally not too near the sources in any case. (My current speaker cables are litz wire and each bundle is about the size of a #4 conductor, flexible too. I haven't heard anything I like better in 15yrs or so I've had these, hopefully they are close to "blameless" cables. 😀 )
I have a separate phono stage, line stage, power amplifier, power supplies, passive x-o, etc. My entire system is modular which allows me to change one aspect of the system and assess the result without a whole lot of other things changing as well. Gain in my case is a moderate 4dB, transformer coupling is used which allows me to easily switch output polarity, balanced or unbalance operation can be arranged and the source impedance is around 300 ohms - low enough to allow just about any kind of cable I desire, and over long distances if necessary.
It's my experience that in a properly matched system (in terms of impedences, resolution, other synergies, etc.), a tube preamp does have a unique sound signature when compared to a solid state or chip-based preamp.
I won't go into too much detail, you'll have to listen and decide for yourself whether you like the particular flavor of either the tube or solid-state pre not. Both have their character and one is not necessarily better than the other.
If you cannot hear the difference between the two in your system, then by all means go for the solid state preamp. SS pres are generally more efficient (they use less energy than a tube pre, especially the chip-based variety, afaik), and chips or transistors are much less fickle and fussy than tubes. Tubes can also be noisy or microphonic.
On the otherhand, if you like what a tube pre brings to your system, the sound that a tube pre offers may trump the cons.
It really depends on how the pre, tube or solid-state, works within your system to give you the kind of listening experience that you like.
For the record, I've had tube, solid-state, chip, and TVC preamps in my various systems and have preferred a good tube pre with SS poweramps, and a good solid-state pre with SET or tubed power amps.
Best,
KT
I won't go into too much detail, you'll have to listen and decide for yourself whether you like the particular flavor of either the tube or solid-state pre not. Both have their character and one is not necessarily better than the other.
If you cannot hear the difference between the two in your system, then by all means go for the solid state preamp. SS pres are generally more efficient (they use less energy than a tube pre, especially the chip-based variety, afaik), and chips or transistors are much less fickle and fussy than tubes. Tubes can also be noisy or microphonic.
On the otherhand, if you like what a tube pre brings to your system, the sound that a tube pre offers may trump the cons.
It really depends on how the pre, tube or solid-state, works within your system to give you the kind of listening experience that you like.
For the record, I've had tube, solid-state, chip, and TVC preamps in my various systems and have preferred a good tube pre with SS poweramps, and a good solid-state pre with SET or tubed power amps.
Best,
KT
Several posters in this thread have made mention of an extra oomph or je ne sais quoi or {flashy words here} with a preamp in the chain. While I won't debate this, I just have to admit it makes me scratch my head even more. I mean, a LOT of the people on this forum design and build both their own preamps and power amps. So, when there is this blank sheet in front of you, why aren't you building your wonderful/magical sounding preamp inside your power amp?
Many can't afford to just go out and build a complete stereo (or however many channels) system in a box all at once. I also like the freedom of adding options as I think of them (sometimes months or even years after I built my power amps).leadbelly said:
leadbelly said:
See the post by rdf or me above.. 😀 I have 4 sources, and can't afford to put a $1 - 2K cup of magic sauce into every one of the numerous power amplifiers I have built or will build in the future. For me a single line stage makes sense, that way I only have to invest once in the stepped attenuators, the Shallcross rotary switch, and all of the vampire rca jacks, tcss wire, etc.. Maybe I am a crackpot, but after years of cheaping out and using inexpensive ALPS pots, and connectors I have discovered that the better parts actually make a difference I can easily hear. Some of the differences are measurable like the HF response and distortion with the stepped attenuator as compared to a pot of comparable value, others are impossible to quantify, but seem to do something even if I cannot figure out how to measure it.
leadbelly said:
I did just that. If one has test equipment and analyser, then the self imposed challenge is on. My main amp has a s/n ratio of -80dB down. The trump card with the preamp is not to contribute to this, in otherwords it must be bettered when the volume and treble controls are maximum.
Designing a preamp line or low level will draw ones sap and midnight oil...but it can be done. You'll get away with pentodes strapped as triodes but not true pentode operation.
I used EF86's as triodes (better b/w)and a paralled sectioned ECC88 as parafeed follower into a stepdown to give 600 ohm o/p. Had I known, I'd wish I had the 6BR7, which is a better and quieter tube.
It was the headphone amp that caused all the problems. I haven't come across a good tube noiseless headphone amp that
can drive 8 ohm lugs with -90dB noise down.
richj
rdf said:
I'll agree with rdf, but also add that it doesn't matter. The opamps, if they are there, are, what the economists call, sunk costs. The recording is what it is. If you are at an art museum, just because some painting probably could use some restoration and is a little duller than it might be is no reason to not bother putting on your glasses to look at it.
Trivia answer....
Never heard of Ace Audio but I have had a Precision Fidelity C9 - and am now using the Precision Fidelity C7 (waiting for parts to upgrade and convert to C7A revised). It is a phono section with bypass for other line level inputs. There is no line stage other than the passive VC (soon to be replaced with proper attenuators).
It hammers - on all subjective fronts - a couple of pre-amps I have here which originally cost thousands of bucks! These Bruce Moore 'oldies' must be the vintage bargain of all time: but then all his stuff sounds good from what I hear!
Conrad Hoffman said:
Never heard of Ace Audio but I have had a Precision Fidelity C9 - and am now using the Precision Fidelity C7 (waiting for parts to upgrade and convert to C7A revised). It is a phono section with bypass for other line level inputs. There is no line stage other than the passive VC (soon to be replaced with proper attenuators).
It hammers - on all subjective fronts - a couple of pre-amps I have here which originally cost thousands of bucks! These Bruce Moore 'oldies' must be the vintage bargain of all time: but then all his stuff sounds good from what I hear!
kevinkr said:
For 15 years my 'pre' has been a four section Greyhill rotary selector followed by a pair of Bourns 10K 10-turns. The Greyhill is wired with mute positions between every input, ground and hot switching, and all solder terimals carrying signal or ground isolated from each other by an adjacent terminal referenced to the output ground. All unused sources are completely disconnected from the amp and the 'pre' doesn't add additional ground references between source and amp. My far more objectivist brother for a decade considered it audio frou-frou. A couple years back he surprised me by building a similar unit unannounced and raving about the sound. I haven't heard it but he claims the extra detail is jaw dropping. One his first pre's was a Cory Greenberg special so it's not newbie love and he has the technical resources to make quality measurements.
If I were to live with a single amp the leadbelly option is the only one which makes sense to me. It eliminates a whack of electronics and third ground reference between amp and pre.
I've found that a preamp is a useful tool, but not for all occasions. Some power amps expect a hot preamp signal to provide enough gain and this is where a preamp can be useful. My Marantz 8b likes it hot especially when moderately efficient speakers are used and more power is demanded for listening. I could imagine this becoming more pronounced with low efficiency speakers and high power amps. It greatly depends on the power amp though.
My SimpleSE and high efficiency speakers are happier without the preamp interestingly enough.
Some sources don't have a very strong output or perhaps prefer a higher resistance from their output. My cheap mp3 player likes the preamp very much regardless of the power amp.
My SimpleSE and high efficiency speakers are happier without the preamp interestingly enough.
Some sources don't have a very strong output or perhaps prefer a higher resistance from their output. My cheap mp3 player likes the preamp very much regardless of the power amp.
whitelabrat said:
Ditto. Two of the tube amps I own have no volume control, and I am haunted by the possibility of not having enough gain to drive my different speakers. Since my CD player has no adjustable gain, and my soon to be phono stage will have no gain, it seems necessary that i'll need headroom one place or the other. I'm using a half-finished aikido amp with a noble pot and it sounds clean enough.
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