tubes and current
The more tubes used in an amp will give it more power. Also the type of tube used will increase power. An EL34 tube is about 25 watts and a KT88 is about 35 watts. These Quicksilvers are nice amps within your budget and you can use different type tubes to change the flavor of the sound to your liking! http://quicksilveraudio.com/products/midi-mono/ |
+1 for the Quicksilver mid-mono’s. I’ve recently seen these 40w wonders drive a pair of M-series Sound Lab’s. Both the audio dealer AND Sound Lab were impressed by that feat. OTOH - Melikes KT88 vs EL34 With with respect to 845's. The only amp with that tube that I've seen and heard are deHavilland 845-G SET mono's. Enjoy! |
VAC Renaissance 30/30 MK3 can be had used for around $3K. It has four 300B tubes in push-pull configuration, generating 32 very strong wpc. I've been using a 30/30 Signature to drive my large Harbeth M-40.1's with good results. The amp generates very high current, has robust transformers and weighs in at a healthy 75 pounds, due in large part to the large transformers. Not my preferred amp for rock, but outstanding for jazz, classical, acoustic and female vocals. Music Reference RM9 MK2 is another good choice. It can be had for around $2,500. It has eight EL34 tubes and generates 125 wpc. I use it mostly for up tempo pop and rock, but it's good with all genres. Midrange magic at it's finest. Both classic amps that are sure to make you smile. |
VAC Renaissance 30/30 MK3 can be had used for around $3K. It has four 300B tubes in push-pull configuration, generating 32 very strong wpc. I've been using a 30/30 Signature to drive my large Harbeth M-40.1's with good results. The amp generates very high current, has robust transformers and weighs in at a healthy 75 pounds, due in large part to the large transformers. Not my preferred amp for rock, but outstanding for jazz, classical, acoustic and female vocals. Music Reference RM9 MK2 is another good choice. It can be had for around $2,500. It has eight EL34 tubes and generates 125 wpc. I use it mostly for up tempo pop and rock, but it's good with all genres. Midrange magic at it's finest. Both classic amps that are sure to make you smile. |
You may end up with significantly different sound by switching between amps and tubes. If you love your current sound and just need more power, you have answered your own question as to buy a second amp. However, that may not be enough power for your needs either. What 300B is your current amp? That will get you better suggestions. |
I use a Dared VP-300B. Not sure we're getting to my original answer. Hope to clarify here my original question is 'does adding more tubes increase high current of amp (not just watts) or is high current mainly determined by amp design and transformer used and not directly related to amount of tubes used'. I'm trying to understand the age old wisdom with solid state amplifier that a 1000watt amp. doesn't automatically equate to high current amp, in tube world does having lots of tubes also does not automatically equate to high current amp? Again, I don't need higher volume, I need higher current for dynamics and fuller body sound. Thanks all. |
I don't have the electrical/electronic chops to answer, maybe someone else will have to provide an answer but it seems the amplifier design, power supply and transformer that will determine current. I don't think "high current" determines what your speakers see. Speaker impedance (resistance) come into play. Room size comes into play. Your B&W's have a nominal impedance of 8 Ohms. With a recommended amplifier power rating of 50 - 120W into 8 Ohms unclipped. As long as you match the speakers impedance to the amplifier in use, so that the amp is not working overtime, you should be fine. It's when we ignore the manufacturer's parameter's that we get into trouble. |
You have a severe amp/speaker mismatch. Your amp is designed for a high sensitivity, benign impedance speaker. The B&W805 D3 is not even remotely close to being that type of speaker and better suited for a solid state amp that is stable with a low impedance load. Many years ago I tried a 2 way bookshelf speaker on a 300B SET amp I had. This speaker was not quite as demanding as the B&W with a 2db higher sensitivity and 25 watt recommended minimum power. The sound needed just what you're looking for, dynamics and more body. The proper amp/speaker match made a night and day difference in the sound of that speaker. Even though the B&W is better suited for solid state, it's possible to work with tubes, however you need to adhere to the recommended minimum of 50 watts. Some music can have dynamic peaks of 20db and more. So if you're using 1 watt, a 15db peak requires 32 watts, and a 21db peak would require 128 watts. Even with the EL34 amp you tried, I seriously doubt you were getting anywhere close to the performance that B&W is capable of. |
Your speakers and your amp are just about as polar opposite as one could get when trying to match an amp with a pair of speakers. You can read up on tube circuits, current delivery, current vs. voltage source amps, etc., etc., but the bottom line is you need to decide do you want to keep the amp or the speakers. If you decide to keep the speakers, you'll need to make a significant investment to get a tube amplifier that could drive them to their full potential. Or you could make a fraction of that investment and get a solid state amplifier that would give you all you need minus the tube "flavor". If you decide to keep the amp, look for speakers with efficiency/sensitivity of >96dB, full-range single driver or otherwise, and you'll be very happy with the results, assuming you like that sort of sound. Hope this helped. |
| Post removed |
Great suggestions by Pdreher! Given that your speakers have presumably been designed with the expectation that they would typically be used with solid state amps, and given their very widely fluctuating impedance curve (see Figure 1 of Stereophile’s measurements), what you need in addition to adequate power is low output impedance. "Low" for a tube amp, that is. Nearly all solid state amps have very low output impedance. Tube amp output impedances vary widely among different designs. SETs tend to have relatively high output impedances, and the interaction of a high output impedance with the impedance variations of your speaker will result (relative to the tonality that would result with a solid state amp) in under-emphasis of frequencies at which the speaker impedance is low and over-emphasis of frequencies at which the speaker impedance is high. Which in this case would appear to mean an over-emphasis of the upper mid-range and an under-emphasis of the bass, part of the lower mid-range, and the upper treble. Which doesn’t seem to coincide with the "lush and full bodied" sonics you indicated you are looking for. The VAC Renaissance 30/30 provides a 2 ohm output tap as well as 4 and 8 ohm taps. The 2 ohm tap will provide lower output impedance than the others. The amp also provides adjustable feedback, which will give you a lot of flexibility in optimizing tonality. More feedback = lower output impedance, but might trade off against the intrinsic sonic character of the amp to some degree. Also, the fact that the amp is very heavy speaks well of the robustness of its power supply and its ability to deliver current. In term of power capability, I suspect that its 32 watt capability in combination with your 88 db speakers will be adequate for the vast majority of classical orchestral recordings. There may be a few having exceptionally wide dynamic range, though, such as some of the older Telarc and Sheffield Labs recordings, which will have brief dynamic peaks that it may not be able to handle. The more powerful Music Reference amp Pdreher referred to is also highly regarded. That and other Music Reference amps with which I am familiar have output impedances that are considerably lower than average for a tube amp, as can be seen from their specified damping factors (damping factor being inversely proportional to output impedance). Also, Stereophile measured an output impedance of only 0.3 ohms for the original version of the RM-9. I have no particular knowledge of the Quicksilver amp that was suggested, and in particular what its output impedance or damping factor may be. Hope to clarify here my original question is ’does adding more tubes increase high current of amp (not just watts) or is high current mainly determined by amp design and transformer used and not directly related to amount of tubes used’. There are a great many design-dependent variables which affect how much current an amp can deliver. However, most amps which provide a 4 ohm or lower output tap and can provide adequate power capability for your needs will be able to deliver adequate current. What is more important, given adequate power capability and good quality design, is a suitable match between amplifier output impedance and the variations of the speaker’s impedance over the frequency range. Good luck. Regards, -- Al |
If you like the warm tube sound and love those speakers, consider a Class A amp. You might find an Aragon, Sumo or other for a reasonable price. Pass Labs will do what you need but are not cheap. Otherwise you need a big tube amp such as Cary v12. There are fairly efficient speakers out there that aren't as unique as single driver speakers if you can find them. Coincident is my favorite but you will find others rated at 92db or better. 92db will barely cut it with 8 watts. |
Here is more info on the Quicksilver Mid mono amp. There is also a 230 volt/50Hz version: Power Output: 40 watts into 4 or 8 ohms Power Bandwidth: 16 Hz to 35 KHz Input Sensitivity: 1.25 volts Input Impedance: 100 K ohms Power Consumption: 105 watts at idle 210 watts at full power Tube Complement: 1 12AX7 input, 1 6922 driver, 2 EL34 outputs I believe all Quicksilver amplifiers have the same input impedance. Input sensitivity does vary. |
