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Need advice on Tube setup for Heresy II and RF-7


ssd008

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Hello everyone!

I have been happily enjoying my Heresy IIs for about 2 years now. I just got a fulltime job and decided it might be time to try looking into tube amplification. I have been trying to read up on it and what is available but am so far somewhat overwhelmed. I am looking for suggestions on a good tube preamp and amp that would be able to power the Heresys and potentially a set of RF-7s. So without further ado, here are a few of my questions:

  • What are some good brand/model tube pre amps to use with these speakers? (audio source will most likely always be a computer)
  • What kind of tube amps should I be looking for? (Vintage, New but in kit form, new, etc)
  • Would a pair of monoblock tube amps be more advantageous than a stereo tube amp?
  • How many watts should I be looking for when considering tube amps?

From the research I have done, one of my favorites so far is the Dynaco ST-70. It seems to be a popular starter amp and has a large and knowledgeable user base that I could tap into for help if needed.

Thanks in advance for your help and patience with me while I embark on this journey!

[:D]

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Your question doesn't have an easy answer as much depends on the listening environment. How large are the rooms in which you listen? What kind of furnishings are there (i.e. carpets, drapes, rugs, book cases, etc.)? What type of music do you listen to and how loudly do you listen? Where is the listening position in relation to the speakers? Why do you feel the need to have a separate preamp and amp as opposed to an integrated amp? The one question which can be answered now is about going with monoblocks. Stereo amps, depending on their power supply design, can have varying amounts of crosstalk (i.e. interaction between the 2 channels which can reduce the perceived channel separation). Going the monoblock route limits the crosstalk to that of the source. Some people can hear crosstalk differences, and others can't. The bottom line, once you have made some decisions, is to find a way to audition the amps in your system. It's the only way to know if the sound is what you are looking for.

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Hmm. There's just gotta be some Klipsch dudes in Chi town who use tubes and would want to show off their systems. Any takers, Chicago forum members?

Once you do the preliminary work that tf went over and you have your choices narrowed down, look in the used market. Friends don't let friends pay retail.

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2Q==

Will be listening to everything in the living room of my new apartment. The floor is carpet and there will be a couch and a loveseat in a fabric material. Couch will be on 10.5' wall, media center and speakers opposite, loveseat on the window wall. The other thing to note is that the ceiling slants up to a somewhat open loft area that is on what would be the right of the couch if you were sitting on it.

Will be listening to all sorts of music (pop, movies, movie soundtracks, musicals, etc) at whatever volume doesn't get us in trouble with the neighbors. [Y] But seriously, I don't think it will be super loud.

On the seperate vs integrated issue, most of my research has been about seperates, but I am open to suggestions for either!

In terms of budget, I am probably looking for bang for your buck starter equipment. If I like tube sound, would be nice to enjoy the system without getting an upgrade bug for a little while. I'm sorry this is a somewhat vague answer. I will be actually starting my new job soon and will know more as my finances and expenses settle out.

Thanks for all the responses so far!!!

post-38709-13819659503918_thumb.jpg

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If bang for the buck is your goal I'd go with a well respected rebuilt vintage integrated amplifier or receiver. These will out perform a "budget" entry level separates system of the same cost range with no headaches in matching of what preamp works with what amplifier. They almost always command near the investment spent upon resale and sound great. Many folks get a nice working one and never move on. Others keep them since they sound so good for a second system when they dive into the separates game later on down the road.

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NOSValves doth speak the truth! But I wanted to add my slightly different opinion on this, on the chance that it might help you.

Since your source will be a computer, it's likely that you don't even need a line level preamplifier (the preamp section in an integrated amp or receiver, or a separate preamp like the Dynaco PAS). Most power amps can be driven to full power with less than 1V RMS of signal from the source (that's equivalent to 1.414V peak). The standard maximum (0dBFS) output level from a CD player is 2V RMS (2.83V peak), so most any CD player can drive most any power amp to well beyond full power.

Also, since you'll be using a computer as your sound source, it's likely that you will already have a volume control in its audio player software. Since you already have a digital volume control, why add a potentiometer (variable resistor) or stepped attenuator volume control? You actually don't need it. In audio, less is just about always more. Less passive hooey in the signal path will mean cleaner sound -- but possibly less convenience.

So here's an idea for you -- Use your computer as the control center for your sound, including its volume control. Make sure you equip your computer with a really good sound card that puts out at least 2V RMS at 0dBFS (full scale, or the loudest level it can play). Then get a good quality, vintage stereo tube power amp, such as the Dynaco Stereo 70 ("ST70"), or the Dynaco ST35 (the little brick-shaped one with the 6BQ5 or EL84 output tubes). The ST35 is a really nice little amp, puts out an advertised 17.5 watts per channel. It might only be 15 watts per side in real life, but that's enough for most small apartments playing at moderate levels into efficient loudspeakers. I personally prefer the sound of a stock ST35 to a stock ST70. Other vintage power amps worth buying are from Fisher, McIntosh, Marantz, Eico, Heathkit, harman-kardon, Quad, Luxman, and so on. Dynaco will most likely be the easiest to find in good condition for reasonable cost.

If you must have a volume control, selector switch and tone controls on the amp, and you are looking to spend about $300 to $600, you could do a lot worse than an H.H. Scott 233 or 299 model integrated amplifier. These have a 'romantic' sound to them, mostly because of their old school circuitry (including tone controls). There are others from Fisher, Eico, Heathkit, etc. But the Scott amps are the most common. The Dynaco SCA-35 is basically an ST35 power amp with a built in PAS preamp, in one box. The preamp circuit doesn't sound all that great (in my opinion), so I'd still recommend the ST-35 power amp over that... or a Scott or Fisher.

Anyhow... I'm sure somebody will disagree with that approach, but I thought I'd lay it out there for you. Whatever you decide, I'm sure you'll enjoy it.

--

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NOSValves doth speak the truth! But I wanted to add my slightly different opinion on this, on the chance that it might help you.

Since your source will be a computer, it's likely that you don't even need a line level preamplifier (the preamp section in an integrated amp or receiver, or a separate preamp like the Dynaco PAS). Most power amps can be driven to full power with less than 1V RMS of signal from the source (that's equivalent to 1.414V peak). The standard maximum (0dBFS) output level from a CD player is 2V RMS (2.83V peak), so most any CD player can drive most any power amp to well beyond full power.

Also, since you'll be using a computer as your sound source, it's likely that you will already have a volume control in its audio player software. Since you already have a digital volume control, why add a potentiometer (variable resistor) or stepped attenuator volume control? You actually don't need it. In audio, less is just about always more. Less passive hooey in the signal path will mean cleaner sound -- but possibly less convenience.

So here's an idea for you -- Use your computer as the control center for your sound, including its volume control. Make sure you equip your computer with a really good sound card that puts out at least 2V RMS at 0dBFS (full scale, or the loudest level it can play). Then get a good quality, vintage stereo tube power amp, such as the Dynaco Stereo 70 ("ST70"), or the Dynaco ST35 (the little brick-shaped one with the 6BQ5 or EL84 output tubes). The ST35 is a really nice little amp, puts out an advertised 17.5 watts per channel. It might only be 15 watts per side in real life, but that's enough for most small apartments playing at moderate levels into efficient loudspeakers. I personally prefer the sound of a stock ST35 to a stock ST70. Other vintage power amps worth buying are from Fisher, McIntosh, Marantz, Eico, Heathkit, harman-kardon, Quad, Luxman, and so on. Dynaco will most likely be the easiest to find in good condition for reasonable cost.

If you must have a volume control, selector switch and tone controls on the amp, and you are looking to spend about $300 to $600, you could do a lot worse than an H.H. Scott 233 or 299 model integrated amplifier. These have a 'romantic' sound to them, mostly because of their old school circuitry (including tone controls). There are others from Fisher, Eico, Heathkit, etc. But the Scott amps are the most common. The Dynaco SCA-35 is basically an ST35 power amp with a built in PAS preamp, in one box. The preamp circuit doesn't sound all that great (in my opinion), so I'd still recommend the ST-35 power amp over that... or a Scott or Fisher.

Anyhow... I'm sure somebody will disagree with that approach, but I thought I'd lay it out there for you. Whatever you decide, I'm sure you'll enjoy it.

--

Actually I didn't catch the computer as a source part of the equation. The above advise is very good!

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Thanks for all the great advice!

I will turn my research efforts towards an integrated tube amp and see what I can find. I saw quite a few recognizable brands in the last few posts.

Any specific models I should be trying to look for or find deals for?

I appreciate all the help!

[:D]

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A nice Fisher ready for prime time is listed in the for sale section now. It has my deluxe rebuild warranty standing tall behind it. For as long as I'm still breathing and able to solder I fix any amp I have preformed a complete deluxe rebuilt or built new for a basic $50 bench fee plus shipping cost no matter who I performed the work for originally. The only type of failure that I would not cover the parts would be parts I did not replace in the original deluxe rebuild like transformers and stuff like that. Pretty darn safe purchase...

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I have several tube amps with my Klipsch. Check out a company called Antique Sound Labs. The models I have had and enjoyed are the AQ1003 DT and the Mg-si15DT. These are both integrated amps and also have a nice remote control for them as well. I got them both used on Audiogon.com for about $500 each.

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I have several tube amps with my Klipsch. Check out a company called Antique Sound Labs. The models I have had and enjoyed are the AQ1003 DT and the Mg-si15DT. These are both integrated amps and also have a nice remote control for them as well. I got them both used on Audiogon.com for about $500 each.

I heard a pair of Antique Sound Lab monoblocks with 6L6GC output tubes. They sounded pretty good to me. I even got the chance to open them up and look inside. Good quality, well-made stuff for a reasonable price. You could do a lot worse.

-=|=-

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A nice Fisher ready for prime time is listed in the for sale section now. It has my deluxe rebuild warranty standing tall behind it. For as long as I'm still breathing and able to solder I fix any amp I have preformed a complete deluxe rebuilt or built new for a basic $50 bench fee plus shipping cost no matter who I performed the work for originally. The only type of failure that I would not cover the parts would be parts I did not replace in the original deluxe rebuild like transformers and stuff like that. Pretty darn safe purchase...

Safe purchase indeed!!! I will keep a special eye out for these in the for sale section.

Any opinions on Yaqin products? I ran across them surfing through products on ebay. They seem to have some favorable reviews here and on other forums.

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I agree with the vintage options mentioned above. I gave my dad a pair of Heresies and Dynaco ST70, and the two work virtually ideally well, and can play loud and clean (if that's what's wanted) without distortion. Not that an integrated wouldn't be as good (a subjectively determined thing), and an integrated does not need a separate preamp.

In addition to the Dyna 70 that I found to be such a great match for Heresy IIs, was an amplifier from a company on the east coast called Sophia Electric. Some of their products are expensive, but my wife bought me a Sophia Electric 'Baby' as a Christmas present a few years ago, because she thought it was 'cute.' It is a neat (and very heavy for it's size) little amplifier, but its sound quality reaches well beyond what one might expect from an amp of such diminutive proportions. Honestly, it's an extremely good amp for its type, and was a good match for every Klipsch speaker with which I tried it -- Heresy Is and IIs, La Scalas, and Klipschorns. One Caveat: output tubes seem to be only available from the company. I bought several quads to have on hand, though the driver stage amplifier is common.

Vintage, as Mark and Craig expressed, is always cool. The Dyna 70 I had took a bit to quiet down, but I figured out a completely new grounding scheme that worked so well I thought I had forgotten to connect the speakers. It was that quiet compared to the stock setup. The input impedance of the Dyna 70 is quite high at around .5 meg ohms, and can work with a passive attenuator in front of it.

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...The input impedance of the Dyna 70 is quite high at around .5 meg ohms, and can work with a passive attenuator in front of it.

Or with the volume control in your computer's audio player software! You only need to go straight from the computer audio outputs to the power amp audio inputs. Connect the speakers to the amp. You are done, and that would be the best "purist" system option. No tone controls or balance controls to get in the way, no preamp circuits to add noise, etc. --------- 1960s tube power amps were all designed with very high input impedance so they could be driven by the tube preamps of the day. Any of those amps will be easily driven by just about any computer sound card or DAC. That makes for a simple setup. --------- I would be suspicious of Chinese-made budget tube amps. Their parts quality might be suspect and they might not be so easy to repair. Vintage USA-made tube power amps are relatively easy to repair (often point-to-point wired) and were made exceptionally well compared to much of today's throwaway electronics.

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All very good points regarding directly driving an amp like the Dyna from a source with volume control. I've done that here with our squeezebox Touch, and there is quite.honestly not much I would change. As Rongon mentions, no other circuitry to get in the way. As also explained, the input sensitivty and high impedances of these great old amps are very sympathetic loads for present digital sources, and don't really need voltage gain of line amplifiers -- unless of course one happens to like what the insertion of a line stage, tube or ss, does for the end result. All up for grabs in that respect.

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