Are mono tube amps my best choice?

I own a Denon 5910 multi disc player as my only source, which I’ve been running into a Burson buffer gain device, and then through two separate passive volume controls. From there I’ve been feeding my four B&K M200 mono amps to my Silverline Grandeur ll speakers. This setup actually sounds pretty nice.

Because my M200s are now over twenty years old, I’m thinking about switching to mono tube amps. I’ve never had tubes in anything I’ve owned. Because my wife and I watch movies (and listen to music), I don’t have space in the middle of the room for a single amp (only 4 inches of height). My stands, passive preamp, and wiring are geared for mono amps.

I live near Sacramento, California, and emailed Min at tubeaudiolab with my room specs and setup to see what he thought would work best. He recommended a pair of mono amps with Kt 88 tubes that produce approximately 60 watts per channel. From the reviews I’ve seen, it appears Min makes some pretty good equipment.

I’m hoping for some Audiogon wisdom to show me the way. Am I making the right choice switching to tube amps? I don’t want to spend more than $2000.
Your speaker system has the efficiency to work well with tubed amps. There is much musical enjoyment to be gained by making the switch to tubes, IF you don't mind the minor added maintenance(personal viewpoint) that tubes require. I'd strongly recommend you audition any amps you are considering, in the system, before making the switch though. The capacitors(and other components) used in some people's designs can produce some very unnatural colorations that may not appeal to your tastes. Just a couple suggestions, based on personal experience with Cary products, their build quality and excellent presentation: (!-u) (
Yes, you will benefit from an upgrade to tubes. Suggest you look at the Cayin VAS line. They have mono blocks. I have two pairs of the VAS units and I have been very happy with each system I use them in. I also have a vintage pair Sound Valves that also sound great. I drive ProAC speakers with all these amps.

Best way is to find a dealer that will loan you a pair to try, nothing else will tell if the fit is right. They need to be audition in your system.
A consideration if you are running 4 tube amps in a small area will be the heat generated.

I never realized that when I had a large basement listening area. When we moved to a smaller house and I was relegated to a bedroom (12 x 14) for 2 channel listening my Atma-sphere M60's heated the room like a sauna. It saves heating in the fall/winter but is uncomfortable after about an hour in the summer.
I find it interesting that your considering going from 400 Watts per channel to 60 Watts per channel.
Rodman99999 / Buconero177

Min just emailed me that he only has one amp to audition. It's his reference amp based on Western Electric Model 91A 300B circuit. It's a single ended stereo amp that puts out 9 watts per channel. He say's that he makes this in a mono version also. Any idea if there is enough power for me to even consider?


I am going to be running just one pair of tube amps--if I buy them. Thank you for making a point about the heat generated by tubes.


I had heard that watts are less crucial with tubes. Do you have experience with tubes as compared to solid state? I would appreciate your input.
The issue of tube Watts vs. ss Watts had been disussed ad naseum here, you might want to check the archives. Your speakers certainly appear as though you might not need the all the power you previously had, but your proposed change is quite significant.
Even at a sensitivity of 93.5db(2.83V), I wouldn't bother with a 9wpc amp(or pair) for viewing movies with your speakers. There just couldn't be enough bass drive for any realism. You never mentioned what listening levels you enjoy(BTW). Yes- It's true that tube amps seem more powerful than SS, for a given power rating. Whether this is because they clip more gracefully(no square waves or high, odd order distortion), or have more reserve Joules(do to the higher operating voltages)in the power supply, isn't really fully understood. Something you might consider though: Using tubes for your mids/highs, and a pair of your existing amps for the bottom end. You're using two attenuators anyway. Are they stereo? If so- You could try that with Min's SET(though I'd still recommend something around 60wpc).
I think the person you should be asking is the designer of the speakers and not a tube designer you have taken a liking too. I would ask Alan Yun at Silverline what he thinks. Personally, I think 9 watts driving Dynaudio drivers is way to little.
Thank you for your input.

I emailed Alan at Silverline, and am waiting for his response, which I will post as soon as he replies.

Thank you, Kevin
Do you want to run tubes on the entire speaker or keep the B&K's for the bass modules and tubes on the mid and high frequencies?
1) More important than a speaker's sensitivity rating is its impedance & phase curves.

2) IF the speaker is an easy load - and Silverline supposedly makes speakers that are - a 9W SET could well be a very good match at 93.5 dB/W.

Let's do some quick, basic math here. 93.5 dB/W at 8 ohms gives you 93.5 dB for one watt pulled at one meter. The second speaker gives you another 3 dB. Your listening distance - say 3m - costs you about 10 dB. You're now at about 86.5 dB for one watt. However - that's anechoic. Even in a large room you're going to get *at least* 3 dB of room gain. So, you're at 90 dB now for that one watt - 90 dB is loud. How loud do you want your movies? Well, even if you want peaks of around 100 dB, which is really freaking load, this setup can probably do it.

When I had 90 dB/W Hyperion speakers, a 16W 211 SET amp was able to play them louder, with much better bass dynamics, than a 200W solid-state monoblock.

SET amps, being class A, have very robust power supplies. An amps continuous wattage rating is meaningless if the power supply can't produce the current needed. Furthermore, and this is where it does get a little weird, there is some evidence that a single-ended valve amps can swing, for brief periods, way more voltage than their power rating would imply.

So, you might want to give it a try. However, a 300B does not have the current capabilities of the transmitter triodes.

Lastly, Min's a great guy, builds great equipment at great prices, and just might love the idea of building you a pair of 211 or 845 SETs. :)

I had heard that mixing amps isn't a good idea. Maybe someone else might like to comment on this. My setup can handle two pairs of mono amps.

You have given me something else to think about and research. After I hear back from Alan at Silverline, I'll consider my options.
Silverline voices their speakers with solid state amplifiers.
Kevine: I've been actively bi-amping my home systems since 1980, and most of that time with tubes on the top. Done correctly; the presentation is excellent.
I should have stated, "Done correctly; one can enjoy the speed, definition and dynamics of SS on the bottom and the delicacy, timbre, liquid mids, open sound stage and natural decay of notes that tubes can provide on top."

What do you use on the top end and bottom end? Please explain what you mean by "Done correctly...".

I've been to Alan's Silverline showroom. He uses solid state Pass amplifiers. But, I know Alan has also made custom tube amps to use with his Silverlines. Alan's lawyer was visiting when I was there a few years ago. He was bragging about the "sweet sounding" tube amps Alan made for his Grand La Folia Silverline Speakers.
If the Silverlines are not intended for SET and do not have a friendly impedance/phase in the bass you might get some significant colorations with a high Zout SET amp...
08-02-09: Paulfolbrecht
If the Silverlines are not intended for SET and do not have a friendly impedance/phase in the bass you might get some significant colorations with a high Zout SET amp...
It depends on the Silverline model. They are not all designed the same.
Kevine- I'm using a pair of modded Cary SLM-100s on top, and a modded TransNova 9505 on the bottom. A modded TacT RCS 2.2X does the crossover and room correction duties. By, "correctly" I mean balancing the levels of the top and bottom, as the power capabilities of your amps would be so different. An active crossover(such as a Dahlquist DQ-LP1 or a Tact) is the best way to success in bi-amping. BUT- You CAN experiment with passive bi-amping via your attenuators. You wouldn't need one on the top(tube amps), but just to bring the level of the SS amps down to match that of the mains(providing the Burson unit has a level control). You want to try tubed monoblocks anyway. While you have everything with which to experiment(when you get the tubed amps); why not give it a try? Bet you like it! =8^)

Thanks for getting back to me. This sounds intriguing. I'll do more research on this. I'm still waiting for Alan at Silverline to email me back.

I'll email Alan and ask him specifically about the SET.

I believe you did a favorable review of Min's amps. Did you sell them? If so, I was wondering why.
Min's WE91 300B monos were probably the best 300B amps I've heard (though the 300B was never my favorite DHT and I haven't had a lot of them) but I still prefer the 45.
I purchased some Cary SLM 100 mono amps locally from a very helpful Audiogoner--he answered my questions (and continues to answer) regarding tube amp set-up and maintenance). Bottom line, my Silverline Speakers love these amps. My wife and I can't believe how much more we hear compared to the B&Ks...They have all of the bass of the B&Ks...The instruments are well defined and have life...and those female vocals are something else. I know, you’ve probably heard this before, but there really is no comparison.

I have some tubes on order per the recommendations of Rodman99999 and Tvad. Rodman99999 also helped me in my Cary SLM 100 decision (thank you, thank you, thank you)—being an owner of the Cary 100s, he says that different tubes will take the Cary's to another level.

I do woodworking as a hobby (and for money on the side), and built some 7" high curly grained cherry stands (with two inch thick maple tops) specifically for these amps. With the chromed tube amps and the high gloss amp stands (with wood grain that looks like orange flames shooting upward), my wife loves the way they look in our living room (very important). Thanks to all of you that posted comments for your input. I believe I'm going to be keeping these for a long, long time.