Tube shootout with the Demeter VTBP-201

[paulraphael]

Has anyone tried RCA tubes in the Dem? There are lots of different models from different vintages.

The 1960s 12au7 RCAs (pretty cheap) are so far my favorite preamp tubes in my stereo. I looked for some 12ax7 or 5751s online, but everything i found was out of my cheapskate price range. If it was more than just a shot in the dark i might splurge.

Here's part of a review from Sound on Sound; it's speculation on the signal path design and what the tube stages do:



"One of the major selling points of this unit will undoubtedly be the exclusive use of valves for signal conditioning (along with the exclusive name and individual hand-built construction). Two Chinese 12AX7/ECC83 double triodes are applied, giving four amplifying stages. Without tracing the circuit in detail, I would guess that the first stage is the guitar preamp, feeding the tone control network, while the second would be a cathode follower which has no voltage gain but provides a low(ish) output impedance to feed the effects loop output. This will allow the connection of moderately long leads, but only a few metres, it's not like a solid-state unit. If you use very long cables, the sound will become dull.

On returning from the effects loop, a second amplifying stage incorporates the volume and presence control, which you can adjust to suit your power amplifier. Most power amps have volume controls though, so I think this is unlikely to be used. It's an indication of the Demeter approach that, while some manufacturers offer signal level adjustment at three or four different stages in the circuit, this preamp gives you the opportunity to buy a plain slave amp and reduce the volume control count to one!

After the signal has been fully adjusted, the fourth stage, which is also a cathode follower, drives the main outputs. Although these therefore also have a low impedance, connection to distant PA or recording desks should of course always be made from the balanced socket."

this and a couple of others are posted on the demeteramps site.

I would definitely be curious to know what they tell you if you call about the tube positions.

 

[vicenzajay]

I will let you know know when I get a chance to talk to James. For some reason, they haven't returned my emails for about a month now...don't know what's going on. I'd really like to send my amp in for a once-over/recap/etc., but I can't get them to answer - either with the website form or straight email into the company.

Anyway - the Sound on Sound review mirrors what the circuit looks like to me...the first stage of V1 is the tone stage...thus the larger impact on frequency response (or musicality)...it looks like the gain stage of V2 does have a part to play in overall preamp gain...also makes sense that the long plate/higher gain JJ really drives the nice tones "home" from the Mullard.

Jay

 

[tombowlus]

FWIW, I did a little preamp tube shootout a while back, wherein I used my Kern as the test mule. I ended up liking the JAN Philips/GE 12AX7WA's the best, but there were a lot of strong contenders (didn't try any NOS RCA tubes, though I do have some).

Now that I have my custom 2-channel True Voice, I hope to get back to doing some tube testing.

Tom.

 

[Iridescentone]

I will let you know know when I get a chance to talk to James. For some reason, they haven't returned my emails for about a month now...don't know what's going on. I'd really like to send my amp in for a once-over/recap/etc., but I can't get them to answer - either with the website form or straight email into the company.

Huh. Please post when you get this resolved. I need to send my 201 in to fix a dead effects loop circuit one of these days. Thanks.

 

[paulraphael]

have you tried calling them? they're usually good on the phone. they seem to forget they have email at all.

i just had my 201 repaired and recapped, and they did a great job and got it back to me pretty fast. they actually repaired it within a couple of days of receiving it (charged me less than the original estimate), but then it was delayed because James was out with pneumonia and he does all the final testing/qc. After he was back in the shop, he answered the phone and gave me the lowdown, and they had it qc'd and shipped in a couple of days.

they did a much more impressive packing job than i'd done.

 

[smperry]

Has anyone tried RCA tubes in the Dem? There are lots of different models from different vintages.

The 1960s 12au7 RCAs (pretty cheap) are so far my favorite preamp tubes in my stereo. I looked for some 12ax7 or 5751s online, but everything i found was out of my cheapskate price range. If it was more than just a shot in the dark i might splurge.

I liked the RCA tubes I have in my Demeter (which I no longer own). They generally took longer to warm up than the JAN GEs but once they were ready, sounded very "round" and made the tone controls more refined or subtle. I'm holding onto a bunch of preamp tubes in case I go back to the tube amp configuration.

Marshall

 

[seamus]

For those who aren't averse to current production tubes, the 12AX7 Tung Sol reissue (New Sensor/Reflektor) has recently become a favorite in my SVP pre. They're quiet, more balanced than other current production valves I've tried, and impart a linear and predictable overdrive. My sound favors lower mids (~220), and this tube has been thick and toneful in that regard.

 

[vicenzajay]

For those who aren't averse to current production tubes, the 12AX7 Tung Sol reissue (New Sensor/Reflektor) has recently become a favorite in my SVP pre. They're quiet, more balanced than other current production valves I've tried, and impart a linear and predictable overdrive. My sound favors lower mids (~220), and this tube has been thick and toneful in that regard.

dealers for these tubes? I'd love to try one or two on the preamp.

I have no aversion to current production at all - current tubes tend to be less microphonic as well.

Jay

 

[seamus]

dealers for these tubes? I'd love to try one or two on the preamp.

I have no aversion to current production at all - current tubes tend to be less microphonic as well.

Jay

*no relation to any of the following vendors*

I deal mainly with www.kcanostubes.com and www.dougstubes.com. Both sites have the Tung reissue, and both have been exemplary and reputable in my dealings with them so far. I love the SED 6L6's Mike from KCA sent me.

Sites like www.tubedepot.com have the Tung reissue as well, but I also noticed they nickel and dime you for valve attributes like 'low noise/microphonics' or 'high gain' which in my opinion is not something that warrants a supplemental charge. I expect tubes to have already been screened for excess noise or microphonics, and requesting a high gain preamp tube shouldn't warrant a premium imo.

 

[tombowlus]

I picked up some Tung Sols from Doug Preston (www.dougstubes.com), and so far, I have been very favorably impressed with them.

Tom.

 

[vicenzajay]

Think I'm going to order a Tung Sol and another JJ short plate from him. I figure I got a bad specimen for the shootout.

Thanks,
Jay

 

[seamus]

Think I'm going to order a Tung Sol and another JJ short plate from him. I figure I got a bad specimen for the shootout.

Thanks,
Jay

For bass applications, I've read a lot more reviews of people who were underwhelmed than impressed with the JJ short plate (I'm assuming that's the ECC83S). I've seen some decent reports for bass amps using the long plate ECC803S.

Since the long plate ECC803S is purported to be about 10% lower in gain than it's short plate brethren though, I'd probably just go with a reputable NOS 5751 instead. In general, the JJ reviews I read in terms of bass amplification weren't all that compelling from what I recall.

For g****r amplification however, I am a fan of the JJ short plates selected for high gain, and the ECC803S seems to get pretty good reviews for this use as well.

 

[Big String]

I'm going to be trying some Bugle Boys 1960 short plates in my 201s soon.

 

[vicenzajay]

For bass applications, I've read a lot more reviews of people who were underwhelmed than impressed with the JJ short plate (I'm assuming that's the ECC83S). I've seen some decent reports for bass amps using the long plate ECC803S.

Since the long plate ECC803S is purported to be about 10% lower in gain than it's short plate brethren though, I'd probably just go with a reputable NOS 5751 instead. In general, the JJ reviews I read in terms of bass amplification weren't all that compelling from what I recall.

For g****r amplification however, I am a fan of the JJ short plates selected for high gain, and the ECC803S seems to get pretty good reviews for this use as well.

I was actually impressed with the low end on the JJ short plate - maybe a bit too impressed (huge low end)...Tombowlus has had good impressions of the JJ offerings for his preamps/amps, so I'm willing to give another one a shot. It it doesn't work, I'll just throw it in one of the offboard preamps I have for vocals, etc.

However, I might just pass and order two Tung Sol tubes. If they work as well as they did for your unit, I'd like to audition them in both slots.

I agree on the 803S...I actually got more overall gain on it than the short plate - but I still have a sneaking suspicion that the long plate tube is more suited for guitar amp vice a bass amp. I'm going to play the next show with it in the V2 position to see how it does with the Mullard in V1. I'll report back in any case.

Jay

 

[paulraphael]

I'm going to be trying some Bugle Boys 1960 short plates in my 201s soon.

are those amperex tubes?

i tried a friend's amperex 12au7 tubes in my stereo. huge round low end, rich, thick, gooey harmonics, soft highs. wasn't what i was after (a good thing, too, because they cost a fortune), but it struck me that these would be nirvana for some people for bass ... a real vintage tube vibe, as opposed to the modern tube vibe i normally associate with the demeter.

 

[Big String]

are those amperex tubes?

i tried a friend's amperex 12au7 tubes in my stereo. huge round low end, rich, thick, gooey harmonics, soft highs. wasn't what i was after (a good thing, too, because they cost a fortune), but it struck me that these would be nirvana for some people for bass ... a real vintage tube vibe, as opposed to the modern tube vibe i normally associate with the demeter.

Actually I believe they are not. They were made in Holland though. I've heard these sound very good in a Dem201s. I'm still learning/testing about 'rolling' tubes. Mostly it's what sounds the best and works live for me.

 

[Metal Mitch]

P.S. I think I'm done spending the time to post this stuff up here on TB. If you're not one of the "favored" few, noone (except for an isolated few) seems to read or post up on extensive review work done by someone who doesn't have 5000+ posts or enough gear to keep 25 people interested for two days. I appreciate your question, Paul (and your response, Devilman) - I'm just mystified that only two people responded...especially given the sheer number of tube preamps owned by members on this board. The one review I did that generated a decent response was the review on the budget Steelsound cab last year - go figure, it took all of about 30 minutes to get the data to write that one up. This took quite a while just to gather the tube specimens, let alone do the test, take notes, then write it up. I'll just wait until some quintuple A+ flame maple topped bass drops into my lap (I'm not a flamed maple fan BTW) - then I'll throw up some gratuitous pictures and 600 people will post about it for days. Just venting.

Well consider you only waited 2 days before writing that. And not everyone is always looking for tubes. I think people tend to look up posts on stuff they are researching for their current projects. I only found your review because I'm going through my 2nd round of looking for tubes to improve the sound of my SVP-PRO. Yes, it does take quite a bit of time to put tubes through their paces. Those of us who have been there can appreciate the work you've put into it.

And for the record, I hate quilted maple.

 

[SnakeAnthony]

Great shootout and review. I was just thinking about this a few days ago, how a 201 would respond to new tubes. I was also kind of hoping you could help me out a bit. Which tube combo produced the most vintage, earthy growl, out of the preamp. I know thats kind of a subjective tone discription, but I was still hoping you could give me your thoughts.

 

[vicenzajay]

Well consider you only waited 2 days before writing that. And not everyone is always looking for tubes. I think people tend to look up posts on stuff they are researching for their current projects. I only found your review because I'm going through my 2nd round of looking for tubes to improve the sound of my SVP-PRO. Yes, it does take quite a bit of time to put tubes through their paces. Those of us who have been there can appreciate the work you've put into it.

And for the record, I hate quilted maple.

Thus the reason for my apology post later....definitely been burning the candle at both ends (and from the middle) lately, and my patience hasn't been what it should be.

Thanks for posting!
Jay

 

[vicenzajay]

Great shootout and review. I was just thinking about this a few days ago, how a 201 would respond to new tubes. I was also kind of hoping you could help me out a bit. Which tube combo produced the most vintage, earthy growl, out of the preamp. I know thats kind of a subjective tone discription, but I was still hoping you could give me your thoughts.

Let me ponder this one a bit and refresh myself with my notes...

Still waiting on my Tung-sols, so I will update it with those as well.

Have a great weekend!
Jay