The long awaited GAS attack!

[Bloozcat]

The Eagle has landed!

I was out of town (in Chicago) over the weekend when my new Epi BC arrived. I only had but a few short minutes to try the amp out last night when I got home, so I'm reserving judgement until I've had the time to put it through it's paces for at least an hour.

There's been a bit of a buzz about this amp on some other forums, and the reviews on the amps performance have been mixed. In the short time I played through it last night, I could hear what the other reviewers were talking about. I need to confirm some information that I've read - particularly the info about this amp being self biasing - and then I'll probably start experimenting with the tubes. The consensus thus far is that the Sovtek 5881's that come in the amp are really poor. Without getting into a major explanation right now, I'll just say that I'm pretty sure that I know why they sound so bad in this amp.

Anyway, first comes the trials, then comes the mods, then comes my report. I have to believe that when it's all said and done that I'll have something good to report.

[Cranium]

Thats weird, in the specs it sais 12AX7's and EL34's, where did the 5881 come from? Also Blooz can you post some sound clips before you make any changes, I really wanna hear it in stock form.

[Bloozcat]

Thats weird, in the specs it sais 12AX7's and EL34's, where did the 5881 come from? Also Blooz can you post some sound clips before you make any changes, I really wanna hear it in stock form.

The weird specs came from Musician's Friend. The Epiphone site and all the other vendor sites said 5881's. Even with that, the tubes that came in the amp are Sovteks, which are not true 5881's anyway. Sovtek's version of the 5881 is nothing more than a re-labeled 6L6WGC that was used by the Russian military in servo amps in MIG jets. The tube will take a max plate voltage of 500 volts @ 45 watts - which is slightly more than a 6L6GC can take. A real 5881/6L6WGB is rated 360 volts @ 23 watts. I've already heard that NOS Tung-Sol 5881's don't sound good at all in this amp. I'm hoping that my NOS Philips 6L6WGB's will be the ticket. These tubes were made in the 1980's and they are rated for higher voltages than true 5881/6L6WGB's. They break up earlier than almost all 6L6GC's and have a great track record when used in old Fender Tweed amps. The plate volts on this Blues Custom have been reported at 410 volts, making the OEM Sovteks an odd choice for this amp. That voltage is between a 5881 and a 6L6GC. Now that's weird.

Unfortunately, I'm not set up to do any sound clips. That'll have to be a project for later. I've only seen two other reviews on the amp so far, and neither of them had any sound clips either. About the best I'll be able to do is to describe the tone in writing as I go through the test and the mods.

[Cranium]

Can you show me where the other review's are? Is the sound still good for a tube amp, does it have a "big" sound? I like big round sounds, hows the bass on it?

[Bloozcat]

Well, I had some time last night to sit down with the amp and try out some different settings.

First off, the overall visual appearance of the amp is quite pleasing to the eye. The fit and finish of the amp is top quality all the way. For those familiar with the Valve Jr., the BC 30 has a similar look. The tolex, while quite thick and heavier than a Fender type, is expertly applied with no flaws, misfit corners, or bad edges. The control face plate is a cream color. It is layed out nicely and it's very easy to read the markings. The EQ/volume pots are of suspect quality, though. A simple flick of any of the chicken head knobs and the pot will go from zero to dimed with no resistance. That set off a little warning in my mind. The carry handle on top of the cabinet is made of very robust leather/leather-like material, and appears quite strong. It's will need to be to lift this 65 lb. amplifier. The back of the amp is a good mixture of form and function. The 15/30 A - A/B switch is located here as well as a row of speaker output jacks. There are two-4ohms, two-8ohms, and one 16ohm speaker out jacks. Adjacent to the row of speaker out jacks is a footswitch jack. The footswitch is not included with the amp (kind of cheesy IMO). A quiet mini-fan to cool the power tubes is also located on the chassis back opposite the power tubes inside. The power cord is detachable at the amp chassis by means of a recessed three-way plug. There is no effects loop. The detachable back panel extends from the base of the chassis to the bottom of the cabinet with a neat cut-out that sports a dull black metal screen to protect the tubes. It is not only functional, but very appealing to the eye as well. I'd give the overall quality of the fit and finish a 10.

I started the test with one of my Strats in the clean channel set to A/B mode. I also elected to start with the interactive EQ. The amp in this mode is very clean, clear, articulate, and lively. The bass response is stiff and lacking in bottom end depth, but still comes off fairly well with my Strat. The EQ adjustments are responsive, but only to the degree that the OEM tube configuration allows. More on that later. The reverb is very, very nice. It has a luscious, sweet, tone with depth and a long decay. As a tube driven, spring reverb, the tone is refreshingly organic. There is no comparison between this reverb and the run of the mill solid state driven reverbs of most amps in this price range. It's not quite up to a Blackface Fender reverb, but it's pretty darn good. I'd rate the clean tone channel at: 7. It would have rated higher had the bass response been more robust.

I was definitely disappointed when switching from AB to A mode. There was little difference in the tone other that to say that the amp became noticably less lively, and lost some of it's brillance and presence. Not at all what I expected from a triode class A circuit. Rating: 6.5.

Switching to channel two in this amp was most disappointing. The tone is sterile and very solid state sounding, with pronounced treble that is bright and spikey. No amount of tweaking with the bass EQ can remove this icepick tone (without turning the tone to a muted dullness). I tried the recommended amp settings from the owners manual to no avail. While each setting did mimic the targeted tone to a degree, each setting was plagued with the icepick in the ear. Humbuckers in these settings fared even worse. Another strange tone that was present throughout the high gain settings was the presence of ghost notes that were so pronounced that it sounded as if I was using an octave pedal. Strange and annoying both. Switching from AB to A mode on channel two produced tones that were only a bit more satisfying than those experienced on the clean channel. Rating: 6.

I can't even comment on the tone of the speakers as the signal going to them was probably not sufficiently good to fairly evaluate them. Rating: N/A

Now to the tube issue. The Sovtek "5881" tubes in this amp are not 5881's by any measure of tubes. They are not true 6L6GC's either, although they'll take voltages in excess of most 6L6GC tubes. These tubes were designed for use in servo amps in MIG fighter jets. They are known for their sterility and lack of musical tone in amplifier circuits. They are by many accounts (mine included), one of the worst sounding power tubes available. IMO, these tubes doomed the amp to poor tone right from the start. The only application where they are somewhat less than horrible, is in extremely high gain amps. But, a manufacturer can put them in an amp and not worry about them holding up...you can't kill 'em. This amp comes with a 5-year warranty, so tubes like this help in that regard. Add to the output tube problem, the complement of five bland Sovtek 12AX7WA pre-amp tubes, and the circle of sterile tone is complete. The Sovtek 12AX7WA has the distinguished honor of being the most replaced OEM pre-amp tube out there.

Late last night I pulled the back panel off the amp and began pulling and replacing the OEM tubes. I replaced the five Sovtek 12AX7WA's with five NOS tubes I had. V-1 got an RCA blackplate 12AX7A, V-2 a BEL 12AX7, V-3, V-4, and V-5 each got GE 12AX7WA's. I replaced the puny looking Sovtek 5AR4 rectifier tube with an NOS Philips that looked to be a third again the size of the Sovtek. I put a matched pair of Philips 6L6WGB's in place of the Sovtek 5881's. Again, the Sovtek tubes not being 5881's at all, were about 1/2" longer than the normal short bottle 5881/6L6WGB's. The amp is cathode biased, so there's no additional re-biasing needed when changing power tubes. Despite this, there still may be an issue with the milli-amp rating of the tubes installed. The only information I've been able to garner regarding the operating voltages of the amp came from another new owner. He reported the plate voltage at 410 volts. Since a real NOS Tung-Sol 5881/6L6WGB has a plate voltage max of 360 volts, it's clear that the Sovteks that came in this amp are not 5881's...and that those NOS tubes should not be used. Fortunately, my Phillips 6L6WGB's are 1980's manufacture and are rated for voltage in the upper 400 volt range. I'm hopeful that since these tubes are known for their early break-up that they may be the tube that brings this amp to life. If not, I'll have to wait until the real amp Gurus have a chance to crack one open and start evaluating the actual circuit for tweaks (the way they have for the Valve Jr.).

Epiphone has obviously done some homework here in the design of this amp. On paper, this amps circuit should be a winner, but tubes don't live in a paper world. I fully understand the motivation for choosing the Sovtek tubes in this amp - low cost - and that was an important consideration in keeping this amp at it's price point. The problem is in that most of the buying public is made up of non-modders. Most people want a plug in and play amp. They won't be able to see beyond the bad tone to realize that there's gold under the layer of crap tone.

Tonight, I'll crank her up with the new tubes installed. Since I'm going from chumps to champs on the tube scale here, I'm expecting much better results. To be quite truthful, I wasn't expecting great performance from this amp out of the box anyway. And like with the Valve Jr., I was just expecting a great platform that could be turned into a great amp. So, this is still a work in progress.

Overall average rating: 7.38
I fully expect this rating to climb to 9.0 + by the time I'm through.

BTW: Of the two other reviews I've read, mine pretty much matches the first one I read. I don't know the experience level of the second reviewer, but he didn't seem to hear what I and the first reviewer both heard.

More to com...

[Spudman***]

Great review Blooz. I am anxious to hear what the results are.

[Cranium]

Dude whatever they tell you, you should still try to bias the tubes, maybe thats why the second channel sounds so thin and icy, I think you should check it if the tubes are too cold.

[Bloozcat]

Dude whatever they tell you, you should still try to bias the tubes, maybe thats why the second channel sounds so thin and icy, I think you should check it if the tubes are too cold.

Well, this is the way it sounds with the stock tubes, not the new ones I put in. Given the Sovtek 5881's notoriously bad reputation for tone, it's most likely the tube that responsible for the weak tone, rather than a bias problem.

Since the amp is cathode biased, it will work with a pretty wide range of tube plate currents and is self adjusting, so there is no need for manual biasing. If the circuit was a fixed bias (fixed resistor), or an adjustable bias (bias pot), then the bias or idle current would have to be adjusted.

The tubes I'm using as replacements are in a very close plate volt rating to the ones being replaced, so they will be within the range of the circuits self adjustment parameters. For these tubes to not work in this circuit would mean that the circuit was improperly designed in the first place. Since it was Pyotr Belov, a well known boutique amp builder who designed this circuit, it's not very likely that the circuit is improperly designed. Belov has a great reputation as an amp builder, and his amps have been featured in many guitar magazines. However.... there is always the possibility that the circuit is ill concieved, but that will be the last place to look. At any rate, the tubes wouldn't be damaged if the idle current is too low, they just wouldn't perform at optimum efficiency. Now if the idle current was too high...that's another story.

[Cranium]

So the sound is better now with the new tubes? Do you think it sounds better on clean channel with a pedal like a TS-9 or something?

[Bloozcat]

I love it when a plan comes together...!

Ok, I sat down tonight and ran the amp with the new tubes through the gamut. Starting with the clean channel: As before the clean is, well clean. It's clear and articulate as before, only now the bass is fuller and there's some power tube growl at higher volumes. Very nice. Clean, warm jazzy and bluesy tones come through now, with great single note definition. Switching to the class A 15 watt mode, there is now a noticable difference. There's more snap to the tone when I dug in with a strong pick attack, while the notes had a warmer rounder tone when played with a metered pace. In both modes the EQ is now more responsive. There are plenty of tones yet to be found as I didn't explore them all...yet.

On to the OD channel: Well hello, there really is an OD channel in this amp that doesn't sound like a raunchy, clipping diode solid state circuit! Suddenly there is clearly defined bass. Not just the full, deep, rounded kind, but the harder, slap kind of bass as well. You just have to dial in what you want. The thing I like about this new bass response is that it's not the least bit boomy or mushy. It is sharp, clear and punchy. Pretty cool.

After running through some of the owners manual suggested settings, I started experimenting with some of my own. My Strats will go from crisp clear, shimmering and glassy tones to really edgy OD bite. And the icepick is gone! My ears no longer feel like they've been flossed with razor wire. Every switch position on the Strats is usable...I just had to find the right EQ setting to maximize the tone. The horrible ghost tones have been reduced to a normal Strat kind of warbling sound (in high gain mode, that is). The sustain this amp now delivers make lead runs smooth and buttery. I found myself playing with a lighter touch as notes seemed to float out of the amp. When I switched to my Agile LP with the Highorders in it, a smile spread accross my face like a Chessire cat. Crisp, biting lead tones seemed to leap from the fingerboard. This guitar and these pickups never sounded this good in any of my other amps. Everything from Allman Brothers to AC/DC tones were there. Even hints of that hollow Jimmy Paige sound was there, although I didn't take the time to try to dial it in further.

It is a common notion that a rectifier tube has no bearing on an amps tone. While this is true, it has a profound effect on the sag, which in turn affects the note definition and overall shape of the tone. In this regard, the NOS Philips 5AR4 rectifier tube I put in this amp was so much better than the stock Sovtek as to make it seem that I went from a solid state rectifier to tube. There is that much of a difference.

While the speakers still have a while yet 'til they break in, at least now I can tell that they will be fine for this amp, They seem to handle all the different amp settings I tried with equal aplomb. Good job Eminence!

I did just a little tweaking with the pre-amp tubes and I'm not done yet. I changed the tubes to the RCA in V-1, a GE 5751 in V-2, the BEL in V-3, and GE 12AX7WA's in V-4, and V-5. That smoothed out the pre-amp OD a bit. I want to pick up a couple more Tung-Sol 12AX7 reissues to try out as well.

Well, with ringing ears, I'm happily off to bed for the evening. I can't wait to spend some more time with my new little jewel.

[Cranium]

Thats it, Im definatley getting one, do you think I should put those JJ's tubes from eurotubes.com, people say those are very good. Also after your done with all the testing of the tubes could you list the ones you found to sound best in the amp, thanks.

[Bloozcat]

Thats it, Im definatley getting one, do you think I should put those JJ's tubes from eurotubes.com, people say those are very good. Also after your done with all the testing of the tubes could you list the ones you found to sound best in the amp, thanks.

I'll be sure to list my final choices on the pre-amp tubes.

As to the JJ tubes. I'm not sure how any 6L6GC tube will work in this amps circuit. There has been only one other BC 30 owner that I know of who has experimented with tube changes. There may be others out there, but so far I haven't seen their information posted anywhere. He said that the 6L6GC that he tried did not correct the sterility issues with the second channel. It may have just been his choice of tube. I think that this circuit needs a pair of power tubes that are designed like the 5881, but with a higher voltage rating to handle the 410 plate volts that this amp puts out (note: This is as reported by a poster on another site. I have not been able to verify this myself). At least that's the way it would appear given that the Philips 6L6WGB's that I put in have performed so well. I'll do some checking to see if any 6L6GC's out there will fit the needs of this amp. In the mean time hopefully there will be others posting around the web with their experiences.

The tone of this amp has been a surprise to say the least. While I was expecting tweed or brown face tone, this amp delivers something more in line with AC30 tone (at least on channel two).

[duhvoodooman***]

I love it when a plan comes together...!

Wow, it sounds like your new Epi Blues Custom 30 really came to life after the tube change! Glad to hear that, because your initial impressions made for pretty discouraging reading. After Epiphone did so many things right with the BC30, it's a shame they would handicap the amp like that with inferior tubing. You were fortunate enough to have the right NOS tubes on hand to cure its ills, but what is Joe Average Guitarist to do? I wonder if an appropriately selected set of JJ's from Bob Pletka would hold similar benefit? You might want to consider shooting him an e-mail with your findings, so he can get a jump on identfying a Blues Custom Retube Kit like he offers for so many other amps. Based upon your experiences, I suspect there may be a lot of new BC30 owners--at least those with discriminating ears--who aren't going to be happy with the stock tone and will be looking to make an upgrade. And $200 worth of NOS tubes probably isn't an option for most of them!

In any case, thanks for sharing your experiences with all us Fretters, and all the time you put into these very informative postings. Sounds like you're going to have many well-deserved hours of pleasure playing through your "Bloozified" BC30!

[Bloozcat]

Well, I haven't given up on the reissue Tung-Sol 5881's just yet DVM. I've been reading of some usages of 6L6WB's in the 450 Volt range. The 5881 was originally designed as a ruggedized 6L6WB, so maybe the new Tung-Sol has some promise yet as well. There are other 6L6 types to consider also. The highly regarded Shuguang Shortbottle Blackplate 6L6WGC was some real promise. At $35.00 a matched pair from Lord Valve, they're affordable. Before the emergence of the reissue 5881 Tung-Sol, this tube was the "go to" tube for all "true" 5881 applications (old tweeds and brownfaces). Add to that the Tung-Sol 12AX7's and anyone can afford a tube change - with NOS quality level tubes. I'm just perplexed though, as to why Epiphone chose such a poor tube as the Sovtek 5881. Surely it had to be more that the ridiculously low price of the tube ($22.00 a matched pair). Maybe it was their desire to say "5881 output tubes" in their advertisement.

I was pretty fortunate to have had on hand both the Philips 6L6WGB's and the Philips 5AR4...as well as some "left over" NOS pre-amp tubes. I actually bought the Philips output and rectifier tubes about two years ago in anticipation of buying/building a tweed amp at some point in time. I knew they wouldn't be around forever, and that the price was going to skyrocket at some point, so I bought while the prices were "reasonable" (everything's relative). Fortunately for all of us there are people like Mike Matthews at New Sensor who not only saw the handwriting on the wall, but acted upon it as well. I think the reissue Tung-Sols and Mullards that they market are just the beginning of what's to come. Soon, NOS will be just be the territory of a few quirky audiophile types and museum curators. Who knows, maybe in a couple of years we'll be talking about a new "golden age" in vacuum tubes. I'm hopeful....

[Nelskie]

In any case, thanks for sharing your experiences with all us Fretters, and all the time you put into these very informative postings. Sounds like you're going to have many well-deserved hours of pleasure playing through your "Bloozified" BC30!

Blooz - I also share DVM's appreciation for this very interesting and informative thread. Your extensive knowledge of tubes and tube amp circuitry, combined with your literary savoir fare, is an absolute joy to read. Hopefully, you'll soon cross that diamond with a pearl in regards to your BC's tube combination. As always, we all look forward to hearing about it. Keep up the great work!

[Bloozcat]

Thanks guys...

Your kind words are most humbling. I feel as though I know nothing next to others out here in cyberspace. I only hope that I share with others as many have shared with me. I'd know nothing if not for the time that others have spent in educating me. I guess that's what keeps me going...there's so much I don't know, but want to know. And what good is knowing if there's no one to share it with?

I think that everyone here has something to offer, and all share what they know with enthusiasm and great humor. That's what makes this site so great.

[duhvoodooman***]

I'm just perplexed though, as to why Epiphone chose such a poor tube as the Sovtek 5881. Surely it had to be more that the ridiculously low price of the tube ($22.00 a matched pair). Maybe it was their desire to say "5881 output tubes" in their advertisement.

I suspect that was it, exactly. Give it a bit of that "vintage" cachet with the rectifier tube and the 5881's.

Soon, NOS will be just be the territory of a few quirky audiophile types and museum curators. Who knows, maybe in a couple of years we'll be talking about a new "golden age" in vacuum tubes. I'm hopeful....

I think that's a plausible scenario, BC. As NOS tube supplies dry up, a couple of things are happening, neither of them good:

• Obviously, by the law of supply & demand, prices go up. NOS tube prices are already beyond what most tube amp owners are willing to pay, and it ain't gonna get any better! And more & more of the NOS "legends" are no longer available at any price!
• Buying NOS tubes is getting riskier & riskier. Charlatans continue to spring up on the web at eBay and elsewhere, hawking NRCTN (not remotely close to new!) tubes as NOS, or selling blatant counterfeits. And genuine NOS tubes of questionable quality get sold because the financial incentive has gotten so high.

What it all boils down to is an attractive commercial opportunity for savvy entrepreneurs like Mike Matthews. The demand is obviously real, with amp owners willing to pay a premium price for NOS-quality tubes. Since so much of what's coming out of Asia and Eastern Europe is clearly of inferior quality relative to the much tighter tolerances that NOS tubes were held to, tube suppliers who can fill that void stand to make a mint! Mike obviously recognized that, and I have to believe there will be more like him. JJ has taken a strong step in that direction, but from some of what I've read, they're still a long way from the tube-to-tube quality and consistency of the best NOS tubes. It will definitely be interesting to see how all of this develops....

[Bloozcat]

The big variable in this new tube market is the Chinese...specifically, the Shuguang factoy. All of us who own the Epi Valve Jr. and now this BC 30 can attest to the build quality of these Chinese made amps. The Shuguang tube factory is starting to turn out some very, very good tubes. The build quality is now such that some models like the 6L6WGC is so well built it looks like an American made tube...and that's from Lord Valve who's seen a tube or two in his time. A little direction from someone in the west could put them in a position to compete directly with New Sensor's Tung-Sol and Mullard offerings. That competition could only be good for us at the retail end.

Time will tell, but at least there are alternatives emerging to save us from expensive NOS tubes. Heck, the next batch of pre-amp tubes I'm going to buy will be the Tung-Sol 12AX7's at $16.00 ea. That's a whole lot better than $30.00 a tube for NOS, and these Tung-Sols sound every bit as good as an old RCA Blackplate ( I like LV's description of them..."audio crack" ).