A Look Inside Fender’s Excelsior
This is a preliminary page for Fender’s Excelsior amp. The Excelsior will benefit from some mods and upgraded components.
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Here’s a look inside the Excelsior, the left (looking from the back of the amp) side of the power section. Apart from it’s “pawn shop” vibe, the Excelsior is modern inside. It includes an NTC thermistor to control inrush current and the full wave bridge diodes are individually bypassed by noise suppression capacitors.
The two large white sand-cast resistors are “sag” resistors, to simulate a tube rectifier. In addition to the main fuse, there’s a heater fuse and a soldered-in plate supply fuse on the output tubes.
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This board feeds the output tubes. They’re cathode-biased, as you might have guessed from the 13 watt output rating. The sockets are ceramic. The output jack is rather inconveniently located behind the output transformer.
The flexible tube that connects the preamp chassis to the power chassis is standard, electrician-grade stuff. The tube is steel.
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In the preamp chassis, the input voicing is done right on the jack board. There is no voicing on the guitar input, padding (reduced signal) on the mic input, and a fairly heavy treble cut on the accordion input. The mic input is somewhat like input 2 on a typical guitar amp: twice as much resistance, but unlike most Fender amps, it retains high impedance on the mic input. The accordion input is capacitor-coupled, which cuts signal strength and attenuates frequencies. I found it fairly useless for guitar.
The signal goes through the ferrite at the left to eliminate RF noise. Since there are only two amplification stages, they’re very high gain. Fender chose 220K plate resistors for the gain, plus a high value for the first stage’s cathode resistor. The result is kind of un-Fender-like.
The volume control and tone switch sit between the two stages. “Dark” is a heavy treble cut. Bass is the same at the Bright or Dark settings, but Bright activates a treble bypass cap that boosts highs. The contrast is too great between the two settings; this amp definitely needs a tone control.
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The tremolo circuit is a conventional low-frequency oscillator that varies the grid bias on the output tubes. The tubes are cathode-biased, but there’s a combination of grid- and cathode-bias when the tremolo is active. The power transistor on the board is a MOSFET that drives the grids. The phase inverter is a conventional cathodyne circuit, much like that found in the Princeton Reverb or Tweed Deluxe. The signals go through individual, shielded wires to the grids of the 6V6s.
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The sockets are attached to the chassis and the 12AX7s are shielded. The amp is equipped with Chinese 3-mica tubes, which aren’t too bad.
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The underside of the panel is straightforward. No circuit board-mounted components except the input jacks. Lots of room for mods!
Overall, the Excelsior is a loud amp and even with the two high-gain stages, it’s uncomfortably loud for home playing before you get crunchy distortion. It’s going to need some modification to allow distortion at more reasonable volume.
Modification Potential
The Excelsior has pretty strong mod potential.
I’ve already tested it with a one-knob tone control that uses the stock bright and dark settings as its upper and lower limits. I’ll be offering it as a kit. The control itself is the easy part. The harder part is a good-looking faceplate that covers the screw holes and slot. The slot also requires some filing to clear the shaft of the tone control.
I’ll also have a kit for a tremolo on/off footswitch.
The stock 12AX7s are not too bad for inexpensive Chinese tubes, but feel free to experiment. The stock 6V6s are just adequate. I prefer JJ 6V6s because the large plates improve bass response and they sound better overall. A better output transformer will help, but an upgraded speaker is a better investment, at least at first.
The stock speaker is not particularly efficient and has a characteristic tone that dominates the amp’s overall tone. An Eminence Legend 1518 is far more efficient–louder, with more consistent tone, better bass. It’s probably the most cost-effective 15-inch speaker you can find, too.
The Excelsior is clean at moderate volume. The best way to get overdrive tone at low levels is with a pedal. There may be other ways to get more gain out if it; I’ll post more as I experiment more.
Here’s a video of my Excelsior with a single-knob tone control, with and without the Eminence Legend 1518 speaker:
My take: The tone control really helps tone down the treble harshness. The Legend 1518 has classic tone, greatly improved lows, and a much more refined midrange. It’s also dramatically louder than the stock speaker.
Billm,
I just finished changing the Excelsor speaker to the Legend 1518, and the tubes to the JJ6V6 power tubes. I put in the JJ high performance 12AX7 preamp tubes. I probably should have gone with the standard JJ 12AX7 for the harp, but I wanted volume. 3/4 volume is way higher than full volume was before the changes. I start getting feedback at about 3:00 oclock on the volume when playing in my living room – a veritable feedback chamber with hardwood floors and nothing to absorb any sound. I plan on getting a Lone Wolf harp shield pedal which will solve any feedback problem.
In my living room, 3/4 volume is now way too loud. Anything close to full volume there is gonna make my ears bleed. I still have the Excelsior tone, just clearer and louder. I don’t use a green bullet type mic cause I’ve just got one hand, and have trouble cupping one. The mic I use is a Shure Beta 58A which has a lot less feedback than a crystal mic, and I like the sound better.
Long story short it took some time to make sure I didn’t screw anything up. I’m not electrically inclined at all. I can barely change my own lightbulbs – just kidding. But it wasn’t hard at all, I was just slow and careful. I had my boy plug in his guitar and play a bit. It sounds absolutely awesome. Fabulous change in the volume and clarity. I don’t need a line out or an earbud. I’ve got enough volume to solve both problem. Taking it a gig Saturday. I’m betting I’ve got a new sideline tweaking Excelsiors for a few buddies once they hear this thing. It’s hard to believe this is only a 13 watt amp. Awesome Awesome amp with these changes.
Thank you, for me this is now the perfect harp amp.
Jimbo
I got my Excelsior a few days ago. I changed out the stock pre amp tubes to some JJ ‘s and I think the sound is better but I swear the hiss is louder when running it towards the top volume any thoughts on that or is it just a side effect of the different tubes. I will be putting the new JJ 6V6′s in when they arrive. I hope to change the switch to a tone pot, possibly move the speaker output to a better location, increase the wire gauge for the connection to the speaker ( does that matter )?
thanks
Larger wires won’t make a difference. It’s only 13 watts.
Some tubes hiss more than others. Sometimes it pays to try different ones, even if it’s a hassle to send the noisy ones back to the vendor.
Actually it was just the difference between the dark/bright setting at higher volume, good bit more noise on bright as you might expect. I play a Les Paul and on the dark setting, the bridge pickup sounds good and the noise is acceptable even with a distortion pedal. I got a copy of the schematic today and I am thinking that the cap values change to slow down the tremolo speed range ? I think you are putting together a kit for tremolo switching, could you use the accordian input jack, disconnect it and use it for the footswitch connection to save drilling a hole ?
I think I commented earlier that it’s impractical to use one of the input jacks for a pot. There isn’t much room and there’s a circuit board behind the jacks. It would have to be cut and everything rewired.
Has anyone considered pulling the 15″ and seeing if there is room for a dummy board and use a 12″ instead ? Would it push the spkr frame out into the chassis ? Just wondering how it would sound with 1-12″ , I think the spkr options open up a little once you get away from the 15 ” ?
I did this, with great results. I made a new quality baffle and used a Celestion G12H30 installing it a little off center. I also tried a C Rex but liked the sound of the G12 better, however both speakers had similar results: The amp became very clean with a lot of head room and LOUD! I should note that I did a tube upgrade as well, installing JJ6V6′s and Tung Sol 12AX7′s. I also did the tone control mod. The Excelsior is a great platform for tone shaping.
what is the actual tone control mod? do you wire up a 500k linear pot to the 3 wires that currently are on the hi/lo switch , and physically remove the switch ? Also, can you replace the on/off pot for the tremolo with a non switching 500 k and use a remote footswitch ? Anyone figured out how to slow the tremolo down yet ?
You need an audio-taper pot, not linear, or the treble comes in way too fast.
The tremolo control is 1M. There’s no point in replacing the control if you move the switch to a jack. I haven’t tried it; the switch is tied into the oscillator and may change the reliability of the circuit. You could try reducing the size of the 100K resistor between the trem pot and ground to slow it down. Or increase the size of one of the .02 capacitors slightly.
Do they make any slider controls that you could install in place of the switch?
You would have to use a nibbler to lengthen the slot for a slider. I imagine it would look pretty messy.
what s the actual jack you would use by switchcraft that is the correct configuration inside to use with a regular footswitch, and is also insulated from the chassis when you mount it ? I will leave the 1M pot and will probably add a temporary 100k pot and experiment to get the “right” value to slow the trem down, then replace with a fixed resistor. I am not looking at the schematic – which side gets grounded ? Do you have a suggestion for a little more intensity for the trem ?
Sorry, I’m so busy with Blues Juniors right now, I don’t have time to dig back into the Excelsior schematic. But the answers should be there when you look at it.
I see which resistor , you mean the R37, thanks
Hi Bill, I ordered the Fender Excelsior, and being the lunatic I am, I also ordered the Eminence 1518 speaker, and matched 6V6 and 12AX7 tubes. I plugged it in to make sure it worked when I got it delivered, then took it apart, installed the speaker, and the tubes. When I plugged it in, I heard a hum, then a pop, and now I got Nothing. The tubes still light up, and there are no burn marks inside on the circuit board as if a resistor blew up. Plus the fuse hasn’t blown… I’m at a loss…
BTW My heavilty modified Blues Junior is still kicking butt, thanks…
Maybe you should just put the stock stuff back in and return it. There are some internal (soldered-down, not glass) fuses. One of them may have blown.
An internal fuse blew, probably when I installed a tube the wrong way. New fuse, new JJ Tubes, and new 1518 speaker, this thing sounds incredible… For the price it;s worth it…
Thanks
Hello Bill, I found you on you tube. I was looking for info about the Excelsior amp. You did a nice job on that video. My Excelsior has some tube rattle in higher gain ranges, so I found your comments comforting. It’s probably endemic to the character of the manufacture both in quality and design. I’m not alone after all.
I love a 15″ speaker so I’ll source up a Legend and throw it in there. Do you think your new three position ‘standby’ switch mod will work on the Excelsior Pawn Shop Amp ( EPSA )as a replacement for the standard on/off switch ? And another thing, is that bright / dark switch mod you did, done with a standard potentiometer / tone control arrangement you can supply? And are you ready to supply or still overwhelmed. We all understand Hurricane Sandy wasn’t a nice girl. How are you holding up? Here in Portland, Or the only hurricanes we get are at the bar and in a glass.
The standby switch is a possibility, but it’s not as straightforward as it is on the Blues Junior. It will take more design work to create an easily installable kit. I’m not quite ready to begin Excelsior mod shipments. I have to hire a new assistant to free me up for design and sourcing the components. Working on it….
Voila, The EPSA ( Excelsior Pawn Shop Amplifier ) has the new tubes, matched duet JJ’s 6V6s for the power section and two JJ’s 12AX7s for v1 and v2. BIG difference on this amp. Significant reduction of Harsh, and increased clarity in all tone ranges. Suddenly this amp is more ‘smooth’ and ‘more musical’. Good Fun. Next up will be the Eminence Legend 1518 when it arrives. Comon’ UPS . BTW this amp is showing promise as a Honky Tonk Swing Jumper Bluesy Baby. It’s got an old feel to it. I’m playing a PartsOcaster, alder body and a set of Lindy Fralin ‘vintage hot’ pups. Plenty of growl when needed.
Bill, you are right on with comments about the bottom end, it’s just not there. Opportunity looms again. I’ll see what happens with the speaker change out, but I suspect there’s more to the story……
Hi Bill,
I bought my first Excelsior 2 months ago, but it went back because it had an annoying buzz, not really loud, but noticeable. So I returned it and the store got me another one, and while this one isn’t as bad, it still buzzes, actually more, but only on D notes.
I wanted to ask if you (or any other user, for that matter) had any experience like mine, and how did you solve it. I know that changing the tubes would be an upgrade, but I don’t want to spend any unnecessary money on an amp that, if continues like this, will go back.
The other thing that I wanted to ask is if you have any experience with Fane speakers, particularly the SOVEREIGN 15-250. Most people is replacing the stock speaker with the 1518 Eminence, but I think that’s expensive, especially considering the price of the amp itself.
Thanks in advance, and congratulations on the site!
Hi there,
I have strange buzz (or hiss) in my Excelsior too. I tightened chassis screws, put some extra damping everywhere and made sure that new Eminence 1518 is aligned properly etc. Then I finally found out this very annoying noise coming from preamp tube sockets. Quality of sockets is really not so great and I already ordered new ceramic sockets.
As I get this issue resolved, it will sound great again.
Hello Bill,
The FedEx guy came to my home today and delivered the ebay supplied Eminence Legend 1518. Well, I already wasn’t workin’ today so I tossed the EPSA onto the bench and got into it. Nip and tuck, I recycled the speaker wiring and soldered it onto the speaker lugs. The white stripe was on the left lug so I remounted it the same way. Next I mounted the new speaker into the cab. Your wisdom became immediately apparent as the holes in the frame of the speaker were precisely aligned with the originals. This was great that Fender chose tee-nuts and machine thread screws for strength and long service. Of course not every speaker frame will line up and fit perfectly but it’s easier when they do. A bit more re-assembly and it was time to plug in.
This gets it’s own paragraph. Pros : W O W ! It was so different I had to go back and re-view your video. I wanted to review all your tech data and opinions to see where I went off the deep end. First off, I had no idea 10db was so loud. Second, now have 400% of prior bottom end. Farty no more, dynamics and sensitivities are enhanced. Really. Insta-sonic upgrade is obvious and clear. Cons : without a tone control, this amp will never be up to it’s potential, bright hiss is more pronounced yet not manageable. A rotary device is needed. Verb? What to do? For temporary I went to a local music store and A-B’d a bunch of verbs and selected a t.c.electronics ‘hall of fame’. Seemed lush, smooth and it has 10 different voicings.
Lastly, I, too, get a solid microphonic feedback/noise on the A string around D and Db. Not the open D. Just on the A string. Sympathetic Resonance, reminds of a girl I knew
………….
Are there any plans to add a reverb tank? Tanks cost much less than a reverb pedal, and will certainly sound better as well. We are running out of real estate on the control panel though, so maybe a push-pull switch could work with the tremolo knob. Are any tech wizards interested to try this?
The tank alone won’t do it. You need a driver circuit and a recovery circuit, too. It requires a circuit design, power supply, and some decisions about where to put it in the amp stages. And a reverb level knob. On/off isn’t enough, at least not for me.
Hi. Brilliant video thanks! I was wondering, and by the way I’m not very technical so I’m struggling as it is, but will any 15w 15″ 8 ohm speaker do the trick when it comes to replacing the stock speaker in my excelsior or not? For instance a Celestion Eight 15 or an Eminence Big Ben or is it just personal preference as regards tone, etc?
Thanks! Mike.
I went with loudness and tone that I thought was most appropriate for the Excelsior. But any 15 will work. You just don’t know how loud or what tone until you try it.
Hi I’ve noticed that if you put the trebble swich halfway low and hi ,that it works a little like a pot meter grtz
Hi. I will be the new owner of a modified Excelsior later today. The person selling it has already had the Patriot speaker installed, and the tubes upgraded per your suggestions. LEss work for me. My question is, when will you be offering the tone knob kit for sale, and you mentioned replacing the OT. Can you recommend one, do you offer one? I am looking for a amp that has a lower break up than my bassman 59 reissue. i know with or with out the mods, the excelsior is still a bit loud for house breakup. You mentioned that there may be other ways to tame it other than pedals. I was hoping for an amp that broke up by itself.
Thanks for all your work in making these amps crank!
Just a follow up, I got the amp. It sounds night and day different from the stock one. However, for a guy looking for a lower breakup volume, this is not the answer. The amp is actually louder, although crisp and clear and full. So, I like it either way, and am interested in the mods mentioned above. Thanks!
If you replace R8 (480k) with a 500k pot would that allow you to adjust the “width” of the tone switch making it less extreme if desired?
Yes, it lets you blend the high and low tones.
Hi. I got an Excelsior for Christmas. It sounded great till today when it turned on and had no sound. Tubes have power. I tried all 3 inputs and nothing. I may delve deeper just thought you may have a thought.
Sorry it stopped working. Take or send it back.
Hi. Did you get the problem resolved? What caused it? Something similar happened to mine this evening mid gig – the power just disappeared. Not certain why. I’m taking it back tomorrow. Only had it two days.
Can I just use a y cable to put another 8 ohm speaker from the amp, to double my sound with the excelsior?
Is it something you have a kit for?
Thanks!
You can use a Y cable. It won’t double the sound. It will be about 3dB louder, but a broader sound stage.
Happy New Year Bill! Thanks for all the great info on the Excelsior. I’ve had mine for a few weeks and while I love the amp, I’m looking forward to doing some of the upgrades you suggest.
Are you planning to offer the tone control as a mod kit? I hope so.
Thanks again,
-how
No plans yet. I’m still too busy with Blues Juniors.
I read somewhere that the dark/bright switch can be jumped in the middle, like the way we used to get the quck position in a strat. I tried it and it seemed to work, but I would rather a better solution. Have you considered a 3 position switch, giving a blend of the two settings. The mod would be invisible but offer another great setting?
I too, am curious about using a 3 position slide switch to achieve the combined sound. I have installed a 500K pot to replace the switch. It works OK but I still find myself turning the tone control full up and using the tone control on my guitars to tame the highs. Also, is it not true that when you install a pot in this circuit it will slightly reduce gain? If so, I believe that, theoretically, the 3 way slider switch would not have any effect on the gain. I know that I can figure this out myself, but to make sure I am correct, How would I wire the 3 way slider switch.
There’s no difference between a pot and the resistors in terms of tone. The pot just makes some of the resistance variable.
Hi Bill, thanks for all the info here. I’ve just modded my excelsior with an Eminence Legend and a tone pot, sounds much better. However I just put new tubes in (TungSol 12AX7′s and JJ 6V6′s) and there is now an appreciable hum which wasn’t there before, any ideas?
Cheers
Matt
Put the old 12AX7s back into the amp to see if it goes away. You may have a defective tube.
Hello Bill,
Is the jewel light replaceable?
No, not replaceable other than by pulling out the assembly and putting in a different one. The LED is red, so you have to change it to white in order to run a different color anyway, as we do on Blues Juniors.
My Excelsior rattles too. I changed out the tubes to a new set of JJ’s and that didn’t solve the problem. After investigating the back of the amp while playing it appears the rattle is coming from the speaker magnet. Tap on the magnet and the rattle appears. Have you run into that before? Maybe upgrading to an Eminence Legend 1518 is the solution.
Hello Mr Bill,
I have a quick question for you. I just purchased an excelsior and I am for sure going to be adding a tone control to it. I was comparing the schematic of the Pro Jr and the Excelsior and I was wondering about clipping out R9, R8, and R29, and just connecting lug 1 and 3 of the 500K tone pot to C2 and C19? That would look a lot more like the tone control on the Pro Jr. Is this a good idea, or bad idea? Thanks!!
Levi
I haven’t spent much time inside Excelsiors these days, too busy on Blues Juniors. I’ve never been all that impressed with the Pro Junior’s tone control; it may not be the one to emulate.
No progress to report.
Hi,
Is it possible to replace the original OT by TP26 in order to use JJ6L6
Do j have to order the power transformer too
Any other modification to do ?
Thanks a lot
Philippe
Yes, the TO26 will provide the correct output impedance for 6L6s and will improve the bass. But you will not have much more power with the stock power transformer. The TP24 power transformer is not available for 240V mains.
Hey Bill,
Is a master volume possible? I love the sound of the Excelsior broken up a bit but I live in a condo so it’s pretty much an impossibility to turn it up. I love the tone control by the way.
Jim
There’s no easy way to add a master volume to the Excelsior.
Hi Bill,
Just got an Excelsior and, like Jim, I’d really like to use the broken-up tone at lower volumes. Would it be possible to put a volume control before the speaker jack for the built in speaker?
Your site is fascinating reading for a tube amp newbie.
Thanks,
Simon
An attenuator is the proper tool if you want cranked tone at low volume. See the Weber site for some reasonably priced ones.
Thanks a lot!
I’ve ordered the 25W load dump. It’s not quite double the power of the amp, but should be sufficient for my use. I’ll let you know how it sounds when it has arrived.
Got the load dump a week or so ago but hadn’t realized how hard it would be to get the speaker cable where i live (rural Japan). Finally got it wired up today and I’m very pleased. It does the job for late night practice and sounds much truer to the amp’s sounds than using my zoom effects pedal for overdrive.
Thanks again for the advice.
How about a switchable bright channel mod similar to the bright channel on a Fender tweed amp? By replacing the volume pot with the same value push pull pot and being able to switch in a 100pf cap across that pot.
I find that when using my blackface amps (In which I have replaced the 120pf bright caps with 100pf caps as per tweed specs) I sometimes turn down the treble control and activate the bright switch for a different high end response. Would this not work well with the Tone Switch and even better with the tone control mod?
I bought my Excelsior three weeks ago. Very first I replaced speaker to 1518 Legend and power tubes to JJ’s mathced pair – like almost everyone here. I had some rattle issues as well, but I only had my power tube “cage” litte loose and also cover of power amp rattled a little before some extra damping and tightening screws.
However, I did not replace the bright/dark – switch (yet). Has anyone tried 12Y7 at V1-position in pre-amp? Excelsior is really loud enough, so I thought loosin’ some pre-amp gain won’t hurt (?)
I have used 12Y7 at my -72 Fender Quad Reverb’s position V2 (Rev/Trem-channel) and I think it sounds just great. Quad Reverb is equipped with Eminence Texas Heats.
Anyway, I love the simplicity of Excelsior and even after extra 9 lb:s from Legend – it’s still quite portable (at least compared to Quad Reverb…). With Landgraff OD -clone the sound is just a killer with Telecaster and also with Les Paul (P90′s). As soon I have tested 12Y7 in Excelsior, you will hear from me again.
Ok – 12Y7 (EHX) is now at V1-position and JJ ECC83S at V2. Matched pair of JJ’s is still in power section.
First impression is good, tube noise was clearly reduced, especially with single coils – I had Tungsol 12AX7 at V1 first.
With Legend 1518 it’s still loud enough and sound is just right for me. Still using only “Dark”- setting of the tone switch and I think I just leave it that way.
I, too, like the 12AY7 in V1. I have the stock 12AX7 in V2 and Tungsol 6V6s in the power. I’ve done the “Smooth Chocolate” tone mod (http://bit.ly/XO7R5L) from Alnicomagnet. Great results! Still stock speakers.
I have a Mercury Magnetics Out put transformer arriving Monday. Any tips on the install? Have you tried this yet? My understanding is this is one of the last mods this amp needs to get to where it can be. I have already done the speaker and tubes. Not sure if I will have the tone mod done, as I like the tone cut.
The tone of the Excelsior is shaped and bottled up in several other places. I haven’t heard any output transformer that made a big difference.
I managed to get the OT in. Its a bit bigger than the stock one. Had to drill another crew hole, but the wiring is exact. Had to solder two wires to the speaker jack, the other three got crimped back to where they go. I can say that the amp is over all considerably louder. Prior to the tubes and speaker, it broke up easily at 4, but sounded farty, if thats a good tech word. With the new tubes and speaker, it had a fuller sound and was louder, and broke up around 5 or so. Now I need to turn it to 7 to get the same break up i had prior. This means a lot more clean head room. I can cut through a drummer no problem. I use a preamp to get break up at lower levels, and this thing sounds great! Would never had done these mods had I payed full price for the amp, but I got it really cheap with the new tubes and 1518 in it. For what its worth, it dont sound like a stock excelsior by any means. Its also very heavy! I re tolexed it, and took off the emblem. I now call it Bob! Thanks for your work and help! Many peolple come here for info on your mods!
Hello, I’ve been looking through the comments on here with great interest, I’ve had my Excelsior for about a month and other than putting some tilt back legs on it I’m yet to do any mods as such.
I was wondering whether anyone had tried putting a 5751 valve into position 1 and what effect it had?
I also tried a trick on the amp I’d seen many years ago, I inputted the guitar in the first input then looped another lead between the mic and accordian, it seemed to boost the tone/volume? not really sure what I’d done though, or indeed whether I was causing any harm to the amp?
Jumpering the mic and accordion inputs might give you a lower input impedance, which would change the tone somewhat. But it’s only a single-channel amp with three inputs to that channel, so it can’t do much. And it can’t hurt anything.
What about the FSR Excelsior Pro? Besides an upgrade to 15″ Eminence Legend and change of colors (Sonic Blue – Antique Blush – Surf Green) it seems to me like the first edition, but claimed to be only limited. But that’s also said before with the Blues Jr. Here in Europe there’s quite a price difference between the two ($355 vs $440). I looks like a Pro is worth it if you don’t care about looks and low on budget for a 15″ speaker (1/3 of the Excelsior price) upgrade for the first version. Still options for future mods.
Bill,
I did the Excelsior tube and speaker swap and love the tone and volume I get for harmonica. I recently swapped to a Microvox mic. I was using a Shure 57 or 58. Microvox is high impedence and very hot. Its mic is about the size of a Bic pen cap. I don’t have the eguipment to test it’s output, but I like it because it sounds great on harp and I have one hand so it allows me to cup the mic and close the cup with my stump for a cupped sound. I use the guitar input because of the mic’s high impedance,
My problem is feedback with the hotter mic. I ordered some different preamp tubes to experiment with to drop the gain a bit.
I ordered a pair each of: 5751′s, 12AY7′s, and 12AU7s. I also might try a pair of 12DW7′s. Will swapping any of these into the Excelsior hurt it? Also, do both preamp tubes need to be the same, or can I use say 5751 in the first preamp and a 12AY7 in the second preamp.
On another site, someone said something about keeping the 12AX7 preamps and clipping out the C7, what ever that is to reduce feedback. What’s the C7 and what does clipping it out do. I know an amp builder and customizer who could do this for me if doing it makes any sense.
Thank, Jimbo