Barley Nectar
647 posts
Feb 13, 2015
11:19 AM
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OK folks, I'm wanting to build an amp for a cool new /old cab I picked up recently. What is the #1 Masco amp for harp?
Will be looking for the schematic once this is determined. Thanks Folks...BN
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Kingley
3839 posts
Feb 13, 2015
11:37 AM
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The one that people seem to rave about the most is the MA-17 from my observations.
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HawkeyeKane
2708 posts
Feb 13, 2015
11:41 AM
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The Megatone WEZO ME-18 is based off the original Masco ME-18. 30W powerhouse.
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Hawkeye Kane - Hipbone Sam
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shakeylee
94 posts
Feb 13, 2015
11:43 AM
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I have a 1947 MA-47 . I like it a lot. Some of my values are changed and sometimes I run it with a SS rectifier ,sometimes tube .
It is versatile and you can cater the cabinet to the venue.it is a pretty loud 2x6l6, but not crazy loud.
Some people prefer the smaller practice amp sized ones.
If you are near Philly, you are welcome to come play it.
Somewhere I have a hand drawn schematic with the changes made .if I can find it,I'll copy it for you
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Www.shakeylee.com
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shakeylee
95 posts
Feb 13, 2015
11:45 AM
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Oops,I meant MA-17
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Harpaholic
610 posts
Feb 13, 2015
11:57 AM
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As you know there are so many Masco's good for harp with the right mods.
I'm partial to the Masco's with full tone stacks like the medium wattage models
I've owned all the popular models up to the 50 watter, but my Audiosphere 36 is better than all of them.
Keith Robb modded it the same as the 36 he built for Charlie Musselwhite a few years ago but took it even farther with a couple extra mods for guitar, an AC cut switch and a DC cut switch. The phono knob is a gain control for all the channels. There's so much going on in this amp too list.
It's a monster amp for guitar and harp. I've used it on stage with a 2x10 cab in a loud band and it cut like a knife with no feedback issues.
I've bought and sold close to 100 amps in the last 13 years, this is one I will never sell!
If I were doing another Masco, I would look for a ME-27, but I'm assuming you've made your decision already.
Keep in mind the model # doesn't mean the actual wattage. My 36 produces 24 clean watts with original trannies.
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Harpaholic
611 posts
Feb 13, 2015
12:03 PM
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The ME-18 is my 2nd favorite, but it's not 30 watts from the factory, probably 16-18?
I would go with the ME-27 because more wattage and tone stack.
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HawkeyeKane
2709 posts
Feb 13, 2015
12:05 PM
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"The ME-18 is my 2nd favorite, but it's not 30 watts from the factory, probably 16-18?"
Sorry....I meant the Wezo ME18 is 30W.
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Hawkeye Kane - Hipbone Sam
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Barley Nectar
649 posts
Feb 13, 2015
2:44 PM
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Shakeylee. I'll take that schmo if you can find it. Nothing on the web which is surprising considering how these amps are talked up...BN
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shakeylee
97 posts
Feb 13, 2015
2:56 PM
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I am also trying to find the builder's name!
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Barley Nectar
650 posts
Feb 13, 2015
4:44 PM
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Don't worry about his name. I am an experienced builder. The guys at Lone Wolf and Weber VST taught me the ropes years ago. I am lucky to have gotten their help. I enjoy working on and restoring old tube amps. Great hobby...BN
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TetonJohn
240 posts
Feb 13, 2015
6:19 PM
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FWIW, it's good to know (in terms of a schematic) that the Skip Simmons' re-builit MA17 that folks rave about is not stock; I don't know what he does, but he voices some for guitar and some for harp.
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shakeylee
98 posts
Feb 13, 2015
10:06 PM
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ok,have not found the schematic yet.
i know you said you didn't need the builder,but just in case someone in the finger lakes area does,He is John Ward, in Canandaigua, NY. does great work
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Barley Nectar
652 posts
Feb 14, 2015
9:22 AM
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Hey, don't kill yourself. It's no big deal. I'll come up with something. Thanks...BN
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jimr
77 posts
Feb 15, 2015
8:24 AM
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The question of suitable Masco amps for harmonica depends on if you plan to use it with the original circuit (with servicing as needed) of have it modified.
To me, the original circuits that are good are those with a pentode single gain stage into a paraphase phase inverter. These include the ME18, Audiosphere A17 and MA17 heads as well as MU18 combo (MU18 has channels with both pentode and triode first gain stages). The larger Masco heads typically have an additional gain stage and these are more feedback prone and not as sweet.
I have examined a Simmons Masco. This amp originally had an octal pentode preamp tube but was changed to a dual triode. This is a major change. I imagine that if you plan to have a Simmons or some other expert rebuild, the original circuit does not matter as much as it will be changed.
The bigger Mascos have different output and power transformers and operate at higher power supply voltages. I don't know if a Simmons Masco ME36 sounds much different from a Simmons ME18. I built a high voltage version of the ME18 circuit and it was excellent.
The Sonny Jr. original 4x8 amp circuit is very similar to the Simmons modified Masco I examined, and different any Masco head I have seen. The Masco MAP 15 and MAP 120 combo amps do have all triode preamp tubes like the original SJ. The MAP 15 sounds good but the MAP 120 is disappointing.
Jim Rossen
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Barley Nectar
653 posts
Feb 15, 2015
10:29 AM
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Hi Jim, This is Goose. You know me from the Weber board. This will be a scratch build to which I will mod as seems suitable. Using an old Victor 1x12 cab with the original alnico smooth cone of unknown origin. Cab is beautiful and speaker is sweet. I will not be using an original Masco chassis. As an accomplished builder I value your input. A circuit with a 6SJ7 as V1 would be just the ticket. Masco MA-17 seems to be the overall favorite of the harp community. I am looking for the schematic to use as a starting point for this project. I do have the ME-18 schmo in front of me. Would like to do some comparison of these circuits. I'll google that Audiosphere A17 also. I believe there is an MU-18 combo on Ebay now but not going that route. Thanks Jim, good to hear from you...Goose
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Harpaholic
624 posts
Feb 15, 2015
10:39 AM
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Barley its actually an Audiosphere A-18, but you may have figured that out?
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Harpaholic
625 posts
Feb 15, 2015
1:20 PM
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"The larger Masco heads typically have an additional gain stage and these are more feedback prone and not as sweet".
Keith bypassed one gain stage on the A-36 he did for me and Charlie. I don't agree there not at sweet. That all depends how far you go with the mods.
I have the ability to run mine from 25 watts down to 10 using the AC and/or DC cut switch.
I can run 5V4, 5Y3, or 5U4 rectifiers in this amp. Which all have an effect on tone.
The Phono control is an interactive gain/boost control for channel 1, 2 and phono input which is now a mic input. By raising or lowering the Phono knob, it lowers or raises the gain and sensitivity of the inputs.
Believe it or not, I can dial this amp to sound like an ME18, MA17 or an A-18 and I don't have feedback problems.
Not saying one is better than the other, but I prefer the versatility of the medium wattage Masco's.
Last Edited by Harpaholic on Feb 15, 2015 2:01 PM
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blueswannabe
545 posts
Feb 15, 2015
6:35 PM
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I agrees with jimR. I have the masco 17N. It has two mic inputs and 1 phono input. The mic input has 2 stages of gain but the phone input has only one stage of gain and a paraphase inverter. You want only one stage of gain ideally as Jim states. The phono input has fat tone and you can get the volume beyond level 2. The mic inputs have great tone too but you can't get it past level 2 before feedback. CHeck ebay for schematics and models.
@harpaholic, i have noticed this too but haven't experimented much with it. Using the phono control to reduce the gain of the mic control.
Also, I would agree that with a few mods you can make the amp sound pretty sweet. JimR provided me with some tips on this.
Last Edited by blueswannabe on Feb 15, 2015 6:51 PM
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Harpaholic
626 posts
Feb 15, 2015
6:59 PM
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FYI, the phono control is not stock it was modded to work
that way and interact with all the channels.
Mic 1 is stock, too sensitive for mics, that's for guitar. Mic 2 was like Mic 1, it was changed to allow the most volume before feedback. The phono input was low gain so he souped up that channel.
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Barley Nectar
654 posts
Feb 15, 2015
8:47 PM
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Well, I found the elusive MA-17 schematic. Got a nice copy printed out. This uses a 7C7 loctal( locking base) preamp tube for V1. This is a sharp cutoff pentode and is VERY similar to the 6J7, 6SJ7, EF86. So much so that I may try it with the 6SJ7. I may have the 7C7 tube but not the socket. Cool stuff..BN
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jimr
78 posts
Feb 16, 2015
5:28 AM
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There are at least two versions of the MA17. I have seen chassis with octal as well as loctal socket preamp tubes. A major difference between the MA17 and ME18 is the former has a choke. For a new build, I'd use a 6SJ7 for first gain in pentode mode. A 6SL7 would be good for the PI as it can be swapped for a 6SN7 if less gain is desired and is currently in production. I don't think there is a lower gain sub for a 6SC7. I'd use a choke. I like a loud and hi fi speaker for amps like this. I use Peavey Black Widow steel guitar speaker.
Jim R
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TetonJohn
241 posts
Feb 16, 2015
8:14 AM
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Just FYI, my Skip MA17 has 7C7 and then 7F7 stamped in red on the chassis. The actual first tube is a 6SL7 -- I tried subbing with a 6SN7 but liked the SL better. The second tube is as stamped (7F7); I subbed a 7N7 but again liked the 7F7 better.
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Barley Nectar
655 posts
Feb 16, 2015
8:55 AM
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A lot to think about here. I feel that 6SJ7, 6SL7 PI setup is the way to go due to the 6.3V filaments in these tubes. Plus the gain flexibility that the SL/SN swaps provide, as Jim states, is a plus. Standard modern transformers provide 6.3V filament windings. The "7" tubes want to see 7 V for the heaters although 6.3V would probably work.
In comparing the MA-17 and the ME-18 schematics, the two amps are nearly identical with slight variations in component values. The 17 uses a choke in the PS which is oldschool. The ME-18 reflects the use of the more modern tubes of it's era.
I found this site late last night and am in the process of downloading the proper Photofact sheets for these amps. Excellent resource.
http://www.theschematicman.com/index.html
Last Edited by Barley Nectar on Feb 16, 2015 8:57 AM
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Harpaholic
630 posts
Feb 16, 2015
11:00 AM
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For anyone that's interested, my amp tech examined the
Basic difference's between an Audiosphere A-36 and an ME-18.
The A-36 has
Stock tube layout 2-6L6, 5V4, AX, AU, AT
grid leak bias on the mic preamps - fine
cathode bias on the phono input - fine
very low voltage on the preamps except for high on PI - that’ll be ok
medium volts on the power tubes- see note below
paraphase inverter - desired
cathode biased power tubes - fine
no choke - fine the only thing a choke does (instead of a resistor) is allow a little higher voltage through (after the power tubes) to the preamp tubes. More voltage, more headroom, but barely discernable to the ear when I’ve A/Bed the change.
the treble control and bass control won’t really affect the circuit, just allows more or less treble or bass to get through. Treble is same circuit as on the ME18’s “Tone"
too many gain stages - I by-passed one complete stage for Charlie.
On yours, I’m making the Phono input into a mic input, and that will by-pass a stage, that way, it will still have enough for guitar.
Last Edited by Harpaholic on Feb 16, 2015 2:04 PM
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bloozefish
179 posts
Feb 16, 2015
11:19 AM
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A bit OT, but I have a Masco Audiosphere 8 with a single 6L6...it's a little screamer.
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blueswannabe
546 posts
Feb 16, 2015
7:22 PM
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@barley, that's a graet website and resource. I have purchased from there before. You'll get all teh component lists which is very helpful.
Keep us posted on your build.
6sJ7 gives you more options...i would go with that as your pre-amp.
Last Edited by blueswannabe on Feb 16, 2015 7:28 PM
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Barley Nectar
657 posts
Feb 16, 2015
10:01 PM
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Just ordered G10/FR4 Garolyte board from McMaster-Carr. Also picked up a lb. of 60/40 rosin core. Allied Electronics has the eyelets, caps, R's. I need to look at bench stock before I order components. I have iron, sockets, pots, signal caps, etc.. Also have steel for a chassis. I normally beef up the power supply caps on my amps but I may not on this one??
I'm getting cyced...BN
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Mojokane
781 posts
Feb 17, 2015
8:06 PM
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Greetings!
I recently acquired a fairly nice condition Fanon Masco PA Amplifier 3311.
(1)6L6 (1)12AX7 and (1)6CA4.
Can anyone tell me what it would be best suited for...a guitar player friend was unloading his closet, and I happen to be there at the right time.
I am always interested in anything Masco. But never heard of the Fanon Masco. Or the (1) 6L6 amp.
Will I be pleasantly surprised? I have all sorts of speaker cabs to experiment with. Which would be ideal?
..save me a little time. I'm taking it out for a spin tomorrow night. I already changed the power cord. It doesn't seem to need anything else. It is quiet and has big balls! Thanks in advance.
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Why is it that we all just can't get along?<
Last Edited by Mojokane on Feb 17, 2015 8:08 PM
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6SN7
510 posts
Feb 18, 2015
5:03 AM
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@Mojokane. If that was the lunchbox amp on eBay on the other day, you have a excellent amp for harp or guitar. From the description/picture on eBay, it looked like the amp was untouched (unmodded) and very clean. As such, it went for a lot of money ($385 I believe) and additional $ will have to be spend to ready it for the music world.
I have been looking for something like that for an amp project and there appear to be lots of them available on eBay but you have to pick and discern the junk from the jewels. I ended up picking up a Knight 93SZ690 with a cool little speaker cabinet for similar money. Regrettably, it won't be much of a project because it is already working, but it is adorable and a nice low watt studio/practice amp.
Good luck with your purchase, I think you got a nice amp.
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Mojokane
783 posts
Feb 18, 2015
9:27 AM
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6SN7, yeah I saw that one. looked minty. About a week ago or something like that..mine is the same model..pretty sure. but I put a 3 prong and left it at that for now. Now begins the journey of finding the right speaker for it. Thanks for your feedback.
Glad to hear it is something good for harp. My guitar friend mentioned it was pretty loud. He played at a medium size bar in Waikiki and didn't need to mic it...that's LOUD..(6L6)...COOOOOOOL..
Well, we'll have a go round tonight. I have not decided which cabto take. My preference would be, after finding out which combo works best install the head inside a cab. Much easier to tote to the gig.
Looks like a "lunch box" for sure.----------
Why is it that we all just can't get along?<
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HawkeyeKane
2710 posts
Feb 18, 2015
9:49 AM
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technobird had a Fanon-Masco combo a while back that sounds similar to what you fellas are describing. Not on his site anymore though so he must've sold it....
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Hawkeye Kane - Hipbone Sam
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Barley Nectar
666 posts
Feb 18, 2015
10:37 AM
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Well, I posted three times last night on the Fanon-Masco. All three posts are missing. They were there then gone??? I always review my posts after posting.
Anyhow, you can google the amp and find the completed Ebay auction. Scroll to the last pic and you have the owners manual for that amp. Mouse over to read the manual.
For speaker, I would try a vintage Jensen P or C12R or Q, ribbed cone. That amp is about 12W so either of these speakers will handle it. Some other speaker with a similar light weight cone and smaller voice coil,
1 1/4" may work also. Very subjective but that's my choice to start...BN
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6SN7
511 posts
Feb 18, 2015
10:51 AM
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@Mojokane. No dude, don't hide it, there is some serious mojo with the cool looking amp, don't hide it away in some dull cabinet because it is easier to tote!
I read on Dave Barrett site someone had used one of these amps and was happy with it.
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Barley Nectar
670 posts
Feb 18, 2015
3:22 PM
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Ha Ha, just got the Garolyte board from McMasters-Carr. Man that is quick!
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Mojokane
784 posts
Feb 18, 2015
7:27 PM
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Had enough snow yet, peeps?
Bring your honey, a little money, and don't forget your mics and harps. Harps for sure...you can use my rig.
Barely- Nectar. thanks for the info.
6SN7- I will consider your advice, too. I can dig it.
The thing is so small anyway. I put on over sized rubber glides so it can sit on top of anything...
woo hooo! here's goes. My sista is sittin in tonight, too. Should be a barn burner!
TONE TONE TONE
To the bone bone bone!
I was super lucky to have Phoenix native, Mark Spoerner, in the audience last week. He managed to capture the vibe of the place. Some good shots. Head over to Blues In Hawaii Facebook....check out the album he took. Whatta guy!
Mojo Lens Photography...can't beat it. Super cool guy, too.
Keep up the blues chops! Soooo blessed to have such dedicated players along for the ride...and a bunch of swing dancers have taken a liking to us, too. They eat and drink, too! how's THAT?
Pretty sleepy local watering hole. Our one night out a week. Not easy, though, super fun when you feel your work has paid off. And the satisfaction from seeing people dance...good forum...thanks again!
Can't wait to hear the FANON MASCO!
And good luck with your project! BN!
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Why is it that we all just can't get along?<
Last Edited by Mojokane on Feb 18, 2015 7:36 PM
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Barley Nectar
671 posts
Feb 18, 2015
8:50 PM
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Cool Pic, B & W. Which one is you? Thanks...BN
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HawkeyeKane
2711 posts
Feb 19, 2015
6:44 AM
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Audiosphere 27 on ebay right now...
http://m.ebay.com/itm/131433323412?_mwBanner=1
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Hawkeye Kane - Hipbone Sam
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Barley Nectar
672 posts
Feb 19, 2015
7:44 AM
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That old amp earned it's keep! Still passing signal which means it is worth rebuilding. That needs a total overhaul but probably sounds good when complete...BN
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Mojokane
785 posts
Feb 19, 2015
8:49 PM
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yeah, what a beast!
BN- I'm in the middle raising my hand in praise!
(we must have been doing a gospel blues number.)
btw
The F/M was a hit. I used a pair of alnico Rola 12's.
I see what the fuss is all about.
Though, the gearhead "never totally satisfied until I try out every combination available in my arsenal" syndrome, has once again set in .
Just when I was almost ready to take the plunge for a new amp,a friend drops a Fanon Masco in my lap.
coool! I can't really see myself buying a new one....yet.
6SN7- It does look very cool...and the sound, wow! instant approval from band mates.
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Why is it that we all just can't get along?<
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Barley Nectar
673 posts
Feb 20, 2015
9:23 AM
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Those old PA amps were voiced for the human voice, not guitar. This is what makes many of them good for harmonica. Lower gain, full mids, sweet. I have several here in variouse states of operation. Only one is gig ready presently. It is a 35 W Knight which had a phonograph on top at one time. I also have the GE 12's in the original burgundy clam shell cabs. Head goes inside. It was very close to the Fender 5C5 Pro circuit as stock so I modded to that circuit.
The big thing with these old amps is the electrolytic caps are shot and must be replaced if you expect to play them. Most of them need just about everything replaced due to component drift and age. Paper and wax signal caps are always leaky. The old R's drift way out. Tech costs will add up to more then the amp is worth. Cool projects for DIY guys though. This is one reason why I am building the Masco from scratch, also I can make it fit in my cab. Great thing to do when it is below 0 outside...BN
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Mojokane
786 posts
Feb 21, 2015
6:40 PM
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...BN
good reason to buy new, only when there is a deal to be had...for sure.
Compliments on the project you are undertaking.
Hope to see and hear it someday soon.
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Why is it that we all just can't get along?<
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Barley Nectar
675 posts
Feb 21, 2015
8:30 PM
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Finished up the circuit board layout yesterday.
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Barley Nectar
683 posts
Feb 27, 2015
10:28 AM
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Got the chassis physical layout done. I am using a heavy duty steel structural drywall stud for the chassis. Chassis will measure 15 1/2" x 6" x 1 1/2". Found near everything I need for this in my bench stock. Using vintage Bogen PT/OT from old 6L6 PP PA amp. Fitting iron for this project! I will fab chassis and circuit board today. will load chassis tonight. Stay tuned for pics!...BN
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Barley Nectar
685 posts
Feb 28, 2015
9:01 AM
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jimr
79 posts
Feb 28, 2015
2:08 PM
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How does the metal speaker cab sound?
Jim
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Barley Nectar
686 posts
Feb 28, 2015
5:49 PM
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I tested it with a 17W Bogen VP-17x, it sounded fine but I didn't have it cranked. I'm going to put it together and see how it acts. This cab looks so cool, I'll figure out a way to calm it down if it buzzes??
Just got the chassis compleately drilled and worked on the eyelet board. Ran out of .156 eyelets, crap! I'm sittin in on an acoustic gig tonight. I'll do more tomorrow...BN
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Mojokane
788 posts
Feb 28, 2015
11:25 PM
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very cool photo's!
keep em comin!
Makes me want to tackle something like this!
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Why is it that we all just can't get along?<
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blueswannabe
551 posts
Mar 02, 2015
4:01 AM
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It's looking pretty good. Can't wait to see and hear finished product.
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blueswannabe
552 posts
Mar 02, 2015
4:03 AM
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A masco 17 just sold for $740 on eBay!!
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