M102 Arrived Today! Pics and condition questions

[StevenW]

your not going to get break up with those 6v6's in the AO-29,quite honestly it does not matter what brand or if there matched or not(as long as there not chinese),if you want to get some breakup/overdrive use effect pedals in place of the reverb tank this way you can switch the sound in and out with the reverb I-II tabs,those little AO-44 reverb amps are great and are voiced for the organ unlike a guitar amp,just get two rca to 1/4" adapters

I'm using Chinese Groove Tube 6V6's in my Fender Deluxe Reverb (reissue) and they sound killer. It came stock with Groove Tubes GT6V6-S (for "Slovakian"). They are good too, but I bought the Groove tubes GT6V6-C (Chinese) for backup, stuck them in the amp to try 'em and they sound great so I left them in. Now the Slovakian tubes are backup. The Chinese 6V6 seem to be knockoffs of the old Tung-Sol 6V6GT (black, smoked glass). Point is, they seem to be decent tubes nowadays. Like just about everything else musical produced in China (guitars, trumpets, whatever), the quality comes up after they get better at making the item. The beauty of the Chinese (and Russian and Slovakian) is they are readily available and affordable. A pair might last for years in a Hammond organ, no?



By the way, I have lots of old pairs of 6V6GT and GTA, some NOS, some used. I'm set for 6V6. The reason I'm staying with the Groove Tubes in the Deluxe Reverb for now is that they claim the amp is biased for these tubes (mine uses the "medium" 4-7 range 6V6).

[Jim Dep]

I almost went locally with a pair of Russian Groove Tube 6v6gt's for my M102. Guitar Center wanted $55 for the set though. The Chinese Groove Tubes were the cheapest, I think he said 38.00 for the pair. I've liked Groove Tubes in guitar amps too. I replaced a stock Marshall pre amp tube with a GT 12AX7 and it made a big difference. I got a brighter tone, more clean headroom and more gain. It gave me nice sparkly highs that I really like, especially on my Marshall. I decided to go with the Tonewheel General Hospital and get their Electro Harmonix 6v6gt's for 35.00 for the pair, and also put in the order for the tonewheel generator oil (vintage era). This way I can establish an account with them. I don't know how the EH's compare with the other brands, but if that's what they recommend, I'll sure they'll be fine. GC told me too that once I put in a new tube, if it's a bad tube they won't replace it. The surprised me. Every one in a while, a bad tube gets sold, and seems to be a growing problem from what I here. JJ tubes, which are normally very good tubes had a bad batch go out and quite a few guitar players were complaining that they weren't lasting long at all, and some blew right away. I think Tonewheel General Hospital will be more forgiving, I could be wrong. Hopefully I'll get the order in by the weekend so I can see how this M102 is going to do. I haven't even checked the tone wheels yet, I thought it'd be better until I have the oil ready to go.

[Tubejack]

Congratulations, that's a beautiful example of this model! I'd give anything if my M-103 had the Leslie hookup and switches. Being as you need a good pair of 6V6s, here's a link to one of the most reliable suppliers of tubes for musical instrument use:

http://www.mcshanedesign.net/tubes.htm

Have fun!

Jack

EDIT: Just want to mention that there's an alternative to the 6V6 for someone who doesn't mind modifying the amplifier a little. Numerous eBay sellers list small, 12V switching power supplies easily capable of powering a pair of 12V6s. The 12V6 is identical to the 6V6 except for filament voltage. NOS US varieties are readily available at very reasonable prices, and I've personally purchased dozens of them over the last few years. Many of those were sold as matched sets of five or ten for less than $5 per tube. Spending $6 for a 12V supply and attaching it inside the amp with a zip-tie can provide an inexpensive solution that will give you the longevity and tone of genuine '60s tubes.

[gtc]

Just want to mention that there's an alternative to the 6V6 for someone who doesn't mind modifying the amplifier a little. Numerous eBay sellers list small, 12V switching power supplies easily capable of powering a pair of 12V6s. The 12V6 is identical to the 6V6 except for filament voltage. NOS US varieties are readily available at very reasonable prices, and I've personally purchased dozens of them over the last few years. Many of those were sold as matched sets of five or ten for less than $5 per tube. Spending $6 for a 12V supply and attaching it inside the amp with a zip-tie can provide an inexpensive solution that will give you the longevity and tone of genuine '60s tubes.

Not a bad idea, as long as the el cheapo switch-mode supply doesn't inject nasty RFI into the amp.

[Sweet Pete]

That's a nice looking spinet you have there,looks like a 26-1 connector kit as well,great deal for $20.You'll find 6V6 tubes at a Guitar Centre or music store......Fender Blues Jr. uses 6V6's IIRC......a common small amp tube.The reverb amp tubes on your model are rare,6GW8.I hope your's work fine.Your M102 still has the blank RCA jack on the expression pedal doghouse,cool.Celeste vibrato totally rocks!

[Tubejack]

Not a bad idea, as long as the el cheapo switch-mode supply doesn't inject nasty RFI into the amp.

I've only tested a few of these supplies, but they were more than clean enough for use as an output stage filament supply in an organ. I've tried them in guitar amps and audiophile gear, and the results were very good. The output might need to be cleaned up with a simple filter for use in low-level stages, but I haven't used them in that application yet. Anyway, it's just something to consider as the prices of NOS continue to go up.

[Wes]

The organ already has 12AU7 and/or 12AX7 tubes, doesn't it? This means that it already has a 12V filament supply. The million dollar question, of course, is "is beefy enough to handle two more tubes".

Good hint, Tubejack.

[Hammond101]

"Fender Blues Jr. uses 6V6's IIRC"

Nope, the BJr uses EL84s. the Princeton and Deluxe Reverb models use the 6V6s.

To the above post, I believe the filiment voltage in a Hammond amp is 6.3 volts which is what a 12A?7 want's to see. At the rate a Hammond power section uses up a set of power tubes, not very often, this is a mod I would not make unless I just wanted to tinker. The reason for the Filament supply is to provide the 12v to the tubes that the amp, at about 6v, doesn't have.

[Tubejack]

The miniature 12A** tubes have center-tapped filaments, and unfortunately, they are nearly always wired in parallel for use with a 6.3V transformer winding. I haven't checked the schematic, but it's very unlikely that the Hammond amp has a 12V transformer winding. It's even more unlikely (as you pointed out) that it could handle the extra current draw from a pair of 12V6s. The upside to this is that the 1A, 12V switching supplies on eBay are really small and easy to work with. You could probably even stick one on the inside of the amp with double-sided tape or Velcro. Lately, I've been thinking about adding a switch in amps I build that will allow using either 12V or 6V tubes. I almost never build with miniature tubes, so even my low-level stages are voltage specific (6SN7/12SN7, 6SL7/12SL7, etc.). I have dozens of NOS 12V octals going back to the '50s, and I much prefer their sound to that of modern 6V tubes. Audiophile quality is much less important in an organ, of course, but there's still something to be said for the ruggedness and longevity of original 6V6/12V6 output tubes made in USA.

[Jim Dep]

Not a bad idea, as long as the el cheapo switch-mode supply doesn't inject nasty RFI into the amp.

That's a legitimate concern. I wouldn't want Radio France International spiking my speakers either.

- - - Updated - - -

I almost never build with miniature tubes, so even my low-level stages are voltage specific (6SN7/12SN7, 6SL7/12SL7, etc.). I have dozens of NOS 12V octals going back to the '50s, and I much prefer their sound to that of modern 6V tubes. Audiophile quality is much less important in an organ, of course, but there's still something to be said for the ruggedness and longevity of original 6V6/12V6 output tubes made in USA.

What about those miniture tubes with the military specs like Seymour Duncan uses in their Twin Tube Classic overdrive guitar pedal. How would those do for organ pre amps?


This is SD's desription:

The SFX-03 is a two-channel guitar preamp employing premium
subminiature type 6021 vacuum tubes. The 6021 is manufactured to meet the
stringent MIL-E-1 specification for reliability and is optimized to provide long
service life under conditions of severe shock, vibration, high temperature, and high
altitude. The tubes are configured with a high-voltage power supply for maximum
dynamic range. True-bypass capabilities are provided to allow uncolored feedthrough



But being the organ is low fidelity, you wouldn't need to run these tubes at high voltage because you don't need a "maximum dynamic range". I don't know much at all about electronics, but I'm just wondering how/ why this would or wouldn't work. Advantage might be tube longevity, but is this even a concern?

Thanks for you comment about my M102. Since I've put those pics up, I've given it a good cleaning a polishing on the cabinet. The speaker cloth really brightened up to, with a slight usage of upholstery cleaner and a good vacuuming. What I thought might be a permanent blemish came out clean! I really excited about getting this up and running!