The Last Bass Outpost

Yep. There are FZ-1 clones out there too but some of them will cost you as much as a vintage FZ-1.

I built the FZ1 when restoring my EB0F. Took me some time to locate 2N270's, but I think I ended up on about $10, including spare 2N270's. Prices on 'botique' stompboxes are sick, you ask me.

I have been warned off changing my current 6CA7 based amp over to 6550 - that was my first idea (actually KT88s, which is what I asked about, but shouldn't make a difference) by my amp tech, who I've used forever and is really good; knows Canadian amps inside out.  I don't remember the details but it was something to do with voltage (don't remember even if it was plate or whatever).  Might not apply to other EL34 based amps, but I seem to recall that he said  it would, depending on what voltages they were running.  I do remember he said double check the power supply part of the schem and if the voltage is over/under X then no go, and he was right (about the voltages in there)

A 6550A can handle most situations EL34´s are in, maybe except those with 800VDC anode voltage.  The 100mA higher heater current is negligible in most cases, but you might have to alter the bias cct some. Amps that uses 6L6GC tubes on the other hand, might have a heater winding that cannot handle 6550A´s.That said, I never had a Garnet in for repair and know nothing about them, so I say trust your tech by all means!

I considered the V4.   .... but I sold off all my vintage 12DW7s I had laying about 

JJ makes decent 12DW7 tubes, you even have a choice with section is high gain! I have used them in three V4´s, seems to work fine.

Amptech is making me hesitate on the HD130 front now too (I actually have a 115RH tho - upgraded the speaker to an EV and love the damn thing).  I'll have to read that over a few times, but it sounds like it'd be easy enough to mod the reverb channel to be tonally the same as the non-reverb bass channel.  But I wonder - what is it about the preamp you don't like - I am not looking for drive, but clean headroom (let the pwr section do the work) and tight ample bass; dark is OK, as is neutral, but bright is definitely not what I am after (makes things harder considering I am looking at geetar amps for the reverb).  I do drive my current Garnet's pre a bit sometimes, but I am trying to move away from that.  These tend to be a lot cheaper on ebay; not very common around here, though I do see them periodically so I could try one, eventually. ... so how do I tell if it's tube or ss driver?  All the ones I have looked at (as far as I recall) have had a single 12A_7 in them - since the pre is ss if I see that then that's the one?

If you need a tad more headroom and have a 50W head now, the HD will do fine. When I say drive, I mean if you have a hight output instrument AND play very loud, the musicman can sound harsh, I think. It can handle most pickups, but active or high output the preamp collapses a bit. Therefore the pre-in suggestion. Example; if I play a rock gig with a mudbucker equipped bass, I bring a marshall superbass - sounds better when driven hard, in my ears. And another thing, you will not have tons of lo mid punchiness at extreme volumes - the OT is to small i guess. But good sounding, loud and clean with non aggressive instruments.

Also noticing that MM HD130s are surprisingly affordable on ebay.  There seem to be 2 versions - the standard HD130 guitar/bass version and the HD130 reverb.  From what I can tell the only differences (other than the reverb/trem) is the channel 2 bass EQ cap (and therefore the corner freq of that tone control - mid and treb tone controls look the same, as is the bass cap on Ch 1) as well as having a Deep vs Bright switch.  The rest looks pretty much the same, though some things are laid out differently.  Anybody got any opinions of how much difference this makes - that deep switch useful or just mud city (the bass cap is easy enough to change out)?  Does it do anything that can't be achieved with the EQ?  I'm cool with the ss preamp.

I´ve had a HD130 since 1993, it´s a great amp when you get to know it. I spent a few years finding speakers for it (see other threads) but eventually found a 212 and a 115 musicman cabs, the 212 i put neo´s in and the 15 i put a reconed EVM15L in. Love it.

A note on the eq, as you say the 2 channels have only cap differences, but they sound really different. The bass channel is a ´bass cut´channel, and in most cases this channel sounds best for bass guitar. I think the general eq opinion on HD130´s is to use the bass channel with the deep switch engaged. I like that best too.

The switch is as you see from the schematics just a large cap in series (between the preamp and the driver) but it really gets things deep. It does things the preamp cannot. I found it useful when experimenting with cabs too. Another thing, I put a preamp in jack on it, so if i need to have a lot of gain (don´t like the ´drive´sound on musicmans) I just use another preamp. Power enough.

Another note, I have the tube driver version. I know they changed to solid state driver for reliability reasons, but I have had quite a few musicimans on the workbench over the years (seems to be a lot of them here in Norway) and never had any tube driver related troubles. But i have repaired maybe 3 or 4 solid-state drivers. As a side note all of those had stock caps in power supply, so maybe the tube driver handles PS issues better. Quite a few with arced sockets too (high voltage here) but fresh caps and sockets and these amps are very reliable. Good sounding, with some personality.

If you want to, you could set it up with 6550 and probably have more headroom. I did think of doing that myself, but if you have a strong EL34 set it delivers nicely. You will have to use a set that actually handles 800V, though. We have 240V in the walls here; when these amps were made we had 220. These 20V turns them into monsters if you have no bucking transformer!

and maybe one for a passive diode overdrive, just for sh!ts and gigs.

If you like a little fuzz, go fuzztone:-) Gibson had some cool fuzzes mid 60's, few parts and lots of fuzz!

Isn't there some weirdness with mixing pickup impedances, whereby the lower impedance pickup will dominate the higher impedance unit?

There certainly are many factors involved when mixing pickups, but as for the stock EB-3 one cannot say that the lower impedance bridge actually dominates the higher impedance neck pickup. Obviously, the mudbucker is also magnetically stronger than the bridge PUP also.
Then you have the coil, putting the system electrically out of phase. Um.. was that 180 degrees out of phase because of the choke? don't remember. Didn't chromium or someone else here have a more scientific explanation on the setup of EB-3 pickups?

Anyway, as I have stated before (please no attacks from the stock pickup lovers here ) my personal favourite blending solution is
to wind a mini sidewinder to play in phase with the mud, toggle or blend setup, no choke. An equal impedance here will actually have the bridge pickup overpowering the mud some because it will not be as muddy. I have tried to overwind stock mini HB's, put in stronger magnets etc. but with no real luck.  I have to admit though, there is nothing wrong with enjoying the original quirks of the stock cct, the '61 to '65 EB's are a joy to play anyway.

The bridge PUP should not be noisy, but it does have a low output. If you 'even out' the balace between neck/bridge and add gain/eq on the amp, well it will have some noise. Feedback can be avoided by re-potting, but then you might just have loose components within the pickup assembly. If the coil wiggles, etc..

It's fairly easy to bypass the coil, your bass will still be stock. It should not be necessary to remove the harness, just clean it.

Personally, I like a standard toggle or blend switch (I don't care much for the choke) and again - this can be done without drilling or messing up. Or you could get a CTS push/pull volume knob, and be able to put the choke in or out of cct.

And welcome:-) lovely bass!

I used a seymor duncan stacked jazz pickup in bridge position many years ago. It was noiseless, and could produce some trebly tones but I don´t recall any clank But the log it was in was not made of maple either, so who knows...

Allan Holdsworth went from a fairly battered SG Custom in Soft Machine (as did his replacement, John Etheridge) and wound up using a Strat, modded with dual Dimarzios, with Bruford. He then went over to the tiny Carvin guitars he still uses.

Maybe those guys just broke their Gibsons? The rigors of touring, especially as a 2nd tier act, probably saw a lot of headstocks getting broken in the back of the van, etc.

Allan actually had 3 SG´s at different times, i think 2 customs and a standard. At the time he only had one at a time, he just could not afford to have a lot of guitars. I believe the strat move was due to tremolo use, he liked the sound and playability of the SG´s. But the last SG he had, he had customized with a paint job - but Tony Williams sold it when Allan was on vacation in England:-)
Personally, I think the sound he had with a custom SG plugged into a head and cab is unbeatable, though listening to him is magic even today. He confirmed the SG story last time I met him in Oslo. The white three pickup custom he used with soft machine I think still belongs to a US recording studio.