Spud: what, again!?!

[MellowTone]

Originally Posted by tubelab.com

It looks like some version of this board will happen. When, is a hard question to answer. I have a full time engineering job that consumes most of my time. Tubelab is a part time venture that barely covers its expenses. To fix this, I have decided to eliminate the warehouse rent by closing out the warehouse. I have already informed the landlord that June is my last month. This gives me 25 more days to remove all my stuff. I will be very busy moving stuff until July.

After that I need to fix by messed up website, re-do some of the instructions for the SSE to match the new board revision that is coming.

I still need to finish the design work and testing on the Spud SE board, re-do the layout, get some boards made, build, test and document them, and create a set of build instructions.

The reality of all of this work says that a fully finsihed board with a parts kit and a proper set of instructions is still several months away if no major interruptions come my way. A few boards may be available to early adopters sooner. These are for the porpose of finding potential problems, and verifying the instructions and parts kits.

Sounds excellent. As I said before, I'd be down for 4 boards if the option for PP is available (probably 2 if not) I'd be more than happy to be one of those early adopters you speak of...

A new SSE board revision? Are there any major changes planned, or just more of a housekeeping thing?

[tubelab.com]

A new SSE board revision? Are there any major changes planned, or just more of a housekeeping thing?

It started out to be a legal thing. Last year it was determined that I had to change the name. The trademark owner of a similar name agreed that I could continue to sell my existing stock of PC boards until it was depleted. New stock couldn't display the old name. Last year I did a new layout with only the name change, however the PC board vendor screwed up and used the old artwork. There are a few of those boards left, and new ones in house.

This year I submitted a new layout with the name change and two additions. A pair of small silicon diodes has been added in series with the 5AR4 plates, and a CL140 inrush current limiter has been added in series with the HV CT on the power transformer. Both additions are intended to improve rectifier tube reliability. Both can be jumpered out if desired to make the board exactly the same as the old one. Some users don't want silicon or other nonlinear devices (the CL140) in their amp. Yes, you can build it without the 10M45 too.

The rectifier tube in the SSE can operate at the edge of peak current spec with a Hammond power transformer and some of the current production tubes blow up.

These changes can be added to an existing SSE, but if someone has a good working amp, don't mess with it. There was a rash of bad 5AR4 batches about 2 years ago and it wasn't uncommon for a builder to try 1 or 2 tubes and watch them spark out on power up before finding a good one. It seemed that JJ and Shuguang were having problems at about the same time. Todays tubes seem OK, but it could happen again.

[pso]

The spud board also includes the CL140?

[tubelab.com]

The spud board also includes the CL140?

It is not on the current proto board. The Spud SE uses solid state rectification so it is not really needed, but I can add it if it is wanted.

[pso]

I have plan to use tube rectifier, would be nice to protect the tubes though the 6LR8 is inexpensive but hard to find in Europe, and offer on Ebay is not very wide.

[pso]

I will use a power transformer 320-0-320 and the B+ would be too high with the diodes, also a 5AR4 looks a lot more.

[squiffiness]

Originally Posted by tubelab.com

It looks like some version of this board will happen. When, is a hard question to answer. ..A few boards may be available to early adopters sooner. These are for the porpose of finding potential problems, and verifying the instructions and parts kits.

I wish I could commit to being an early adopter, being keen to have a Tubelab Spud. Until I square away my employment situation and get back on someone's payroll, I can't.

If that changes, I would dearly love to be an early adopter. I do agree with 'pso' from the earlier thread about the tube rectifier, it does look rather nice in a spud, even though it would then be a 'one and a shared' tuber. Someone's gonna hafta come up with a name for that...I'd rather have the board.

BTW: the potential to convert one of these into a guitar amp has dramatically increased the WAF (i.e. wife acceptance factor) when I do finally have the funds to play with my hobbies again...she plays a Jackson rather loud on a sand-based Peavey currently. A push-pull unit based on 6LR8's would be a conversation piece for her gigs.

Glad the Tubelab collective has responded to this thread positively. Keep it up.

[tubelab.com]

the potential to convert one of these into a guitar amp has dramatically increased the WAF

It works the other way here. The louder ANYTHING is the less the WAF. I can't play the guitar at all when she is home unless I am in the other end of the house without an amp. As we plan out our retirement house it will have a "music room" as far as possible from the living quarters with as much soundproofing as possible. I have my daughters old drum set stashed under the staircase in the house in West Virginia. She hasn't found it yet. Kinda hard to turn down the drums.

I have plan to use tube rectifier

The Spud SE as it exists now uses a silicon rectifier in bridge configuration without using the transformer CT. This allows operation from cheap Antek toroids. It can be wired for a power transfoirmer with a CT also. I am not planning to put a rectifier tube on board since that will increase the board size and drive up the cost. I believe it is possible to wire an off board socket for a 5AR4 without any additional components using the on board filter caps. I will have to investigate this since I will need a negative voltage for the CCS....if I even use one. I am experimenting with just a big resistor and a fairly large negative voltage. Tube rectifiers are almost mandantory for guitar amps, so I'll look into it.

[squiffiness]

Originally Posted by tubelab.com

It works the other way here. The louder ANYTHING is the less the WAF. I can't play the guitar at all when she is home unless I am in the other end of the house without an amp. As we plan out our retirement house it will have a "music room" as far as possible from the living quarters with as much soundproofing as possible. I have my daughters old drum set stashed under the staircase in the house in West Virginia. She hasn't found it yet. Kinda hard to turn down the drums.

Just take a small, portable generator into the hills and scare the local fauna with some power chords. You might even make the news and get some free publicity.

My buddy in Kingston plays the drums (among other things) and uses practice to drive away the demons of a day at work writing software for a life insurance company.

The Spud SE as it exists now uses a silicon rectifier in bridge configuration without using the transformer CT. This allows operation from cheap Antek toroids. It can be wired for a power transfoirmer with a CT also. I am not planning to put a rectifier tube on board since that will increase the board size and drive up the cost. I believe it is possible to wire an off board socket for a 5AR4 without any additional components using the on board filter caps. I will have to investigate this since I will need a negative voltage for the CCS....if I even use one. I am experimenting with just a big resistor and a fairly large negative voltage. Tube rectifiers are almost mandantory for guitar amps, so I'll look into it.

With the inexpensive board services out there, perhaps a peripheral board would be easiest to maintain cost and size control, while giving some flexibility to the overall design, even swapping rectifier tubes for the more advernturous. That way, you could keep the Pi filter in place after the current bridge rectifier design, pop in some jumpers and add the extra stuff like the CL140 and the bypass diodes to a small (say 5mm by 5mm) rectifier board. Just a thought.

[squiffiness]

Originally Posted by tubelab.com

It works the other way here. The louder ANYTHING is the less the WAF. I can't play the guitar at all when she is home unless I am in the other end of the house without an amp. As we plan out our retirement house it will have a "music room" as far as possible from the living quarters with as much soundproofing as possible. I have my daughters old drum set stashed under the staircase in the house in West Virginia. She hasn't found it yet. Kinda hard to turn down the drums.

So is your next project vacuum tube based noise cancelling headphones? Maybe THAT is the use for those pencil sized hearing aid tubes mentioned earlier in this thread...an UNhearing aid. Hmm...