Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

His guitar slung across his back, his dusty boots is his cadillac.

Moderators: VelvetGeorge, BUG

daveweyer
Senior Member
Posts: 681
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by daveweyer » Mon Jun 07, 2021 9:38 pm

Franco,
I hope you mean total idle current and not 65 ma per tube! If the latter, each tube is dissipating 32 watts at idle, leaving nothing left for high output, otherwise operating pure class A with a maximum power output of 30 watts per output tube pair.

Just sayin.......

daveweyer
Senior Member
Posts: 681
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by daveweyer » Mon Jun 07, 2021 9:41 pm

Flo,
They will probably work okay. Not enough beta for the West Coast Fuzz, but some fuzzes.

FloPoeKo
New Member
Posts: 15
Joined: Thu Jul 20, 2017 3:04 am
Just the numbers in order: 13492

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by FloPoeKo » Tue Jun 08, 2021 4:09 am

daveweyer wrote:
Mon Jun 07, 2021 9:41 pm
Flo,
They will probably work okay. Not enough beta for the West Coast Fuzz, but some fuzzes.
Hi Dave, thanks for taking the time to write. Maybe you have some more information from experience. What bugged me recently:
A) It seems the NKT275 were the standard transistor in the Dallas Arbiter Fuzz Faces, whereas the AC128 seems to be the one first appearing in the 90´s reissues.
Now, the NKT275 is supposed to be in the 30-90 Range for beta, the AC128 from experience more in the 80-150 Range. I tested a fuzz-face with 80 (Q1, trimmed to 0.54-0.60V) and 90 (Q2 trimmed to 4,5 - 5V ), and it sounded quite right.
Any thoughts on how to do this better?

B) Also: How were the NKT275 or whatever stock transistors they used back then in terms of leakeage? I have an assortment of pulled Mullard OCxx and they´re really quite low (around 90µA). So I became a bit suspicious of my TFK´s with 200µA...

daveweyer
Senior Member
Posts: 681
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by daveweyer » Tue Jun 08, 2021 1:50 pm

It seemed that whenever we replaced the transistors in the original Arbiter units, everything improved, leading me to suspect that they were really the cheapest "bottom of the barrel" transistors Arbiter could find on the market at the time.

My solution for finding good PNP low power signal transistors came from Allen Organ Company. Since it was typical to find over a thousand of those PNP transistors in one of their organs, I knew they had done their homework on getting solid and repeatable results from their transistor suppliers. Allen was probably the biggest single user of those devices, having purchased millions of them for their products. In the early days it was the 2N591, but that later changed to the OC series and included the Matushita product offering of the same type as well.

The OC models ran generally lower in current gain but with good leakage characteristics, and they are a lot easier to find than the 2N591. I have seen "white dot" 2N591 transistors with gains of 180 and very low leakage, Allen used them for low level preamp stages in their solid state amplifiers where low noise was critical.

Opinions vary, but let's say there is a loose agreement that in a fuzz unit Q2 is best at over 100hfe (120-150) and that Q1 should be at least 90 (possibly better at 100 -110 or thereabouts).

Low leakage is a plus in either situation. So it looks like you are on the right track.

User avatar
Xplorer
Senior Member
Posts: 2469
Joined: Sun Apr 19, 2009 5:27 pm
Just the numbers in order: 7

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by Xplorer » Thu Jun 10, 2021 12:21 pm

Hello everyone ! :)

Here's my version of the west coast fuzz, thanks a ton to Dave for his help, this fantastic fuzz design, everything ... !!!!
MERCI !!!!

It's the best fuzz i ever had, and it's almost not even a fuzz, rather a magnificent boost. Glassy and organic at the same time, it's truely made for the west coast amp. Here i use mainly ( or only ? i don't remember ) the normal stage of the fuzz. For the wild stage, i'll present some other clips later, but i'm running out of time, i could re do burning desire because this one is a pity.

This fuzz has so much power that even with the vol at 1 on the amp, it almost killed my SPL Transducer made for 100 watts only , it got sooo hot, and the resistors were making crack noises.

Thanksfully Bill helped me figuring out some impedance solutions to divide the power : two outputs into two attenuator ( spl + homemade, both in 8 ohmand the amp in 4 ohms when for years i had the amp set to 8 ! ) .

Clips, who knows and burning desire. i'll delete this folder later :

https://drive.google.com/drive/folders/ ... sp=sharing

pictures and a new layout i designed as i sadly broke tek's board, so i re did it the old school way :

https://imgur.com/a/V4fDSoK
Last edited by Xplorer on Thu Jun 10, 2021 6:40 pm, edited 1 time in total.

User avatar
bill bokey
Senior Member
Posts: 485
Joined: Sun Jan 02, 2011 2:54 pm
Just the numbers in order: 13492
Location: France
Contact:

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by bill bokey » Thu Jun 10, 2021 12:57 pm

I have not yet found the time to build a 3 transistor fuzz but I am currently working on a West Coast Replica

Here are some photos :
https://www.facebook.com/media/set/?van ... 4893796034

It's changed a bit since I took these photos. The power supply is now 600V on the plates and 300V on the screens, through the choke.


And here's how it sounds with a West Coast modded Fuzz Face and a vintage wah :


daveweyer
Senior Member
Posts: 681
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by daveweyer » Sat Jun 12, 2021 7:22 pm

Wow!!
The forum comes alive again, and it's wonderful! Bill even figures out a way to post an embedded video!

This is just great. I encourage anyone and everyone to chime in on these incredible projects. As for me, I'm lovin it!

Thanks so much guys, for sharing these labors of love. I'm listening again and again, hoping to offer some choice comments.

FloPoeKo
New Member
Posts: 15
Joined: Thu Jul 20, 2017 3:04 am
Just the numbers in order: 13492

Re: Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

Post by FloPoeKo » Tue Jun 15, 2021 9:20 am

Guys, could this be real or is this offering a fake?

https://www.ebay.com/itm/265143925091?h ... UK7KZ2pSUY

Post Reply