Interstate 88 Head Complete

[Ed_Chambley]

Just a front photo.  Going today to test speakers for the cab.

[tubenit]

Good job!  Looks great.

I'd love to hear a sound clip if that's possible and you have time & interest in sharing?

With respect, Tubenit

[Ed_Chambley]

Good job!  Looks great.

I'd love to hear a sound clip if that's possible and you have time & interest in sharing?

With respect, Tubenit

Plan on doing a few clips once I complete the cabinet.  The amp is so bottom strong, which is what I was going for, I need some speakers that will do it justice.  The only cab I have that will handle it is a 12 with 2 weber alnico's and they go straight into compression.  It actually sounds better with full range speakers.  It is a great very round sound that I wish to demo along with the break-up tone.  It is very versatile to be so simple.  I found the speakers and ordered them today.  Should have it all together in a couple of weeks.

Thanks for the interest.  I plan to post some better photos of everything as well.

[SILVERGUN]

Really great stuff Ed,
From the initial thread though all of your work and problem solving,,,this has been very inspirational to watch...

It's guys like you that make me want to push forward...thank you for that and thanks for sharing all of your work with us!
 

[Tone Junkie]

Looks great Ed I love the faceplate . I was watching this really hoping you would have got those KT120 tubes working but KT88 are nice I have a good matched set of those. But will still probably use KT66 if I ever get around to it .
 Its a shame  I never play anyware that I need more than a 30 watt amp anymore.
Thanks Bill

[Ritchie200]

Is that volume set on 10?   Good man!  Can't wait to here this thing.  Are you sure you don't want to put a MV on this thing?  Welcome to the 88 club!

Jim

[TIMBO]

COOOOOOOOL

[Jack1962]

Great Build  Ed , what speakers did you decide to go with?

[Ed_Chambley]

Great Build  Ed , what speakers did you decide to go with?

I checked out some Eminence Neo Magnets.  They are represented as Bass speakers, but looking at the specs and cabinet requirements they are the same as the full range Delta's.  Side by side, the only difference I can tell is a lot less weight.  I like to have bass notes hold together and really like the amp with my Altec 12's from the 80's, but the altec's are a little light in the wattage area.  These Basslite Eminence have a very similar character, but a smoother delivery.  IOW, they will not hurt you if you are facing the cab, but still have the upper mids needed for guitar.

[Ed_Chambley]

Is that volume set on 10?   Good man!  Can't wait to here this thing.  Are you sure you don't want to put a MV on this thing?  Welcome to the 88 club!

Jim

Jim, the knob controls from left to right.  Gain, Treble, Bass and Master Volume.  Sorry to disappoint, but the cabinet it is hooked to is an old fender 2 12 and the volume is nowhere near dimed.  I like the old Altecs in the cabinet, but playing a 335, they want to jump out of the cabinet.  When I tried it with an Ashdown, 4 10's that is when I knew I needed to find something similar, but better suited for guitar.

[Ed_Chambley]

Really great stuff Ed,
From the initial thread though all of your work and problem solving,,,this has been very inspirational to watch...

It's guys like you that make me want to push forward...thank you for that and thanks for sharing all of your work with us!
 

Thank you SG.  I am glad you are inspired by being hardheaded, because that is the only reason I built this amp.  I can't believe I had so many cap problems, but the high voltage is paying off nicely.

[Ed_Chambley]

Looks great Ed I love the faceplate . I was watching this really hoping you would have got those KT120 tubes working but KT88 are nice I have a good matched set of those. But will still probably use KT66 if I ever get around to it .
 Its a shame  I never play anyware that I need more than a 30 watt amp anymore.
Thanks Bill

I have a few GEC KT66 and I did run them for a short time in the amp.  They sounded great, but were easily overdriven.  The reason I plan to make a number of demo's is to show that no matter the output volume, you still have the ability to go from ultra clean to Vox chime by simply turning up the treble to full on heavy by bringing up the bass.  I have studied this circuit and compared it with others and I cannot understand it completely.  Part of it is due to low voltage EF86, but something else is going on and I really cannot get how the overdrive hides in the tonestack.

I built a similar amp but with a fender twin preamp for a friend.  We did get a good set of KT120's for his.  In his amp the difference in KT88 to KT120 is more bloom on the bottom end and it is very noticeable.  I have not given up on the 120's and have a lot of Tung-Sol USA 6550's which sound nice in it, but the KT has an advantage in that they are not as stiff.

Attached is the schematic again.  Hey Jim, it does have a master.

[Tone Junkie]

Ed you said you liked the dual PEC much better than the alpha,s . What are your thoughts there, just curious. Im all for better if I can get decent improvement .
Thanks Bill   

[Ed_Chambley]

Ed you said you liked the dual PEC much better than the alpha,s . What are your thoughts there, just curious. Im all for better if I can get decent improvement .
Thanks Bill   

PEC pots track much more consistent in a dual pot.  For instance, if you put a meter on both of a alpha 250kl you will find areas over 50k apart and since the LarMar Master replaces the 220k resistors in a LTPI and the pot feeds the screens it is just too far apart and very noticeable.  In a single pot it doesn't make any difference, but I still prefer CTS pots over alpha simply because you can disassemble them and use a pencil to get rid scratchy spots and not have to use spray.  It just works better for me.