The Amp Garage

Replaced 40uf caps with JJ 32s and it motorboats and cuts in and out. More to diagnose

pompeiisneaks wrote: ↑Thu Feb 01, 2018 11:57 pm I get :

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The requested URL /bricolages/renoamp.htm was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

~Phil

Hi guys. Refurbing this amp. Does this look close to a Princeton? Any recommended circuit changes?


http://www.jcayer.com/bricolages/renoamp.htm

The high cut would better with .0047uf or .0022uf instead of a 500pf as noted on schematic, more bass response. The 100pf caps on the volume controls would be better to be on switch or remove. Thanks for the help. Removed the 100pf on the volume pot and the clean channel became absolutely wonderful...

M Fowler wrote: ↑Tue Jan 02, 2018 5:13 am No I don't know what Ken F. discussed with Kendrick regarding this at all.new_joyzee_schematic_153.pdf

Ping Mark. Any idea how I could thicken the clean channel? It’s a little bright even tube swapping and I’m assuming inherent to the circuit. The high notes are a little thin imho

No I don't know what Ken F. discussed with Kendrick regarding this at all.new_joyzee_schematic_153.pdf Hey thanks. I will compare the two. I think my Amp is modified with fixed bias and a London power scale? May want to resurrect back to original specs and upgrade a few components based on a rebuil...

Hi I know this isn’t a Ken Fischer TW amp and has only elements of his amplifier design. Nonetheless I have a couple questions as I can purchase one locally for a very reasonable price and am curious about; the circuit design and the improvements Ken suggested via letter to first wave of purchasers....

Ragged in a bad way? May be unrealistic expectations here. I drop post master to next to mother omg and pre Pi master is good up till 4 ish then gets hollow sounding if I bring in postbox master it becomes more defined and of course louder :) I’m assuming the two masters have a relationship with ho...

For the plexi sound you need to dime that pre pi master. Have you definitely used log taper pots? You should notice the plexi channel being a bit thin at lower gain levels and getting fatter as you crank it. Also if you leave the JCM800 channel connected it might take some of the high end off. Try ...

It does beg the question though; could you not have both? ; type 2 and type 4 as they both do different things. Interesting , I just may try something like this one day. With some control over different areas there may be some possibilities there. Absolutely you can have both. And I really like hav...

I have rolled a variety of tubes into amplifiers and may get flamed for saying this...but I have discovered that a variety of tubes can sound good or horrible in a circuit despite the brand or label. It seems that the relationship between the gain stage tubes is as important as the actual tube used....

I dont see how that layout could be a plexi? It looks more like a mid 70s 2204 with a single input and switched channels http://schems.com/schematicheaven.net/manu/marshall/jmp_mastervol_50w_2204u.pdf A schematic would save a lot of effort in trying to work out exactly what you've got there. Gain, ...

On a Marshall 50 watt Plexi build I noticed the bright/normal gain seems to max out at about 10:00 on the pot from there on no more gain just a little compression. Is this typical of a 50 watt circuit?

Go through the entire tonestack to ensure it's wired up correctly. Check connections with an Ohmmeter. Put a meter on that pot (wiper and one of the sides), turn it and see if the resistance changes. From memory you won't see the full 1M but you should see a couple of hundred k. If the resistance d...

Go through the entire tonestack to ensure it's wired up correctly. Check connections with an Ohmmeter. Put a meter on that pot (wiper and one of the sides), turn it and see if the resistance changes. From memory you won't see the full 1M but you should see a couple of hundred k. If the resistance d...