Quote from: indianmike on February 26, 2018, 11:39:24 AM
l own a park g10r amp i came across in early 1990. most of pots were either frozen or scratchie. sprayed all inside wiper arear and also at the shaft male female seams. still scratchy but got more movement when using wd40 lithium grease spray on shaft seams. still scratchie. will change em all out for same value audio where i can slowly dial in sounds iam looking for.but will continue to upgrade the amp in which i love the clean sound i love. the reverb has been a on and off project over the years swapped out cheap belton reverb tank for a 17 1/2 hammond acoutronics sounded great but too large for cabinet in which i knew but was curious. So i spoke to a engineer @ acoutronics and gave em the belton tank numbers and told em was looking for a better sustain and more larger sound. they sent me a med decay 9 1/4 tank was better but still was set on finding real spashy wet dripping surf reverb. so i went with a modkits with a long decay 8BB3C1B and never looked back. it sounds like a fender princeton or a fender stand alone reverb unit. i know i could have bought another amp bla bla bla. but i love this amp cause of its tone and cause its portable.  now i want some input advise as how to install a effects loop and line output. please help.
what are the best chip mods i can use for the jrc4558dd 8 pin ic i have four of them would  TL02 ic be best for all of the 4558DDs to make it less hiss and quiet and bright. what about the power transistor with the heat sink. please open to suggestions thank you Indian Mike

Quote from: indianmike on March 21, 2018, 02:29:16 AM
swapped out the 4558 ics for texas instrument TL072 type very well controled far less hiss iam very please all pots were replaced with audio type just got in a 2.2k audio. I dont know if its the mod tank but reverb seems a little smaller sounding even at full up. the eq seems to be working ok. any change due from swapping from linear to audio on some of the pots. what i mean should some of them be linear than all audio maybe in the eq section. any and all suggestions considered.  On this how can i enhance the tone maybe different caps vintage type if so would bring out more hiss white noise ect. please let me know. thanks mike.

Quote from: indianmike on March 21, 2018, 02:29:16 AM
(park g10r amp)swapped out the 4558 ics for texas instrument TL072 type very well controled far less hiss iam very please all pots were replaced with audio type just got in a 2.2k audio. I dont know if its the mod tank but reverb seems a little smaller sounding even at full up. the eq seems to be working ok. any change due from swapping from linear to audio on some of the pots. what i mean should some of them be linear than all audio maybe in the eq section. any and all suggestions considered.  On this how can i enhance the tone maybe different caps vintage type if so would it bring out more hiss white noise ect. please let me know. thanks mike.

swapped out the 4558 ics for texas instrument TL072 type very well controled far less hiss iam very please all pots were replaced with audio type just got in a 2.2k audio. I dont know if its the mod tank but reverb seems a little smaller sounding even at full up. the eq seems to be working ok. any change due from swapping from linear to audio on some of the pots. what i mean should some of them be linear than all audio maybe in the eq section. any and all suggestions considered.  On this how can i enhance the tone maybe different caps vintage type if so would bring out more hiss white noise ect. please let me know. thanks mike.

Quote from: phatt on February 28, 2018, 07:07:41 AM
If you want an FX loop just break the circuit before the master volume and wire up 2 sockets in the back panel.

I doubt there would be much benifit from swapping chips.
Any hiss is likely circuit design and little to do with the chips used but try out LM833 if you want but your hiss might get worse.
It's a gamble. xP

If you want more treble then raise the value of the slope resistor in the tone stack. (I can't read the value on the schematic I found)

And/Or lower the value of C25 which is 470pF,, try 150pF ~ 220pF.
Of course more treble will mean MORE hiss.

Power chip ,,, forget that idea.  :loco
If you want more wattage then you need a bigger power transformer.
smarter to buy another amp.
Or slave a larger power amp and speaker from the FX loop which can work as line out.
If you want more detail then track down a clear schematic for folks here to help you. :tu:
Phil.

Quote from: indianmike on March 01, 2018, 01:03:03 AM

Quote from: phatt on February 28, 2018, 07:07:41 AM
If you want an FX loop just break the circuit before the master volume and wire up 2 sockets in the back panel.

I doubt there would be much benifit from swapping chips.
Any hiss is likely circuit design and little to do with the chips used but try out LM833 if you want but your hiss might get worse.
It's a gamble. xP

If you want more treble then raise the value of the slope resistor in the tone stack. (I can't read the value on the schematic I found)

And/Or lower the value of C25 which is 470pF,, try 150pF ~ 220pF.
Of course more treble will mean MORE hiss.

Power chip ,,, forget that idea.  :loco
If you want more wattage then you need a bigger power transformer.
smarter to buy another amp.
Or slave a larger power amp and speaker from the FX loop which can work as line out.
If you want more detail then track down a clear schematic for folks here to help you. :tu:
Phil.

thanks and i contacted park and they are looking into getting me the schematics for both park g10 and park g10r. try to up load them to this site for you to view. Hopefully will be able to offer advice based on what values are present. thanks for your help Phatt

swapping out all the pots all making scratchie noise. there is one that clearly says 2.2k (2 period 2k )located on mid control. i cant read the schematic is it a misprint value for this is it 22k if not what other value could i use instead.

Quote from: phatt on February 28, 2018, 07:07:41 AM
If you want an FX loop just break the circuit before the master volume and wire up 2 sockets in the back panel.

I doubt there would be much benifit from swapping chips.
Any hiss is likely circuit design and little to do with the chips used but try out LM833 if you want but your hiss might get worse.
It's a gamble. xP

If you want more treble then raise the value of the slope resistor in the tone stack. (I can't read the value on the schematic I found)

And/Or lower the value of C25 which is 470pF,, try 150pF ~ 220pF.
Of course more treble will mean MORE hiss.

Power chip ,,, forget that idea.  :loco
If you want more wattage then you need a bigger power transformer.
smarter to buy another amp.
Or slave a larger power amp and speaker from the FX loop which can work as line out.
If you want more detail then track down a clear schematic for folks here to help you. :tu:
Phil.

thanks and i contacted park and they are looking into getting me the schematics for both park g10 and park g10r. try to up load them to this site for you to view. Hopefully will be able to offer advice based on what values are present. thanks for your help Phatt

l own a park g10r amp i came across in early 1990. most of pots were either frozen or scratchie. sprayed all inside wiper arear and also at the shaft male female seams. still scratchy but got more movement when using wd40 lithium grease spray on shaft seams. still scratchie. will change em all out for same value audio where i can slowly dial in sounds iam looking for.but will continue to upgrade the amp in which i love the clean sound i love. the reverb has been a on and off project over the years swapped out cheap belton reverb tank for a 17 1/2 hammond acoutronics sounded great but too large for cabinet in which i knew but was curious. So i spoke to a engineer @ acoutronics and gave em the belton tank numbers and told em was looking for a better sustain and more larger sound. they sent me a med decay 9 1/4 tank was better but still was set on finding real spashy wet dripping surf reverb. so i went with a modkits with a long decay 8BB3C1B and never looked back. it sounds like a fender princeton or a fender stand alone reverb unit. i know i could have bought another amp bla bla bla. but i love this amp cause of its tone and cause its portable.  now i want some input advise as how to install a effects loop and line output. please help.
what are the best chip mods i can use for the jrc4558dd 8 pin ic i have four of them would  TL02 ic be best for all of the 4558DDs to make it less hiss and quiet and bright. what about the power transistor with the heat sink. please open to suggestions thank you Indian Mike