Getting ready to do wopl 400 build

[roccus]

Now that I have been running the new WOPL400 connected to the Carver C-1 for a few days I have had a chance to really put it through it's paces and mess around with the new set up. One thing I notice and not sure why yet is I have no where near the bass I had with the stock 400 connected to the Pioneer SX 939 that I was using for the preamp section. The stock 400 connected to the 939 bass was so powerful it would shake the whole shop windows rattled things falling off of shelves and my wife said she could feel the bass in the house that is about 70' away from the shop. so the stock 400 through the 939 would literally shake the ground. I have not been able to get this kind of bass out of the new set up. I know it is not the speakers as they are the same so either the new amp or preamp must be holding the bass back

 

[laatsch55]

In the WOPL configuration you are only down .(point)13 db at 10Hz. Stock configuration starts rolling off at 40Hz.....it is not the amp....

 

[roccus]

I'm going to run it through the 939 just to see what happens this will tell me for sure

In the WOPL configuration you are only down .(point)13 db at 10Hz. Stock configuration starts rolling off at 40Hz.....it is not the amp....

 

[Northwinds]

Were you using the tone controls or loudness on the 939? The bass from any of my WOPL's would crack the walls. That is with using the Perreaux SA3, The Carver C1 and the Kenwood Basic C2 as preamps. I don't use tone controls period

 

[roccus]

I only use the tone controls at low volume to give the bass a bit of a boost but when I crank it I turn the tone/loudness switches off. When I say I am lacking bass with the new set up that is even when I put the tone/loudness buttons on crank bass knobs full and boost the EQ to full bass I will pin it down just by connecting the wopl to the 939 if I get my heavy bass back then I know it's the C-1 if not then it's the amp

Were you using the tone controls or loudness on the 939? The bass from any of my WOPL's would crack the walls. That is with using the Perreaux SA3, The Carver C1 and the Kenwood Basic C2 as preamps. I don't use tone controls period

 

[roccus]

OK it's the C-1 connected the wopl400 to the 939 have tons of bass... so is it how the C-1's are or maybe if I recap it it will straiten it out?? Maybe I should move this over to the Carver forum.....

 

[laatsch55]

Most PL and Carver gear of that Era did not have exceptional low frequency response. Post the schematic. Joe has helped me improve the bass section in the 2000, 3300and 3600.

 

[OneTonScoutII]

Most PL and Carver gear of that Era did not have exceptional low frequency response. Post the schematic. Joe has helped me improve the bass section in the 2000, 3300and 3600.

is there a write up of this in a thread for the 2000?

 

[roccus]

Is there a way I can attach or upload a PDF file here?

Most PL and Carver gear of that Era did not have exceptional low frequency response. Post the schematic. Joe has helped me improve the bass section in the 2000, 3300and 3600.

 

[roccus]

C-1 service manual... can anyone open it??



Here is a doc on a Bill mod for the C-1 from the Carver site

View attachment C-1mod.txt

 

[bill7621]

C-1 service manual... can anyone open it??

View attachment 26282

It opens right up.

 

[roccus]

Great!! thanks maybe Joe can help me make a wolpolish C-1

It opens right up.

 

[Gepetto]

Great!! thanks maybe Joe can help me make a wolpolish C-1

Make sure you have all the switches in the OUT position. The Infrasonic filter will kill your bass response.

Replace IC7 with something like an OPA2134 mounted on the Brown Dog adapters and get rid of the crappy RC4136 op amps used throughout this design, especially in IC7, the only one that counts in straight through mode.

Replace C217 and C317 with at least new parts. Better to replace them with polypropylene non polar replacements of the same 22uF or higher value.

With all switches in the OUT position, there is only ONE RC4136 gain stage in the audio path.

Good luck.

 

[jbeckva]

C-1 service manual... can anyone open it??

(whacked ebil copyright issue.. jbeckva)

Here is a doc on a Bill mod for the C-1 from the Carver site

View attachment 26283

Sorry bout that Ray, but Hifi Engine might have an issue with using their work. Just keepin' the forum outta hot water..

 

[roccus]

Thanks Joe basically this sounds like the BillD mod... think I will order the parts and see if I can make this C-1 stand up and roar

Make sure you have all the switches in the OUT position. The Infrasonic filter will kill your bass response.

Replace IC7 with something like an OPA2134 mounted on the Brown Dog adapters and get rid of the crappy RC4136 op amps used throughout this design, especially in IC7, the only one that counts in straight through mode.

Replace C217 and C317 with at least new parts. Better to replace them with polypropylene non polar replacements of the same 22uF or higher value.

With all switches in the OUT position, there is only ONE RC4136 gain stage in the audio path.

Good luck.

 

[Gepetto]

Thanks Joe basically this sounds like the BillD mod... think I will order the parts and see if I can make this C-1 stand up and roar

Whatever that is...good luck Ray.

 

[roccus]

This is a modification swapping out old weak components in the C-1 to more efficient components making the C-1 perform way better than original.. if you scroll down a few posts take a look at a doc I attached C-1mod.doc it tells all about it mostly changing cap types and opamps like you had recommended

Whatever that is...good luck Ray.

 

[roccus]

Ordered the parts for the mod today... don't have a stock PL so why have a stock preamp?

 

[roccus]

C-1 stuff

Joe opinion please.. to do the OPA2134 op amps you need 2 of each at $4 each then the browndog adapter is $5 so that works out to $19 a pop..... would these work as well??? http://www.ebay.com/itm/121129742000 sure would be a lot easier on the pocket book.. I found a 3rd one that will need to be replaced the right channel on the MC phono input/output is dead

 

[Gepetto]

Joe opinion please.. to do the OPA2134 op amps you need 2 of each at $4 each then the browndog adapter is $5 so that works out to $19 a pop..... would these work as well??? http://www.ebay.com/itm/121129742000 sure would be a lot easier on the pocket book.. I found a 3rd one that will need to be replaced the right channel on the MC phono input/output is dead

That is exactly what is in there now Ray so why would you replace them with the same device?

The RC4136 was designed back in the early 80s as the first quad 741 op amp. For its time, the 741 was a phenomenal general purpose op amp. It is among the worst audio op amp choices however. We used them back then for DC motor controllers, the motors did not care about audio fidelity.