JoLida 502a former int amp

bikerboy

Hi,
Well it didnt take long before I had to hear what this amp can sound like without the cheap volume, balance and input pots. It sounds great and now I get to use the wireless remote control of the TAD again. It took about an hour to label and unsolder the controls and wire. I used a set of the stock jacks as the input. The input to the amp is clearly labeled on the board. I used cardas wire the first time and the cymbles sounded too splashy so I used silver plated copper wire and that sounds good. This amp has put the **** back in bass. The bass is full, not boomy and goes plenty low. The top is a little more mellow than the B&K amp I used before. At first I missed the extended range but now that I have listened to it for a good part of yesterday, I find it is easier to hear the midrange and the bass is a bigger part of the scene. The imaging is great and as good as the B&K. I rolled tubes in the TAD and the JoLida and have found a good setup. RCA triple mica 5814 black plates in the preamp and EH 12at7 in the amp. I will get some RCA 12ax7 to try in the amp from Doro later. That could be a hot setup. We'll see. Next mods will be hexfred diodes and better caps. I am so glad I finally got into tubes. First the TAD and now the JoLida. Music sounds smoother, more relaxed, not in your face. I wish I could have afforded Russman's Dodd amp but that came up after I got this and it was 2x the price. The only negative about this amp I can hear or see is the transformer is loud enough to hear when no sound is coming from the speakers. Maybe rubber washers between it and the chassis will help. More later in the diy forum I'm sure. Peace and hair grease.

AndyGwis

Nice review. You seem to really know your way around the inside of that thing.

So, would you say it is a night and day difference from the sound you had before with your B&K amp (not sure what pre you had)?

In all honesty, I think the sound from my old B&K ST-202 and B&K Pro-10MC was on par with my new MF A3.2 integrated . . . but the MF is much better looking, smaller, remote controllable, and 20 years newer.

B&K sound has always impressed me. Just bought a B&K amp off CL (ST-1430II) to run my HT L, R, C.

Congrats on getting a great integrated! I love the convenience of an integrated over my old B&K gear, that's for sure.

madmax

I have the balance control on mine bypassed. I think it makes a good difference but my comparison was another identical amp so I can't be sure that is all of it.
madmax

Early B.

Very cool.

Once you replace the caps (with Sonicaps, of course!) and diodes, you'll get another layer of detail and clarity.

Question: has the preamp section bypassed altogether when switching this int. amp to a pure amp? Just wondering the extent to which the preamp tubes still play a role here.

Thanks.

dorokusai

That's an easily modded amp and there is all kinds of information on the internet for tweaks here and there. Nice work!

bikerboy

Hi,
Early: I guess it isnt really a true amp but I dont know what it would be called. I was worried that the driver section would need to be bypassed but the gain needed isnt much different than when I used the B&K. As far as sound I dont know what difference it would make to bypass them. For caps I may use Auricaps or Sonicaps, havent decided yet.
Madmax:You had questions about the sub out. If you want the whole wire-switch-volume pot assembly you can have it. It would be easy to set yours up with the parts in front of you or just use this one and do a r&r.
Andy: I liked the B&K amp but found with my room, speakers ect there was too much top end and not enough bass. Imaging was very good and the bass was there but the top end sounded too bright , dry or in your face. Now there is a better balance. I dont like boomy mid bass and have found speaker placement that is very different than what is recommended by polk. I found Cardas recommended Golden ratio works very well. His website has lots of great info and that is one idea I used to find the best speaker placement. Imaging and bass are more precise and clear. I had a B&K ST-202, actually still do. I guess I need to post it but a coworker is interest. Thanks for the ideas and questions.:D

AndyGwis

Yeah, I had the B&K ST-202 as well, then sold it to Sucks2beme to help fund my MF A3.2. I think he then sold it after a few months to fund his Audo Research amp. Loved it for the year+ I owned it in both my HT rig originally, then as the anchor of my 2-channel rig once I started to build that.

I guess B&K is simply a great pit-stop on the road trip towards audio nirvana.

sucks2beme

AndyGwis wrote: »

Yeah, I had the B&K ST-202 as well, then sold it to Sucks2beme to help fund my MF A3.2. I think he then sold it after a few months to fund his Audo Research amp. Loved it for the year+ I owned it in both my HT rig originally, then as the anchor of my 2-channel rig once I started to build that.

I guess B&K is simply a great pit-stop on the road trip towards audio nirvana.

The B&K and Rotel are still hiding in my closet!